Moderator- DR. M.C. BANSAL Professor DEPTT. OF OBS & GYN NIMS MEDICAL COLLEGE & HOSPITAL IMAGING IN OBSTETRICS & GYNAECOLOGY DR. RIDHI KATHURIA PG 2 ND year DEPTT OF OBS & GYN NIMS MEDICAL COLLEGE & HOSPITAL JAIPUR
Imaging in obstetrics & gynaecology part 2
Nov 30, 2014
USG in Obs & Gyn
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Transcript
Moderator-
DR MC BANSALProfessor
DEPTT OF OBS amp GYNNIMS MEDICAL COLLEGE amp HOSPITAL
IMAGING IN OBSTETRICS amp GYNAECOLOGY
DR RIDHI KATHURIAPG 2ND year
DEPTT OF OBS amp GYNNIMS MEDICAL COLLEGE amp HOSPITAL
JAIPUR
ULTRASOUND IN
OBSTETRICS
Obstetric ultrasound examination at any stage in pregnancy serves two important functions Diagnostic and Screening
While many major fetal defects can be diagnosed in the first trimester the diagnostic accuracy of an ultrasound scan is significantly greater in the mid-second trimester due to the larger size and more advanced development of the fetus
HCG Levels for normal Pregnancy
NOTE The quantitative maternal serum beta HCG peaks at approximately 10 weeks and then reduces
Initial confirmation of
pregnancy is done by a Urine for
Pregnancy Test kit
The kit detects hCG beta subunit in urine in
concentration as low as 25
mIUml
1st TRIMESTER SCAN
The First Trimester is defined as the first 12 weeks of pregnancy following the last
normal menstrual period (some authors refer to early pregnancy as 0 -
10 weeks)
It can be divided into a number of phases each of which has typical clinical issues These
phases areConceptus phase 3 - 5 weeksEmbryonic phase 6 - 9 weeks
Fetal phase 10 - 12 weeks
Ultrasound during this period is predominantly concerned with the following clinical issues
1 Dating of the pregnancyMSD mean sac diameterCRL crown rump length (most accurate)
2 Early pregnancy failureThreatened abortionMissed abortionInevitable abortionIncomplete abortionComplete abortionAn-embryonic pregnancy Blighted Ovum
3 Confirming intrauterine pregnancy (IUP)Double Decidual Sac SignIntradecidual SignDouble Bleb Sign
4 Ectopic pregnancy
5 Nuchal lucency
GESTATIONAL SACbull GS is the earliest sonographic finding
in pregnancy
bull It will be difficult to see if the mother has a retroverted uterus or fibroids
bull The GS is an echogenic ring (formed by chorio-emryonic cells) surrounding an anechoic centre (as fluid filled)
bull An ectopic pregnancy will appear the same but it will not be within the endometrial cavity
bull The GS is not identifiable until approximately 4 12 weeks with a transvaginal scan
bull Gestational sac size should be determined by measuring the mean of three diameters These differences rarely effect gestational age dating by more than a day or two
5 week gestation Yolk Sac Only seen
The yolk sac will be visible before a clearly definable embryonic pole
Mean Sac Diameter measurement is used to determine gestational age before a Crown Rump length can be clearly measured
The average sac diameter is determined by measuring the length width and height then dividing by 3
YOLK SAC
A Yolk Sac is first anatomical structure identified within the gestational sac
It plays a critical role in embryonal development by providing nutrients serving as the site of initial haematopoiesis and contributing to the development of gastrointestinal and reproductive systems
The yolk sac appears during the 5th week
It is the second structure to appear after the GS
It should be round with an anechoic centre
It should not be calcified misshapen or gt5mm from the inner to inner diameter
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
ULTRASOUND IN
OBSTETRICS
Obstetric ultrasound examination at any stage in pregnancy serves two important functions Diagnostic and Screening
While many major fetal defects can be diagnosed in the first trimester the diagnostic accuracy of an ultrasound scan is significantly greater in the mid-second trimester due to the larger size and more advanced development of the fetus
HCG Levels for normal Pregnancy
NOTE The quantitative maternal serum beta HCG peaks at approximately 10 weeks and then reduces
Initial confirmation of
pregnancy is done by a Urine for
Pregnancy Test kit
The kit detects hCG beta subunit in urine in
concentration as low as 25
mIUml
1st TRIMESTER SCAN
The First Trimester is defined as the first 12 weeks of pregnancy following the last
normal menstrual period (some authors refer to early pregnancy as 0 -
10 weeks)
It can be divided into a number of phases each of which has typical clinical issues These
phases areConceptus phase 3 - 5 weeksEmbryonic phase 6 - 9 weeks
Fetal phase 10 - 12 weeks
Ultrasound during this period is predominantly concerned with the following clinical issues
1 Dating of the pregnancyMSD mean sac diameterCRL crown rump length (most accurate)
2 Early pregnancy failureThreatened abortionMissed abortionInevitable abortionIncomplete abortionComplete abortionAn-embryonic pregnancy Blighted Ovum
3 Confirming intrauterine pregnancy (IUP)Double Decidual Sac SignIntradecidual SignDouble Bleb Sign
4 Ectopic pregnancy
5 Nuchal lucency
GESTATIONAL SACbull GS is the earliest sonographic finding
in pregnancy
bull It will be difficult to see if the mother has a retroverted uterus or fibroids
bull The GS is an echogenic ring (formed by chorio-emryonic cells) surrounding an anechoic centre (as fluid filled)
bull An ectopic pregnancy will appear the same but it will not be within the endometrial cavity
bull The GS is not identifiable until approximately 4 12 weeks with a transvaginal scan
bull Gestational sac size should be determined by measuring the mean of three diameters These differences rarely effect gestational age dating by more than a day or two
5 week gestation Yolk Sac Only seen
The yolk sac will be visible before a clearly definable embryonic pole
Mean Sac Diameter measurement is used to determine gestational age before a Crown Rump length can be clearly measured
The average sac diameter is determined by measuring the length width and height then dividing by 3
YOLK SAC
A Yolk Sac is first anatomical structure identified within the gestational sac
It plays a critical role in embryonal development by providing nutrients serving as the site of initial haematopoiesis and contributing to the development of gastrointestinal and reproductive systems
The yolk sac appears during the 5th week
It is the second structure to appear after the GS
It should be round with an anechoic centre
It should not be calcified misshapen or gt5mm from the inner to inner diameter
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Obstetric ultrasound examination at any stage in pregnancy serves two important functions Diagnostic and Screening
While many major fetal defects can be diagnosed in the first trimester the diagnostic accuracy of an ultrasound scan is significantly greater in the mid-second trimester due to the larger size and more advanced development of the fetus
HCG Levels for normal Pregnancy
NOTE The quantitative maternal serum beta HCG peaks at approximately 10 weeks and then reduces
Initial confirmation of
pregnancy is done by a Urine for
Pregnancy Test kit
The kit detects hCG beta subunit in urine in
concentration as low as 25
mIUml
1st TRIMESTER SCAN
The First Trimester is defined as the first 12 weeks of pregnancy following the last
normal menstrual period (some authors refer to early pregnancy as 0 -
10 weeks)
It can be divided into a number of phases each of which has typical clinical issues These
phases areConceptus phase 3 - 5 weeksEmbryonic phase 6 - 9 weeks
Fetal phase 10 - 12 weeks
Ultrasound during this period is predominantly concerned with the following clinical issues
1 Dating of the pregnancyMSD mean sac diameterCRL crown rump length (most accurate)
2 Early pregnancy failureThreatened abortionMissed abortionInevitable abortionIncomplete abortionComplete abortionAn-embryonic pregnancy Blighted Ovum
3 Confirming intrauterine pregnancy (IUP)Double Decidual Sac SignIntradecidual SignDouble Bleb Sign
4 Ectopic pregnancy
5 Nuchal lucency
GESTATIONAL SACbull GS is the earliest sonographic finding
in pregnancy
bull It will be difficult to see if the mother has a retroverted uterus or fibroids
bull The GS is an echogenic ring (formed by chorio-emryonic cells) surrounding an anechoic centre (as fluid filled)
bull An ectopic pregnancy will appear the same but it will not be within the endometrial cavity
bull The GS is not identifiable until approximately 4 12 weeks with a transvaginal scan
bull Gestational sac size should be determined by measuring the mean of three diameters These differences rarely effect gestational age dating by more than a day or two
5 week gestation Yolk Sac Only seen
The yolk sac will be visible before a clearly definable embryonic pole
Mean Sac Diameter measurement is used to determine gestational age before a Crown Rump length can be clearly measured
The average sac diameter is determined by measuring the length width and height then dividing by 3
YOLK SAC
A Yolk Sac is first anatomical structure identified within the gestational sac
It plays a critical role in embryonal development by providing nutrients serving as the site of initial haematopoiesis and contributing to the development of gastrointestinal and reproductive systems
The yolk sac appears during the 5th week
It is the second structure to appear after the GS
It should be round with an anechoic centre
It should not be calcified misshapen or gt5mm from the inner to inner diameter
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
HCG Levels for normal Pregnancy
NOTE The quantitative maternal serum beta HCG peaks at approximately 10 weeks and then reduces
Initial confirmation of
pregnancy is done by a Urine for
Pregnancy Test kit
The kit detects hCG beta subunit in urine in
concentration as low as 25
mIUml
1st TRIMESTER SCAN
The First Trimester is defined as the first 12 weeks of pregnancy following the last
normal menstrual period (some authors refer to early pregnancy as 0 -
10 weeks)
It can be divided into a number of phases each of which has typical clinical issues These
phases areConceptus phase 3 - 5 weeksEmbryonic phase 6 - 9 weeks
Fetal phase 10 - 12 weeks
Ultrasound during this period is predominantly concerned with the following clinical issues
1 Dating of the pregnancyMSD mean sac diameterCRL crown rump length (most accurate)
2 Early pregnancy failureThreatened abortionMissed abortionInevitable abortionIncomplete abortionComplete abortionAn-embryonic pregnancy Blighted Ovum
3 Confirming intrauterine pregnancy (IUP)Double Decidual Sac SignIntradecidual SignDouble Bleb Sign
4 Ectopic pregnancy
5 Nuchal lucency
GESTATIONAL SACbull GS is the earliest sonographic finding
in pregnancy
bull It will be difficult to see if the mother has a retroverted uterus or fibroids
bull The GS is an echogenic ring (formed by chorio-emryonic cells) surrounding an anechoic centre (as fluid filled)
bull An ectopic pregnancy will appear the same but it will not be within the endometrial cavity
bull The GS is not identifiable until approximately 4 12 weeks with a transvaginal scan
bull Gestational sac size should be determined by measuring the mean of three diameters These differences rarely effect gestational age dating by more than a day or two
5 week gestation Yolk Sac Only seen
The yolk sac will be visible before a clearly definable embryonic pole
Mean Sac Diameter measurement is used to determine gestational age before a Crown Rump length can be clearly measured
The average sac diameter is determined by measuring the length width and height then dividing by 3
YOLK SAC
A Yolk Sac is first anatomical structure identified within the gestational sac
It plays a critical role in embryonal development by providing nutrients serving as the site of initial haematopoiesis and contributing to the development of gastrointestinal and reproductive systems
The yolk sac appears during the 5th week
It is the second structure to appear after the GS
It should be round with an anechoic centre
It should not be calcified misshapen or gt5mm from the inner to inner diameter
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
1st TRIMESTER SCAN
The First Trimester is defined as the first 12 weeks of pregnancy following the last
normal menstrual period (some authors refer to early pregnancy as 0 -
10 weeks)
It can be divided into a number of phases each of which has typical clinical issues These
phases areConceptus phase 3 - 5 weeksEmbryonic phase 6 - 9 weeks
Fetal phase 10 - 12 weeks
Ultrasound during this period is predominantly concerned with the following clinical issues
1 Dating of the pregnancyMSD mean sac diameterCRL crown rump length (most accurate)
2 Early pregnancy failureThreatened abortionMissed abortionInevitable abortionIncomplete abortionComplete abortionAn-embryonic pregnancy Blighted Ovum
3 Confirming intrauterine pregnancy (IUP)Double Decidual Sac SignIntradecidual SignDouble Bleb Sign
4 Ectopic pregnancy
5 Nuchal lucency
GESTATIONAL SACbull GS is the earliest sonographic finding
in pregnancy
bull It will be difficult to see if the mother has a retroverted uterus or fibroids
bull The GS is an echogenic ring (formed by chorio-emryonic cells) surrounding an anechoic centre (as fluid filled)
bull An ectopic pregnancy will appear the same but it will not be within the endometrial cavity
bull The GS is not identifiable until approximately 4 12 weeks with a transvaginal scan
bull Gestational sac size should be determined by measuring the mean of three diameters These differences rarely effect gestational age dating by more than a day or two
5 week gestation Yolk Sac Only seen
The yolk sac will be visible before a clearly definable embryonic pole
Mean Sac Diameter measurement is used to determine gestational age before a Crown Rump length can be clearly measured
The average sac diameter is determined by measuring the length width and height then dividing by 3
YOLK SAC
A Yolk Sac is first anatomical structure identified within the gestational sac
It plays a critical role in embryonal development by providing nutrients serving as the site of initial haematopoiesis and contributing to the development of gastrointestinal and reproductive systems
The yolk sac appears during the 5th week
It is the second structure to appear after the GS
It should be round with an anechoic centre
It should not be calcified misshapen or gt5mm from the inner to inner diameter
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Ultrasound during this period is predominantly concerned with the following clinical issues
1 Dating of the pregnancyMSD mean sac diameterCRL crown rump length (most accurate)
2 Early pregnancy failureThreatened abortionMissed abortionInevitable abortionIncomplete abortionComplete abortionAn-embryonic pregnancy Blighted Ovum
3 Confirming intrauterine pregnancy (IUP)Double Decidual Sac SignIntradecidual SignDouble Bleb Sign
4 Ectopic pregnancy
5 Nuchal lucency
GESTATIONAL SACbull GS is the earliest sonographic finding
in pregnancy
bull It will be difficult to see if the mother has a retroverted uterus or fibroids
bull The GS is an echogenic ring (formed by chorio-emryonic cells) surrounding an anechoic centre (as fluid filled)
bull An ectopic pregnancy will appear the same but it will not be within the endometrial cavity
bull The GS is not identifiable until approximately 4 12 weeks with a transvaginal scan
bull Gestational sac size should be determined by measuring the mean of three diameters These differences rarely effect gestational age dating by more than a day or two
5 week gestation Yolk Sac Only seen
The yolk sac will be visible before a clearly definable embryonic pole
Mean Sac Diameter measurement is used to determine gestational age before a Crown Rump length can be clearly measured
The average sac diameter is determined by measuring the length width and height then dividing by 3
YOLK SAC
A Yolk Sac is first anatomical structure identified within the gestational sac
It plays a critical role in embryonal development by providing nutrients serving as the site of initial haematopoiesis and contributing to the development of gastrointestinal and reproductive systems
The yolk sac appears during the 5th week
It is the second structure to appear after the GS
It should be round with an anechoic centre
It should not be calcified misshapen or gt5mm from the inner to inner diameter
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
GESTATIONAL SACbull GS is the earliest sonographic finding
in pregnancy
bull It will be difficult to see if the mother has a retroverted uterus or fibroids
bull The GS is an echogenic ring (formed by chorio-emryonic cells) surrounding an anechoic centre (as fluid filled)
bull An ectopic pregnancy will appear the same but it will not be within the endometrial cavity
bull The GS is not identifiable until approximately 4 12 weeks with a transvaginal scan
bull Gestational sac size should be determined by measuring the mean of three diameters These differences rarely effect gestational age dating by more than a day or two
5 week gestation Yolk Sac Only seen
The yolk sac will be visible before a clearly definable embryonic pole
Mean Sac Diameter measurement is used to determine gestational age before a Crown Rump length can be clearly measured
The average sac diameter is determined by measuring the length width and height then dividing by 3
YOLK SAC
A Yolk Sac is first anatomical structure identified within the gestational sac
It plays a critical role in embryonal development by providing nutrients serving as the site of initial haematopoiesis and contributing to the development of gastrointestinal and reproductive systems
The yolk sac appears during the 5th week
It is the second structure to appear after the GS
It should be round with an anechoic centre
It should not be calcified misshapen or gt5mm from the inner to inner diameter
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Mean Sac Diameter measurement is used to determine gestational age before a Crown Rump length can be clearly measured
The average sac diameter is determined by measuring the length width and height then dividing by 3
YOLK SAC
A Yolk Sac is first anatomical structure identified within the gestational sac
It plays a critical role in embryonal development by providing nutrients serving as the site of initial haematopoiesis and contributing to the development of gastrointestinal and reproductive systems
The yolk sac appears during the 5th week
It is the second structure to appear after the GS
It should be round with an anechoic centre
It should not be calcified misshapen or gt5mm from the inner to inner diameter
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
YOLK SAC
A Yolk Sac is first anatomical structure identified within the gestational sac
It plays a critical role in embryonal development by providing nutrients serving as the site of initial haematopoiesis and contributing to the development of gastrointestinal and reproductive systems
The yolk sac appears during the 5th week
It is the second structure to appear after the GS
It should be round with an anechoic centre
It should not be calcified misshapen or gt5mm from the inner to inner diameter
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
A Yolk Sac is first anatomical structure identified within the gestational sac
It plays a critical role in embryonal development by providing nutrients serving as the site of initial haematopoiesis and contributing to the development of gastrointestinal and reproductive systems
The yolk sac appears during the 5th week
It is the second structure to appear after the GS
It should be round with an anechoic centre
It should not be calcified misshapen or gt5mm from the inner to inner diameter
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
The yolk sac appears during the 5th week
It is the second structure to appear after the GS
It should be round with an anechoic centre
It should not be calcified misshapen or gt5mm from the inner to inner diameter
Yolk sacs larger than 6 mm are usually indicative of an abnormal pregnancy
Failure to identify (with transvaginal ultrasound) a yolk sac when the gestational sac has grown to 12 mm is also usually indicative of a failed pregnancy
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Visualization of a yolk sac is useful in distinguishing an intrauterine pregnancy (IUP) from a pseudo gestational sac a decidual cast cyst or a blighted ovum as it is only seen in
theIUP
A yolk sac should always be seen when the mean sac diameter (MSD) is 20 mm on trans-abdominal scanning and usually seen
trans-vaginally with an MSD of 8 - 10 mm
In general if the MSD is 16 mm or greater and no fetal pole yolk sac can be identified on trans-vaginal scanning then this
suggests a non-viable pregnancy (an-embryonic pregnancy)
Repeat scanning with an larger MSD and serial quantitative beta-HCGs is however thought prudent
In a normal early pregnancy the diameter of the yolk sac should usually be lt 6 mm while its shape should be near spherical
Visualisation multiple yolk sacs is the earliest sign of a polyamniotic pregnancy eg twins
Natural courseAs the pregnancy advances the yolk sac
disappears and is often sonographically not detectable after 14 weeks
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
DOUBLE DECIDUAL
SIGN Double Decidual Sac Sign (DDSS) is a useful feature on early pregnancy ultrasound in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac
It consists of the Decidua Parietalis (that lining the uterine cavity) and Decidua Capsularis (lining the gestational sac) and is seen as two concentirc rings surrounding an anechoic gestational sac
Where the two adhere is the Decidua Basalis and is the site of future placental formation
With good quality high frequency transvaginal scanning a yolk sac should also be present at this time
Should a definite IUP not be confirmed on sonography then repeat scanning and serial quantitative beta-HCGs are required until either an IUP is established an ectopic pregnancy is visualised or beta-HCGs return to zero (implying miscarriage)
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
DOUBLE BLEB SIGN
bull A Double Bleb Sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles
bull The embryonic disc is located between the two bubbles
bull It is an important feature of an intrauterine pregnancy and thus distinguishes a pregnancy form a pseudogestational sac or decidual cast cyst
bull It should not be confused with the double decidual sac sign
Yolk sac
Embryonc Disc
Amniotic sac
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
The CRL is a reproducible and accurate method for measuring and dating a fetus
Early ultrasonographers used this term (CRL) because early fetuses also adopted the sitting in the chair posture in early pregnancy
After 12 weeks the accuracy of CRL in predicting gestational age diminishes and is replaced by measurement of the fetal biparietal
diameter
In at least some respects the term crown rump length is misleading there is no fetal crown and no fetal rump to measure in 1st trimester
CROWN RUMP LENGTH
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Until 53 days (9weeks) from the LMP the most caudal portion of the fetal cell mass is the Caudal Neurospone followed by the
tail
Only after 53 days (9weeks) is the fetal rump the most caudal portion of the fetus
Until 60 days (105 weeks) from the LMP the most cephalad portion of the fetal cell mass is initially the Rostral
Neurospore and later the cervical flexure
After 60 days (105 weeks) the fetal head becomes the most cephalad portion of the fetal cell mass
What is really measured during this early development of the fetus is the longest fetal diameter
From 6 weeks to 9 12 weeks gestational age the fetal CRL grows at a rate of about 1 mm per
day
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
bull Crown Rump Length (CRL) measurement in a 6 week
gestation
bull A mass of fetal cells separate from the yolk sac first becomes
apparent on transvaginal ultrasound just after the 6th week
of gestation
bull This mass of cells is known as the Fetal Pole
bull The fetal pole grows at a rate of about 1 mm a day starting at the
6th week of gestational age
bull Thus a simple way to date an early pregnancy is to add the
length of the fetus (in mm) to 6 weeks
bull Using this method a fetal pole measuring 5 mm would have a
gestational age of 6 weeks and 5 days
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Outside to Outside Measurements
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
FETAL HEART PULSATIONS
Using a transvaginal approach the fetal heart beat can be seen flickering before the fetal pole is even identified
It will be seen alongside the yolk sac
It may be below 100 beats per minute but this will increase to between 120- 180 beats per minute by 7 weeks
In the early scans at 5-6 weeks just visualising a heart beating is the important thing
Failure to identify fetal cardiac activity in a fetus whose overall length is greater than 4 mm (approx 45 weeks)is an ominous
sign
Sometimes there is difficulty in distinguishing between the maternal pulse and fetal heart beat Often technicians will take the mothers pulse at the same time to check if it is the fetus or
the mothers
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
The very early embryonic heart will be a subtle flicker
This may be measured using M-Mode(avoid Doppler in the first
trimester due to risks of bioeffects)
Initially the heart rate may be slow
Compare to the maternal heart rate to confirm that one is not
seeing an arteriole
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
8 weeks
A normal 8 week foetal pole
One should see a definable head and
body The beginning of the
limb buds
The fetal heart should be easily visible
Subtle body movements can often be seen
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
NOTE- Demarcation between the Chorion amp Amnion
The 2 sacs are clearly visible
The outer chorion with the developing placenta and the inner amnion which will inflate with the production of fetal urine to adhere to the chorion obliterating the residual yolk sac
The normal small mid-gut hernia into the cord is still visible (pink shading)
This is the result of normal midgut proliferation and will resolve by 11 weeks as the fetus lengthens This physiological occurrence should not be confused with an omphalocele
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
NUCHAL TRANSLUCENCY
The Nuchal Translucency is a measurement performed during a specific period in the first trimester (113-136 weeks)
It should not be confused with Nuchal Thickness which is measured in the second trimester
An increased nuchal translucency is thought to relate to dilated lymphatic channels
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
ASSOCIATIONSIt can being associated with a number of anomlaies including ANEUPLOIDY
Trisomies ndash 13 18 21Turner syndrome
NON-ANEUPLOIDIC STRUCTURAL DEFECTS amp SYNDROMES
Congenital Diaphragmatic HerniationCongenital Heart DiseaseOmphalocoeleSkeletal DysplasiasSmith-Lemli-Opitz SyndromeVACTERL association
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
VACTERL association (also VATER syndrome) is a non-random association of birth defects
The reason it is called an association rather than a syndrome is that while the complications are not
pathogenetically related they tend to occur together more frequently than expected by chance
No specific genetic or chromosome problem has been identified
Can be seen with some chromosomal defects such as Trisomy 18 and is more frequently seen in babies of diabetic mothers
Most likely caused by multiple factors
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
ANAL DEFECTS
1 Atresia2 Imperforate
Anus
VERTEBRAL DEFECTS
1Hypoplastic Vertebrae
2Hemi-vertebrae3Scoliosis
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
TRACHEO-ESOPHAGEAL
DEFECTS
1 TO Fistula2 Esophageal Atresia
CARDIAC DEFECTS
1 VSD2 ASD3 TOF
4 TpGV5 Truncus
Arteriosus
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
LIMB DEFECTS
1 Hypoplastic Dysplastic thumb2 Polydactyly3 Syndactyly
4 Radial Aplasia
RENAL DEFECTS
1 Single Umbilical Artery
2 Incomplete formation of kidney(s)
3 Outflow obstruction
4 Severe reflux
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
RADIO GRAPHIC ASSESSMENT
Nuchal lucency is measured on a sagittal section through the fetus
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Use of the correct technique is essential
The fetus should be transverse (sagittal) in the imaging plane
The vertebral column should be facing the bottom of the screen
Fetal head should not be extended or flexed
Fetus should be floating free of the uterine wall (ie amniotic fluid should be seen between its back and the uterus)
Only the lucency is measured (again differing from nuchal thickness)
Ideally only the head and upper thorax should be included in the measurement
The level of magnification should be appropriate (fetus should
occupy most of the image) enabling 1mm changes in measurement possible
The + calipers should be used for measurement
The widest part of the measurement should be taken
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
1 Only values obtained when CRL values are between 45-84 mm are considered valid
2 The lucent region is generally not septated
3 The thickness rather than the appearance (morphology) is considered to be directly
related to the incidence of chromosomal and other anomalies
4 A normal value is usually less than roughly 25-30 mm in
thickness however it is maternal age
dependent and needs to be matched to exact
gestational age and crown rump length (CRL)
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
The nuchal translucency cannot be adequately assessed if there is -
Unfavourable fetal lie
Unfavourable gestational age - CRL lt 45 or gt 84 mm
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Most likely a case of Hydrops
Fetalis-
1Incresed NT
2Oedema under the skin
3Evidence of Ascites
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Interpretationbull Detection rates for
aneupliodic anomalies with nuchal translucency alone approaches 80 - 90 with a false positive rate of ~ 5
Correlation With Serum Markers
bull To increase the clinical accuracy of
nuchal lucency it can be correlated with serum markers such as
bull maternal B-HCGbull alpha feto protein (AFP)bull pregnancy associated
plasma protein A (PAPP-A)bull oestriol
Further work up
bull If abnormal gt further work up is carried out which includes
bull Amniocentesis and or Chorionic Villus sampling
bull Fetal echocardiography
Natural course - progressionbull As the second trimester approaches
the region of nuchal translucency might either
bull Regress ndash if chromosomally normal a large
proportion of fetuses will have a normal outcome
ndash spontaneous regression does not however mean a normal karyotype
bull Evolve into andash Nuchal Oedemandash Cystic Hygroma
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
ABORTIONS
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
MISSED ABORTIO
Nbull A CRL of ge 7mm without a heart
beat on a transvaginal ultrasound confirms the diagnosis
(by RCOG criteria)
bull Additional clues are presence of abnormal hyperechoic material within the uterine cavity and an irregular gestational sac
bull If there is an absence of heart beat in a fetus that is less than 7mm the diagnosis of miscarriage cannot be made with certainty
bull This scenario is termed Pregnancy Of Uncertain Viability (PUV) and followup with ultrasound (generally in 7-10 days) and serial bHCG recommended
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
bull Irregular Sac
bull Hyperechoic collection within the sac
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
INEVITABLE ABORTIONbull Refers to the presence of an
open cervix in the context of bleeding in the first trimester of pregnancy
bull Essentially a threatened abortion progresses to an inevitable abortion if cervical dilatation occurs Once tissue has passed through the cervical os this will then be termed an incomplete abortion and ultimately a complete abortion
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
THREATENED ABORTION
A subchorionic haemorrhage is often seen but
unless large does not carry a poor
prognosis
Features which do predict poor
outcome includebull Fetal bradycardia lt
80 - 90 bpmbull Small or
Irregular Gestational Sac MSD - CRL lt 5 mmbull Large Subchorionic
Haemorrhage
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
One important difference is to be deduced between an actual irregular sac amp a sac which
appears irregular due to Braxton-Hickrsquos contractions
The former one will not change its shape to become normal with time
However the later will change shape with time The patient is allowed to lay at
rest for few minutes amp put the probe again to confirm A changed contour of the sac regular appearing sac on 2nd
look helps the jeopardy
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Shows an empty
uterus with no fetal
components or products
of conception
COMPLETE ABORTION
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
INCOMPLETE
ABORTIONRetained
Products of Conception
still seen within the uterine cervical cavity
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
BLIGHTED OVUMAn anembryonic pregnancy may be diagnosed when there is no fetal pole identified on trans-vaginal scanning the size of the gestational sac is such that a fetal pole should be seenMSD ge 25 mm (by RCOG criteria)
There is little or no growth of the
gestational sac between interval
scans
Normally the MSD should
increase by 1 mm per day
If MSD is too small to ascertain viability
on the initial ultrasound a follow
up scan in 10-14 days should
differentiate early pregnancy from a failed pregnancy
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Other ancillary features include
Absent yolk sac when MSD gt 8 mm
Poor decidual reaction
often lt 2 mm
Irregular gestational sac shape
Abnormally low sac position
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
ECTOPIC GESTATION
UTERUSEmpty uterine cavity no evidence of intra-uterine pregnancyPseudogestational sac decidual cyst - may be seen in 10 ndash 20 of ectopic pregnanciesDecidual cast
TUBE AND OVARYSimple adnexal cyst 10 chance of an ectopic
Complex adnexal cyst mass 95 chance of an tubal ectopic
Tubal ring sign 95 chance of an tubal ectopic if seendescribed in 49 of ectopics and in 68 of unruptured ectopics
Ring of fire sign can be seen on colour Doppler in a tubal ectopic
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
PERITONEAL CAVITY
Free pelvic fluid Haemoperitoneum in the Pouch Of Douglas
The presence of free intra peritoneal fluid in the context of a positive beta HCG and empty uterus is
~ 70 specific for an ectopic pregnancy ~ 63 sensitive for an ectopic pregnancy
Live Pregnancy 100 specific but only seen in a minority of cases
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
LOCATIONSTUBAL ECTOPIC 93 - 97
Ampullary Ectopic most common ~ 70 of tubal ectopics and ~ 65 - 68 of all
ectopicsIsthmal Ectopic ~ 12 of tubal ectopics and ~ 11 of all ectopicsFimbrial Ectopic ~ 11 of tubal ectopics and ~ 10 of all ectopics
ATYPICAL ECTOPIC PREGNANCIES
Interstitial Ectopic - cornual ectopic 3 - 4 also essentially a type of
tubal ectopicOvarian Ectopic - ovarian pregnancy 05 - 1 Cervical Ectopic - cervical pregnancy rare lt 1 Scar Ectopic site of previous Caesarian section scar rareAbdominal Ectopic rare ( ~ 14)
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
OVARIAN ECTOPIC
PREGNANCY
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
TUBAL ECTOPIC PREGNANCY
Transvaginal scan showing fluid with
debris at the cul-de-sac
Empty endometrium with a normal size
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
The presence of Ring of Fire sign confirms the anechoic shadow to be a GS
Color and spectral doppler demonstrates a right anechoic tubal mass
with tracings similar to fetal heart rate RING OF FIRE SIGN
(HYPERVASCULAR RING)
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
2ND amp 3RD TRIMESTE
R SCANNIN
G
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
2nd trimester scan is a routinely performed ultrasound examination on all pregnancies
This scan emphasizes on fetal anatomy and therefore is also called a
2nd Trimester Anatomy Scan OR
Fetal Anomaly Scan OR
TIFFA (Targeted Imaging For Fetal Anomalies) Scan
Period extends from 13 weeks 0 days to 27 weeks 6
days
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
1Fetal Skull - Integrity Shape
2Fetal Brain - Ventricles Choroid Plexus Mid Brain Posterior Fossa
3Fetal Face - Profile Orbits (including Interocular Diameter And Binocular Diameter) Upper Lip
4Fetal Neck - Nuchal Thickness
5Fetal Spine - Transverse As Well As Longitudinal Views
6Fetal HeartFetal Heart Rate Rhythm
Four Chamber ViewOutflow Tract Views
Aortic Arch View
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
7 Fetal Thorax - Thoracic Shape Size Lungs Diaphragm
8 Fetal Abdomen - Stomach (including Situs) Liver Kidneys Bladder Abdominal Wall Umbilicus
9 Fetal Limbs - Echogenicity Measurements Hands Movements
In addition to this Standard Fetal Biometric Parameters
as well as the following features are also assessed
Fetal LiePlacental Position
Liquor VolumeCord Number Of Cord Vessels
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
FETAL SKULL
Round Skull shadow
Middle Fossa in focus here
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Cavum Septum Pellucidum
Thalamus
Lateral Lobe
Vermis
Cisterna Magna
Choroid Plexus
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
BI-PARIETAL DIAMETRE
Measured at a focus which shows both the THALAMI amp the CAVUM SEPTUM
PELLUCIDUM preferably with the Sylvian Fissure in the same image
Both the thalami when seen together as two anechoic structures
represent the ldquoTrishool Signrdquo
Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
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Accuracy ndash 7-10 days upto 24 weeks amp 2-3 weeks during the 3rd trimester
MeasurementThe outer table of the skull on the superior end of the image upto the inner table of the skull at the inferior end of the image
BPD
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
LIMITATIONSbull Not useful when the head shape is abnormal ie elongated
(Dolicocephaly) or excessively round (Brachecephaly)
bull Better to use the parameter of CEPHALIC INDEX (CI) instead of BPD alone
bull Also the CI remains constant during the 3rd trimester
bull BPD is commonly effected by fetal position Eg Breech presentation
Cephalic Index (CI) = Bipareital Diameter (BPD) Occipitofrontal Diameter (OFD) X 100
bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
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bull The cephalic index gives an idea of the fetal head shape
bull It can change according to various situations such as 1 Presentation eg Breech presentation2 Ruptured membrances3 Presence of a twin pregnancy
bull The usual range is variable depending on various sources and different demographic groups
bull Often the mean value is taken ~ 78 (range 74 - 83)
bull An grossly decreased cephalic index suggests Dolichocephaly while a grossly increased one can suggest Brachycephaly
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
OCCIPITO-FRONTAL DIAMETER
Measured between the most prominent part of the occipital bone amp the frontal
bone
The area in focus is the same which shows both the thalami as in BPD
Anterior Horn Of The Lateral Ventricle (Va) Posterior Horn Of The Lateral Ventricle (Vp)
Hemisphere (Hem)
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
TRANS CEREBELLAR DIAMETERRecently a lot of stress is being laid
on measuring of the TCD
It is believed to be effected at last and the least in cases of
IUGR
TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
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TCD
bullTranscerebellar Diameter (TCD)
bullCisterna Magna (CM)
bullNuchal Fold (NF)
Measured from the outer margin of one cererbellar hemisphere to the
outer margin of the other cerebellar hemisphere including
both the hemispheres amp the vermis
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
HEAD CIRCUMFERENCE
The area of scan is the same as that for BPD amp OFD measures ie the thalami amp cavum septum should be
seen
An ellipsoid should be used to mark out the fetal skull at its outer borders (as far as possible)
Unaffected by head shape
Towards the end of pregnancy it
is the best indicator of
Gestational Age
Not effected in IUGR until
vary late stages
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
ANENCEPHALYThe brain tissue except the a portion of the brainstem
is completely absentfails to develop
No skull vault cranium is seen
FROG EYES SIGN ndash two hollows that of the orbits are seen prominently
ACRANIA ndash the term is used when the cranium is absent amp major part of the brain tissue is present
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
HYDROCEPHALUSbull The choroid plexus within
the dilated ventricles are relatively small amp looses contact with the medial amp lateral wall
bull A very common appearance of choroids plexus is DANGLING CHOROID
bull A separation of upto 5 mm from ventricular wall may be considered normal
Lateral ventricle with greater than 10mm diameter is suspicious of
VENTRICULOMEGALY
10-12 mm is taken as borderline
Ventriculomegaly is diagnosed surely when the choroid plexuses lose contact
with one both walls
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
DANGLING CHOROID
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
CHOROID PLEXUS CYST
May be Unilateral or Bilateral
Usually transient amp benign
Seen in fetus normally between 16 ndash 21 weeks after which they start regressing
Normally not seen after 25 weeks
Association with chromosomal anomaly is less than 1
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
HOLOPROSENCEPHALY (HPE)
Rare congenital brain malformation resulting from incomplete separation of the two hemispheres
The three main sub types in order of decreasing
severity are
1 Alobar Holoprosencephaly
2 Semilobar Holoprosencephaly
3 Lobar Holoprosencephaly
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
ALOBAR HOLOPROSENCEPHALY
Single ventricle- Horseshoe shaped appearance
Hemispheres are fused to form a mass around the ventricle
Thalami are fused amp no Falx Cerebri is seen
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
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Did we mention you can add bookmarks include fades and trim your videos now
CYCLOPIA PROBOSCIS
Horseshoe Shaped Appearance
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
ALOBAR HOLOPROSENCEPHALY
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
LOBAR PROSENCEPHALY
a Nearly complete separation of the hemispheres with the falx
b Anteriorly the frontal horns of lateral ventricles are fused (so is the frontal brain parenchyma) Thus attaining a triangular shape
c Septum pellucidum is absent
d Thalami are separate
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
SEMI-LOBAR HOLOPROSENCEPHALY
The basic structure of the cerebral
lobes are present but are fused most
commonly anteriorly and at the thalami and there is partial
diverticulation of brain
o Absence Of Septum Pellucidum oMonoventricle With Partially Developed Occipital And Temporal Horns
o Rudimentary Falx Cerebri Absent Anteriorly
o Incompletely Formed Interhemispheric Fissure
o Partial Or Complete Fusion Of The Thalami
o Absent Olfactory Tracts And Bulbs
o Agenesis Or Hypoplasia Of The Corpus Callosum
o Incomplete Hippocampal Formation
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
SEMILOBAR HOLOPROSENCEPHALY
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
HYDRENCEPHALY
bull Due to BL occlusion of the Internal Carotid Arteries
bull Resulting infarction of the entire brain except the Posterior Fossa which is supplied by the Vertebral Arteries
bull It appears as a large empty cranial vault filled with fluid without any cortical brain parenchyma matter within
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
DANDY WALKER
CONTINUUM
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
DANDY-WALKER CONTINUUM consists of a group of anomalies where there is a posterior fossa cyst which
communicates with the fourth ventricle as well as abnormal development of the vermis
There are numerous forms and the classification is contentious
The forms which are typically included in the Dandy-Walker spectrum include
Dandy-Walker Malformation (Classic)
Dandy-Walker Variant
Other included conditionsFourth Ventriculocoele
Blakersquos Pouch CystMega Cisterna Magna
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Classically Dandy Walker malformation consists of the
triad of
1 Hypoplasia of the vermis
2 Cystic dilatation of the fourth ventricle extending posteriorly
3 Enlarged posterior fossa
Antenatal ultrasound may falsely over diagnose the condition if
scanned before 18 weeks due to the vermis not being properly
formed before that time
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
DANDY WALKER VARIANT
Partial vermian hypoplasia with
partial obstruction to the fourth ventricle
but without enlargement of the
posterior fossa
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
CLASSICAL DANDY WALKER MALFORMATION
DANDY WALKER VARIANT
MEGA CISTERNA MAGNA
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Relatively common congenital malformation of the spine
and posterior fossa characterised by
lumbosacral spina bifida aperta myelomeningocoele and a small posterior fossa with descent of the brain
stem
ARNOLD CHIARI TYPE-2
MALFORMATION
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Classical signs described on ultrasound include
LEMON HEAD SIGN
BANANA CEREBELLUM SIGN
There may also be evidence of fetal Ventriculomegaly due to obstructive effects as a result of downward cerebellar
herniation
Additionally many of the associated malformations (eg Corpus Callosal Dysgenesis) may be identified
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Classical LEMON HEAD SIGN
Breech in continuity of the skin over the spinal cord suggestive
of Spina Bifida
(seen here at the lumbosacral area as evident by the bladder seen in front of the
spine)
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
BANANA CEREBELLUM SIGN
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
bull Varying degrees of protrusion of the Vermis 4th Ventricle amp Medulla through the Foramen Magnum into the spinal cord
bull As a result Cisterna Magna can be obliterated or reduced
bull Cerebellar hemispheres come closer producing a BANANA SIGN
bull Hydrocephalus due to obstruction in lower ventricular area causing varying degrees of ventricular dilatation
bull Fetal bones angulate inwards producing the LEMON HEAD SIGN
(may be seen with Encephalocoele amp Thanatophoric Dysplasia)
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
LEMON HEAD SIGN
Several diagnostic points should be remembered about this sign
1 When obtaining images of the calvarium the transducer should not be angled downward anteriorly as the fetal orbits may simulate the lemon
sign
2 Seen more often in fetuses less than 24 weeks and may not be present in
older fetuses (usually disappears after 24 weeks 4 )
3 This may be due to the decreased pliability of the fetal calvarium with
advancing gestational age or the increased intracranial pressure with
associated hydrocephalus
4 This sign may be rarely seen in normal patients
( ~ 1 of cases) and in those with other non-neural axis abnormalities
It is seen on axial imaging
(usually antenatal ultrasound
although antenatal MRI will also
demonstrate this sign)
through the head and relates to
concavity (not just flattening)
of the frontal bones
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
ABNORMAL SKULL SHAPES
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
DOLICOCEPHALY BRACHYCEPHALY
CLOVER LEAF SKULL(Thanatotropic Dysplasia)
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
NUCHALTHICKNESSNUCHAL THICKNESS is a parameter that
is measured in a second
trimester scan (18 - 22 weeks)
and it is not to be
confused with Nuchal
Translucency (which is measured in
the first trimester)
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
The nuchal thickness is measured on an axial section through the head and the level of the thalami cavum
septi pellucidum amp cerebellar hemispheres (ie in the same plane that is used to assess posterior fossa
structures)
One caliper should be placed at the skin and the other against the outer edge of the bone of the occiput
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
An abnormal value is one that is more than 6 mm in
thickness
A thick nuchal fold is often considered the most sensitive and most specific (best) 2ndtrimester marker for Down syndrome with false positive rates as low as 1
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
The increase in nuchal fold thickness can be due to-
Scalp Edema - Downrsquos Syndrome IUFD Hydrops Fetalis
Lymph- Cystic Hygroma
Brain Matter - Early Encephalocoele
Fat ndash Macrosomia
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Associationsbull ANEUPLOIDY
ndash Trisomiesndash Turner syndrome
bull CONGENITAL HEART DISEASE
NATURAL COURSE
Most thickened nuchal folds tend to resolve towards the
third trimester but that does
not decrease the increased risk of aneuploidic
anomalies
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
The arrow shows a cystic growth arising from the neck (posteriorly)
16 week fetus with a septate cystic mass in the posterior and lateral aspect of the fetal neck
CYSTIC HYGROMA
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Color Doppler image shows that this mass is not the cord or part
of it
Fetal head shows evidence of mild scalp
edema (early fetal hydrops)
The fetal spine and calvarium show no bony defects thus
ruling out the possibility of fetal
meningocele or myelo-meningocele
encephalocele etc
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
FETAL FACE
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Measuring the Outer Orbital
Diametre
Measuring the Inter Orbital Diametre
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Profile used to see the Nose Upper Lip Lower
Lip Chin Philtrum Glabella
Profile used to see the Orbits the Inta-Orbital Distance (IOD)
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
3-D IMAGE OF THE FACE
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
MICROGNATHIA
SEVERE HYPER-TELORISM
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
CLEFT LIPCLEFT PALATE
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Sagittal scan amp post mortem fetus showing-
PROMINENT FOREHEAD
RETROGNATHIA
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
FETAL THORAX
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
Fountain Geyser
Want to jump to a bookmark in your video
Hover over the video and yoursquoll be pleasantly surprised
Did we mention you can add bookmarks include fades and trim your videos now
What about the beautiful transitions yoursquove been seeing
Exciting new transitions
They are new too
3 Deliver Your Presentation
Broadcast and compress for seamless delivery
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raquo Share your presentation in real-time with anyone with a browser directly from PowerPoint
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BROADCAST IT
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animations media and much more
Upload embed and share away
SPEAK FOR ITSELFLet Your Presentation
But waithellip Therersquos More
View your slides from anywhere
raquo Check out the PowerPoint Web App
raquo Access slides wherever you are
Access Anywhere
Whatrsquos Your MessagePOWERPOINT 2010
The abdominal circumference (AC) is a transverse section (coronal) through the fetal abdomen at the level where the umbilical vein enters the liver The AC may be measured directly or calculated from the AP and transverse abdominal measurements Both techniques give good results Although the AC can be used to calculate gestational age it is more useful in determining fetal weight Combined with the BPD with or without the fetal femur length reliable formulas can be used to predict fetal weight
Level I and Level II Scanning (Screening vs Targeted Scanning)Level I (screening) scanning consists of the basic evaluation listed above It is usually relatively simple to perform readily available and relatively inexpensive More detailed scanning (Level II or targeted scan) requires higher resolution (more expensive) equipment and sonographic skills that are more limited in their availablity and significantly more expensive Indications for a Level II scan may includeSuspicious findings on a Level I scanHistory of prior congenital anomalyInsulin dependent diabetes or other medical problem that increases the risk of anomalyHistory of seizure disorder particularly if being treated with medications known to increase the risk of anomalyTeratogen exposureElevated MSAFPSuspected chromosome abnormalitySymmetric IUGRFetal arrhythmiaOligohydramnios hydramniosAdvanced maternal age
- IMAGING IN OBSTETRICS amp GYNAECOLOGY
- ULTRASOUND IN OBSTETRICS
- Slide 3
- HCG Levels for normal Pregnancy NOTE The quantitative matern
- 1st TRIMESTER SCAN
- Slide 6
- GESTATIONAL SAC
- Slide 8
- YOLK SAC
- Slide 10
- Slide 11
- Slide 12
- DOUBLE DECIDUAL SIGN
- Slide 14
- DOUBLE BLEB SIGN
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- 8 weeks
- NOTE- Demarcation between the Chorion amp Amnion
- NUCHAL TRANSLUCENCY
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- abortions
- MISSED ABORTION
- Slide 41
- INEVITABLE ABORTION
- THREATENED ABORTION
- Slide 44
- Slide 45
- COMPLETE ABORTION
- INCOMPLETE ABORTION
- BLIGHTED OVUM
- Slide 49
- Slide 50
- Slide 51
- Slide 52
- LOCATIONS
- Slide 54
- TUBAL ECTOPIC PREGNANCY
- The presence of Ring of Fire sign confirms the anechoic shado
- 2ND amp 3rd TRIMESTER SCANNING
- Slide 58
- Slide 59
- Slide 60
- FETAL SKULL
- Slide 62
- BI-PARIETAL DIAMETRE
- Slide 64
- LIMITATIONS
- Slide 66
- Slide 67
- TRANS CEREBELLAR DIAMETER
- TCD
- HEAD CIRCUMFERENCE
- ANENCEPHALY
- Slide 72
- HYDROCEPHALUS
- Slide 74
- Slide 75
- Holoprosencephaly (HPE)
- Slide 77
- Slide 78
- ALOBAR HOLOPROSENCEPHALY
- LOBAR PROSENCEPHALY
- SEMI-LOBAR HOLOPROSENCEPHALY
- SEMILOBAR HOLOPROSENCEPHALY
- HYDRENCEPHALY
- DANDY WALKER CONTINUUM
- Slide 85
- Slide 86
- Slide 87
- Slide 88
- ARNOLD CHIARI TYPE-2 MALFORMATION
- Slide 90
- Slide 91
- BANANA CEREBELLUM SIGN
- Slide 93
- Slide 94
- LEMON HEAD SIGN
- ABNORMAL SKULL SHAPES
- Slide 97
- NUCHAL THICKNESS
- Slide 99
- Slide 100
- Slide 101
- Slide 102
- Slide 103
- Slide 104
- FETAL FACE
- Slide 106
- Slide 107
- Slide 108
- 3-D IMAGE OF THE FACE
- Slide 110
- Slide 111
- Slide 112
- FETAL THORAX
- Slide 114
- Slide 115
- Slide 116
- Fountain Geyser
- What about the beautiful transitions yoursquove been seeing
- Deliver Your Presentation
- Slide 120
- SPEAK FOR ITSELF
- But waithellip Therersquos More
- Access Anywhere
- Slide 124
- Slide 125
- Slide 126
-
3 Deliver Your Presentation
Broadcast and compress for seamless delivery
raquo Show and tell your presentation with Broadcast Slide Show
raquo Share your presentation in real-time with anyone with a browser directly from PowerPoint
raquo Yoursquoll never have to say ldquoNext slide pleaserdquo again
BROADCAST IT
Record your presentation with Create a Video and capture narrations
animations media and much more
Upload embed and share away
SPEAK FOR ITSELFLet Your Presentation
But waithellip Therersquos More
View your slides from anywhere
raquo Check out the PowerPoint Web App
raquo Access slides wherever you are
Access Anywhere
Whatrsquos Your MessagePOWERPOINT 2010
The abdominal circumference (AC) is a transverse section (coronal) through the fetal abdomen at the level where the umbilical vein enters the liver The AC may be measured directly or calculated from the AP and transverse abdominal measurements Both techniques give good results Although the AC can be used to calculate gestational age it is more useful in determining fetal weight Combined with the BPD with or without the fetal femur length reliable formulas can be used to predict fetal weight
Level I and Level II Scanning (Screening vs Targeted Scanning)Level I (screening) scanning consists of the basic evaluation listed above It is usually relatively simple to perform readily available and relatively inexpensive More detailed scanning (Level II or targeted scan) requires higher resolution (more expensive) equipment and sonographic skills that are more limited in their availablity and significantly more expensive Indications for a Level II scan may includeSuspicious findings on a Level I scanHistory of prior congenital anomalyInsulin dependent diabetes or other medical problem that increases the risk of anomalyHistory of seizure disorder particularly if being treated with medications known to increase the risk of anomalyTeratogen exposureElevated MSAFPSuspected chromosome abnormalitySymmetric IUGRFetal arrhythmiaOligohydramnios hydramniosAdvanced maternal age
- IMAGING IN OBSTETRICS amp GYNAECOLOGY
- ULTRASOUND IN OBSTETRICS
- Slide 3
- HCG Levels for normal Pregnancy NOTE The quantitative matern
- 1st TRIMESTER SCAN
- Slide 6
- GESTATIONAL SAC
- Slide 8
- YOLK SAC
- Slide 10
- Slide 11
- Slide 12
- DOUBLE DECIDUAL SIGN
- Slide 14
- DOUBLE BLEB SIGN
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- 8 weeks
- NOTE- Demarcation between the Chorion amp Amnion
- NUCHAL TRANSLUCENCY
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- abortions
- MISSED ABORTION
- Slide 41
- INEVITABLE ABORTION
- THREATENED ABORTION
- Slide 44
- Slide 45
- COMPLETE ABORTION
- INCOMPLETE ABORTION
- BLIGHTED OVUM
- Slide 49
- Slide 50
- Slide 51
- Slide 52
- LOCATIONS
- Slide 54
- TUBAL ECTOPIC PREGNANCY
- The presence of Ring of Fire sign confirms the anechoic shado
- 2ND amp 3rd TRIMESTER SCANNING
- Slide 58
- Slide 59
- Slide 60
- FETAL SKULL
- Slide 62
- BI-PARIETAL DIAMETRE
- Slide 64
- LIMITATIONS
- Slide 66
- Slide 67
- TRANS CEREBELLAR DIAMETER
- TCD
- HEAD CIRCUMFERENCE
- ANENCEPHALY
- Slide 72
- HYDROCEPHALUS
- Slide 74
- Slide 75
- Holoprosencephaly (HPE)
- Slide 77
- Slide 78
- ALOBAR HOLOPROSENCEPHALY
- LOBAR PROSENCEPHALY
- SEMI-LOBAR HOLOPROSENCEPHALY
- SEMILOBAR HOLOPROSENCEPHALY
- HYDRENCEPHALY
- DANDY WALKER CONTINUUM
- Slide 85
- Slide 86
- Slide 87
- Slide 88
- ARNOLD CHIARI TYPE-2 MALFORMATION
- Slide 90
- Slide 91
- BANANA CEREBELLUM SIGN
- Slide 93
- Slide 94
- LEMON HEAD SIGN
- ABNORMAL SKULL SHAPES
- Slide 97
- NUCHAL THICKNESS
- Slide 99
- Slide 100
- Slide 101
- Slide 102
- Slide 103
- Slide 104
- FETAL FACE
- Slide 106
- Slide 107
- Slide 108
- 3-D IMAGE OF THE FACE
- Slide 110
- Slide 111
- Slide 112
- FETAL THORAX
- Slide 114
- Slide 115
- Slide 116
- Fountain Geyser
- What about the beautiful transitions yoursquove been seeing
- Deliver Your Presentation
- Slide 120
- SPEAK FOR ITSELF
- But waithellip Therersquos More
- Access Anywhere
- Slide 124
- Slide 125
- Slide 126
-
raquo Show and tell your presentation with Broadcast Slide Show
raquo Share your presentation in real-time with anyone with a browser directly from PowerPoint
raquo Yoursquoll never have to say ldquoNext slide pleaserdquo again
BROADCAST IT
Record your presentation with Create a Video and capture narrations
animations media and much more
Upload embed and share away
SPEAK FOR ITSELFLet Your Presentation
But waithellip Therersquos More
View your slides from anywhere
raquo Check out the PowerPoint Web App
raquo Access slides wherever you are
Access Anywhere
Whatrsquos Your MessagePOWERPOINT 2010
The abdominal circumference (AC) is a transverse section (coronal) through the fetal abdomen at the level where the umbilical vein enters the liver The AC may be measured directly or calculated from the AP and transverse abdominal measurements Both techniques give good results Although the AC can be used to calculate gestational age it is more useful in determining fetal weight Combined with the BPD with or without the fetal femur length reliable formulas can be used to predict fetal weight
Level I and Level II Scanning (Screening vs Targeted Scanning)Level I (screening) scanning consists of the basic evaluation listed above It is usually relatively simple to perform readily available and relatively inexpensive More detailed scanning (Level II or targeted scan) requires higher resolution (more expensive) equipment and sonographic skills that are more limited in their availablity and significantly more expensive Indications for a Level II scan may includeSuspicious findings on a Level I scanHistory of prior congenital anomalyInsulin dependent diabetes or other medical problem that increases the risk of anomalyHistory of seizure disorder particularly if being treated with medications known to increase the risk of anomalyTeratogen exposureElevated MSAFPSuspected chromosome abnormalitySymmetric IUGRFetal arrhythmiaOligohydramnios hydramniosAdvanced maternal age
- IMAGING IN OBSTETRICS amp GYNAECOLOGY
- ULTRASOUND IN OBSTETRICS
- Slide 3
- HCG Levels for normal Pregnancy NOTE The quantitative matern
- 1st TRIMESTER SCAN
- Slide 6
- GESTATIONAL SAC
- Slide 8
- YOLK SAC
- Slide 10
- Slide 11
- Slide 12
- DOUBLE DECIDUAL SIGN
- Slide 14
- DOUBLE BLEB SIGN
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- 8 weeks
- NOTE- Demarcation between the Chorion amp Amnion
- NUCHAL TRANSLUCENCY
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- abortions
- MISSED ABORTION
- Slide 41
- INEVITABLE ABORTION
- THREATENED ABORTION
- Slide 44
- Slide 45
- COMPLETE ABORTION
- INCOMPLETE ABORTION
- BLIGHTED OVUM
- Slide 49
- Slide 50
- Slide 51
- Slide 52
- LOCATIONS
- Slide 54
- TUBAL ECTOPIC PREGNANCY
- The presence of Ring of Fire sign confirms the anechoic shado
- 2ND amp 3rd TRIMESTER SCANNING
- Slide 58
- Slide 59
- Slide 60
- FETAL SKULL
- Slide 62
- BI-PARIETAL DIAMETRE
- Slide 64
- LIMITATIONS
- Slide 66
- Slide 67
- TRANS CEREBELLAR DIAMETER
- TCD
- HEAD CIRCUMFERENCE
- ANENCEPHALY
- Slide 72
- HYDROCEPHALUS
- Slide 74
- Slide 75
- Holoprosencephaly (HPE)
- Slide 77
- Slide 78
- ALOBAR HOLOPROSENCEPHALY
- LOBAR PROSENCEPHALY
- SEMI-LOBAR HOLOPROSENCEPHALY
- SEMILOBAR HOLOPROSENCEPHALY
- HYDRENCEPHALY
- DANDY WALKER CONTINUUM
- Slide 85
- Slide 86
- Slide 87
- Slide 88
- ARNOLD CHIARI TYPE-2 MALFORMATION
- Slide 90
- Slide 91
- BANANA CEREBELLUM SIGN
- Slide 93
- Slide 94
- LEMON HEAD SIGN
- ABNORMAL SKULL SHAPES
- Slide 97
- NUCHAL THICKNESS
- Slide 99
- Slide 100
- Slide 101
- Slide 102
- Slide 103
- Slide 104
- FETAL FACE
- Slide 106
- Slide 107
- Slide 108
- 3-D IMAGE OF THE FACE
- Slide 110
- Slide 111
- Slide 112
- FETAL THORAX
- Slide 114
- Slide 115
- Slide 116
- Fountain Geyser
- What about the beautiful transitions yoursquove been seeing
- Deliver Your Presentation
- Slide 120
- SPEAK FOR ITSELF
- But waithellip Therersquos More
- Access Anywhere
- Slide 124
- Slide 125
- Slide 126
-
Record your presentation with Create a Video and capture narrations
animations media and much more
Upload embed and share away
SPEAK FOR ITSELFLet Your Presentation
But waithellip Therersquos More
View your slides from anywhere
raquo Check out the PowerPoint Web App
raquo Access slides wherever you are
Access Anywhere
Whatrsquos Your MessagePOWERPOINT 2010
The abdominal circumference (AC) is a transverse section (coronal) through the fetal abdomen at the level where the umbilical vein enters the liver The AC may be measured directly or calculated from the AP and transverse abdominal measurements Both techniques give good results Although the AC can be used to calculate gestational age it is more useful in determining fetal weight Combined with the BPD with or without the fetal femur length reliable formulas can be used to predict fetal weight
Level I and Level II Scanning (Screening vs Targeted Scanning)Level I (screening) scanning consists of the basic evaluation listed above It is usually relatively simple to perform readily available and relatively inexpensive More detailed scanning (Level II or targeted scan) requires higher resolution (more expensive) equipment and sonographic skills that are more limited in their availablity and significantly more expensive Indications for a Level II scan may includeSuspicious findings on a Level I scanHistory of prior congenital anomalyInsulin dependent diabetes or other medical problem that increases the risk of anomalyHistory of seizure disorder particularly if being treated with medications known to increase the risk of anomalyTeratogen exposureElevated MSAFPSuspected chromosome abnormalitySymmetric IUGRFetal arrhythmiaOligohydramnios hydramniosAdvanced maternal age
- IMAGING IN OBSTETRICS amp GYNAECOLOGY
- ULTRASOUND IN OBSTETRICS
- Slide 3
- HCG Levels for normal Pregnancy NOTE The quantitative matern
- 1st TRIMESTER SCAN
- Slide 6
- GESTATIONAL SAC
- Slide 8
- YOLK SAC
- Slide 10
- Slide 11
- Slide 12
- DOUBLE DECIDUAL SIGN
- Slide 14
- DOUBLE BLEB SIGN
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- 8 weeks
- NOTE- Demarcation between the Chorion amp Amnion
- NUCHAL TRANSLUCENCY
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- abortions
- MISSED ABORTION
- Slide 41
- INEVITABLE ABORTION
- THREATENED ABORTION
- Slide 44
- Slide 45
- COMPLETE ABORTION
- INCOMPLETE ABORTION
- BLIGHTED OVUM
- Slide 49
- Slide 50
- Slide 51
- Slide 52
- LOCATIONS
- Slide 54
- TUBAL ECTOPIC PREGNANCY
- The presence of Ring of Fire sign confirms the anechoic shado
- 2ND amp 3rd TRIMESTER SCANNING
- Slide 58
- Slide 59
- Slide 60
- FETAL SKULL
- Slide 62
- BI-PARIETAL DIAMETRE
- Slide 64
- LIMITATIONS
- Slide 66
- Slide 67
- TRANS CEREBELLAR DIAMETER
- TCD
- HEAD CIRCUMFERENCE
- ANENCEPHALY
- Slide 72
- HYDROCEPHALUS
- Slide 74
- Slide 75
- Holoprosencephaly (HPE)
- Slide 77
- Slide 78
- ALOBAR HOLOPROSENCEPHALY
- LOBAR PROSENCEPHALY
- SEMI-LOBAR HOLOPROSENCEPHALY
- SEMILOBAR HOLOPROSENCEPHALY
- HYDRENCEPHALY
- DANDY WALKER CONTINUUM
- Slide 85
- Slide 86
- Slide 87
- Slide 88
- ARNOLD CHIARI TYPE-2 MALFORMATION
- Slide 90
- Slide 91
- BANANA CEREBELLUM SIGN
- Slide 93
- Slide 94
- LEMON HEAD SIGN
- ABNORMAL SKULL SHAPES
- Slide 97
- NUCHAL THICKNESS
- Slide 99
- Slide 100
- Slide 101
- Slide 102
- Slide 103
- Slide 104
- FETAL FACE
- Slide 106
- Slide 107
- Slide 108
- 3-D IMAGE OF THE FACE
- Slide 110
- Slide 111
- Slide 112
- FETAL THORAX
- Slide 114
- Slide 115
- Slide 116
- Fountain Geyser
- What about the beautiful transitions yoursquove been seeing
- Deliver Your Presentation
- Slide 120
- SPEAK FOR ITSELF
- But waithellip Therersquos More
- Access Anywhere
- Slide 124
- Slide 125
- Slide 126
-
But waithellip Therersquos More
View your slides from anywhere
raquo Check out the PowerPoint Web App
raquo Access slides wherever you are
Access Anywhere
Whatrsquos Your MessagePOWERPOINT 2010
The abdominal circumference (AC) is a transverse section (coronal) through the fetal abdomen at the level where the umbilical vein enters the liver The AC may be measured directly or calculated from the AP and transverse abdominal measurements Both techniques give good results Although the AC can be used to calculate gestational age it is more useful in determining fetal weight Combined with the BPD with or without the fetal femur length reliable formulas can be used to predict fetal weight
Level I and Level II Scanning (Screening vs Targeted Scanning)Level I (screening) scanning consists of the basic evaluation listed above It is usually relatively simple to perform readily available and relatively inexpensive More detailed scanning (Level II or targeted scan) requires higher resolution (more expensive) equipment and sonographic skills that are more limited in their availablity and significantly more expensive Indications for a Level II scan may includeSuspicious findings on a Level I scanHistory of prior congenital anomalyInsulin dependent diabetes or other medical problem that increases the risk of anomalyHistory of seizure disorder particularly if being treated with medications known to increase the risk of anomalyTeratogen exposureElevated MSAFPSuspected chromosome abnormalitySymmetric IUGRFetal arrhythmiaOligohydramnios hydramniosAdvanced maternal age
- IMAGING IN OBSTETRICS amp GYNAECOLOGY
- ULTRASOUND IN OBSTETRICS
- Slide 3
- HCG Levels for normal Pregnancy NOTE The quantitative matern
- 1st TRIMESTER SCAN
- Slide 6
- GESTATIONAL SAC
- Slide 8
- YOLK SAC
- Slide 10
- Slide 11
- Slide 12
- DOUBLE DECIDUAL SIGN
- Slide 14
- DOUBLE BLEB SIGN
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- 8 weeks
- NOTE- Demarcation between the Chorion amp Amnion
- NUCHAL TRANSLUCENCY
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- abortions
- MISSED ABORTION
- Slide 41
- INEVITABLE ABORTION
- THREATENED ABORTION
- Slide 44
- Slide 45
- COMPLETE ABORTION
- INCOMPLETE ABORTION
- BLIGHTED OVUM
- Slide 49
- Slide 50
- Slide 51
- Slide 52
- LOCATIONS
- Slide 54
- TUBAL ECTOPIC PREGNANCY
- The presence of Ring of Fire sign confirms the anechoic shado
- 2ND amp 3rd TRIMESTER SCANNING
- Slide 58
- Slide 59
- Slide 60
- FETAL SKULL
- Slide 62
- BI-PARIETAL DIAMETRE
- Slide 64
- LIMITATIONS
- Slide 66
- Slide 67
- TRANS CEREBELLAR DIAMETER
- TCD
- HEAD CIRCUMFERENCE
- ANENCEPHALY
- Slide 72
- HYDROCEPHALUS
- Slide 74
- Slide 75
- Holoprosencephaly (HPE)
- Slide 77
- Slide 78
- ALOBAR HOLOPROSENCEPHALY
- LOBAR PROSENCEPHALY
- SEMI-LOBAR HOLOPROSENCEPHALY
- SEMILOBAR HOLOPROSENCEPHALY
- HYDRENCEPHALY
- DANDY WALKER CONTINUUM
- Slide 85
- Slide 86
- Slide 87
- Slide 88
- ARNOLD CHIARI TYPE-2 MALFORMATION
- Slide 90
- Slide 91
- BANANA CEREBELLUM SIGN
- Slide 93
- Slide 94
- LEMON HEAD SIGN
- ABNORMAL SKULL SHAPES
- Slide 97
- NUCHAL THICKNESS
- Slide 99
- Slide 100
- Slide 101
- Slide 102
- Slide 103
- Slide 104
- FETAL FACE
- Slide 106
- Slide 107
- Slide 108
- 3-D IMAGE OF THE FACE
- Slide 110
- Slide 111
- Slide 112
- FETAL THORAX
- Slide 114
- Slide 115
- Slide 116
- Fountain Geyser
- What about the beautiful transitions yoursquove been seeing
- Deliver Your Presentation
- Slide 120
- SPEAK FOR ITSELF
- But waithellip Therersquos More
- Access Anywhere
- Slide 124
- Slide 125
- Slide 126
-
raquo Check out the PowerPoint Web App
raquo Access slides wherever you are
Access Anywhere
Whatrsquos Your MessagePOWERPOINT 2010
The abdominal circumference (AC) is a transverse section (coronal) through the fetal abdomen at the level where the umbilical vein enters the liver The AC may be measured directly or calculated from the AP and transverse abdominal measurements Both techniques give good results Although the AC can be used to calculate gestational age it is more useful in determining fetal weight Combined with the BPD with or without the fetal femur length reliable formulas can be used to predict fetal weight
Level I and Level II Scanning (Screening vs Targeted Scanning)Level I (screening) scanning consists of the basic evaluation listed above It is usually relatively simple to perform readily available and relatively inexpensive More detailed scanning (Level II or targeted scan) requires higher resolution (more expensive) equipment and sonographic skills that are more limited in their availablity and significantly more expensive Indications for a Level II scan may includeSuspicious findings on a Level I scanHistory of prior congenital anomalyInsulin dependent diabetes or other medical problem that increases the risk of anomalyHistory of seizure disorder particularly if being treated with medications known to increase the risk of anomalyTeratogen exposureElevated MSAFPSuspected chromosome abnormalitySymmetric IUGRFetal arrhythmiaOligohydramnios hydramniosAdvanced maternal age
- IMAGING IN OBSTETRICS amp GYNAECOLOGY
- ULTRASOUND IN OBSTETRICS
- Slide 3
- HCG Levels for normal Pregnancy NOTE The quantitative matern
- 1st TRIMESTER SCAN
- Slide 6
- GESTATIONAL SAC
- Slide 8
- YOLK SAC
- Slide 10
- Slide 11
- Slide 12
- DOUBLE DECIDUAL SIGN
- Slide 14
- DOUBLE BLEB SIGN
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- 8 weeks
- NOTE- Demarcation between the Chorion amp Amnion
- NUCHAL TRANSLUCENCY
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- abortions
- MISSED ABORTION
- Slide 41
- INEVITABLE ABORTION
- THREATENED ABORTION
- Slide 44
- Slide 45
- COMPLETE ABORTION
- INCOMPLETE ABORTION
- BLIGHTED OVUM
- Slide 49
- Slide 50
- Slide 51
- Slide 52
- LOCATIONS
- Slide 54
- TUBAL ECTOPIC PREGNANCY
- The presence of Ring of Fire sign confirms the anechoic shado
- 2ND amp 3rd TRIMESTER SCANNING
- Slide 58
- Slide 59
- Slide 60
- FETAL SKULL
- Slide 62
- BI-PARIETAL DIAMETRE
- Slide 64
- LIMITATIONS
- Slide 66
- Slide 67
- TRANS CEREBELLAR DIAMETER
- TCD
- HEAD CIRCUMFERENCE
- ANENCEPHALY
- Slide 72
- HYDROCEPHALUS
- Slide 74
- Slide 75
- Holoprosencephaly (HPE)
- Slide 77
- Slide 78
- ALOBAR HOLOPROSENCEPHALY
- LOBAR PROSENCEPHALY
- SEMI-LOBAR HOLOPROSENCEPHALY
- SEMILOBAR HOLOPROSENCEPHALY
- HYDRENCEPHALY
- DANDY WALKER CONTINUUM
- Slide 85
- Slide 86
- Slide 87
- Slide 88
- ARNOLD CHIARI TYPE-2 MALFORMATION
- Slide 90
- Slide 91
- BANANA CEREBELLUM SIGN
- Slide 93
- Slide 94
- LEMON HEAD SIGN
- ABNORMAL SKULL SHAPES
- Slide 97
- NUCHAL THICKNESS
- Slide 99
- Slide 100
- Slide 101
- Slide 102
- Slide 103
- Slide 104
- FETAL FACE
- Slide 106
- Slide 107
- Slide 108
- 3-D IMAGE OF THE FACE
- Slide 110
- Slide 111
- Slide 112
- FETAL THORAX
- Slide 114
- Slide 115
- Slide 116
- Fountain Geyser
- What about the beautiful transitions yoursquove been seeing
- Deliver Your Presentation
- Slide 120
- SPEAK FOR ITSELF
- But waithellip Therersquos More
- Access Anywhere
- Slide 124
- Slide 125
- Slide 126
-
Whatrsquos Your MessagePOWERPOINT 2010
The abdominal circumference (AC) is a transverse section (coronal) through the fetal abdomen at the level where the umbilical vein enters the liver The AC may be measured directly or calculated from the AP and transverse abdominal measurements Both techniques give good results Although the AC can be used to calculate gestational age it is more useful in determining fetal weight Combined with the BPD with or without the fetal femur length reliable formulas can be used to predict fetal weight
Level I and Level II Scanning (Screening vs Targeted Scanning)Level I (screening) scanning consists of the basic evaluation listed above It is usually relatively simple to perform readily available and relatively inexpensive More detailed scanning (Level II or targeted scan) requires higher resolution (more expensive) equipment and sonographic skills that are more limited in their availablity and significantly more expensive Indications for a Level II scan may includeSuspicious findings on a Level I scanHistory of prior congenital anomalyInsulin dependent diabetes or other medical problem that increases the risk of anomalyHistory of seizure disorder particularly if being treated with medications known to increase the risk of anomalyTeratogen exposureElevated MSAFPSuspected chromosome abnormalitySymmetric IUGRFetal arrhythmiaOligohydramnios hydramniosAdvanced maternal age
- IMAGING IN OBSTETRICS amp GYNAECOLOGY
- ULTRASOUND IN OBSTETRICS
- Slide 3
- HCG Levels for normal Pregnancy NOTE The quantitative matern
- 1st TRIMESTER SCAN
- Slide 6
- GESTATIONAL SAC
- Slide 8
- YOLK SAC
- Slide 10
- Slide 11
- Slide 12
- DOUBLE DECIDUAL SIGN
- Slide 14
- DOUBLE BLEB SIGN
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- 8 weeks
- NOTE- Demarcation between the Chorion amp Amnion
- NUCHAL TRANSLUCENCY
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- abortions
- MISSED ABORTION
- Slide 41
- INEVITABLE ABORTION
- THREATENED ABORTION
- Slide 44
- Slide 45
- COMPLETE ABORTION
- INCOMPLETE ABORTION
- BLIGHTED OVUM
- Slide 49
- Slide 50
- Slide 51
- Slide 52
- LOCATIONS
- Slide 54
- TUBAL ECTOPIC PREGNANCY
- The presence of Ring of Fire sign confirms the anechoic shado
- 2ND amp 3rd TRIMESTER SCANNING
- Slide 58
- Slide 59
- Slide 60
- FETAL SKULL
- Slide 62
- BI-PARIETAL DIAMETRE
- Slide 64
- LIMITATIONS
- Slide 66
- Slide 67
- TRANS CEREBELLAR DIAMETER
- TCD
- HEAD CIRCUMFERENCE
- ANENCEPHALY
- Slide 72
- HYDROCEPHALUS
- Slide 74
- Slide 75
- Holoprosencephaly (HPE)
- Slide 77
- Slide 78
- ALOBAR HOLOPROSENCEPHALY
- LOBAR PROSENCEPHALY
- SEMI-LOBAR HOLOPROSENCEPHALY
- SEMILOBAR HOLOPROSENCEPHALY
- HYDRENCEPHALY
- DANDY WALKER CONTINUUM
- Slide 85
- Slide 86
- Slide 87
- Slide 88
- ARNOLD CHIARI TYPE-2 MALFORMATION
- Slide 90
- Slide 91
- BANANA CEREBELLUM SIGN
- Slide 93
- Slide 94
- LEMON HEAD SIGN
- ABNORMAL SKULL SHAPES
- Slide 97
- NUCHAL THICKNESS
- Slide 99
- Slide 100
- Slide 101
- Slide 102
- Slide 103
- Slide 104
- FETAL FACE
- Slide 106
- Slide 107
- Slide 108
- 3-D IMAGE OF THE FACE
- Slide 110
- Slide 111
- Slide 112
- FETAL THORAX
- Slide 114
- Slide 115
- Slide 116
- Fountain Geyser
- What about the beautiful transitions yoursquove been seeing
- Deliver Your Presentation
- Slide 120
- SPEAK FOR ITSELF
- But waithellip Therersquos More
- Access Anywhere
- Slide 124
- Slide 125
- Slide 126
-
The abdominal circumference (AC) is a transverse section (coronal) through the fetal abdomen at the level where the umbilical vein enters the liver The AC may be measured directly or calculated from the AP and transverse abdominal measurements Both techniques give good results Although the AC can be used to calculate gestational age it is more useful in determining fetal weight Combined with the BPD with or without the fetal femur length reliable formulas can be used to predict fetal weight
Level I and Level II Scanning (Screening vs Targeted Scanning)Level I (screening) scanning consists of the basic evaluation listed above It is usually relatively simple to perform readily available and relatively inexpensive More detailed scanning (Level II or targeted scan) requires higher resolution (more expensive) equipment and sonographic skills that are more limited in their availablity and significantly more expensive Indications for a Level II scan may includeSuspicious findings on a Level I scanHistory of prior congenital anomalyInsulin dependent diabetes or other medical problem that increases the risk of anomalyHistory of seizure disorder particularly if being treated with medications known to increase the risk of anomalyTeratogen exposureElevated MSAFPSuspected chromosome abnormalitySymmetric IUGRFetal arrhythmiaOligohydramnios hydramniosAdvanced maternal age
- IMAGING IN OBSTETRICS amp GYNAECOLOGY
- ULTRASOUND IN OBSTETRICS
- Slide 3
- HCG Levels for normal Pregnancy NOTE The quantitative matern
- 1st TRIMESTER SCAN
- Slide 6
- GESTATIONAL SAC
- Slide 8
- YOLK SAC
- Slide 10
- Slide 11
- Slide 12
- DOUBLE DECIDUAL SIGN
- Slide 14
- DOUBLE BLEB SIGN
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- 8 weeks
- NOTE- Demarcation between the Chorion amp Amnion
- NUCHAL TRANSLUCENCY
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- abortions
- MISSED ABORTION
- Slide 41
- INEVITABLE ABORTION
- THREATENED ABORTION
- Slide 44
- Slide 45
- COMPLETE ABORTION
- INCOMPLETE ABORTION
- BLIGHTED OVUM
- Slide 49
- Slide 50
- Slide 51
- Slide 52
- LOCATIONS
- Slide 54
- TUBAL ECTOPIC PREGNANCY
- The presence of Ring of Fire sign confirms the anechoic shado
- 2ND amp 3rd TRIMESTER SCANNING
- Slide 58
- Slide 59
- Slide 60
- FETAL SKULL
- Slide 62
- BI-PARIETAL DIAMETRE
- Slide 64
- LIMITATIONS
- Slide 66
- Slide 67
- TRANS CEREBELLAR DIAMETER
- TCD
- HEAD CIRCUMFERENCE
- ANENCEPHALY
- Slide 72
- HYDROCEPHALUS
- Slide 74
- Slide 75
- Holoprosencephaly (HPE)
- Slide 77
- Slide 78
- ALOBAR HOLOPROSENCEPHALY
- LOBAR PROSENCEPHALY
- SEMI-LOBAR HOLOPROSENCEPHALY
- SEMILOBAR HOLOPROSENCEPHALY
- HYDRENCEPHALY
- DANDY WALKER CONTINUUM
- Slide 85
- Slide 86
- Slide 87
- Slide 88
- ARNOLD CHIARI TYPE-2 MALFORMATION
- Slide 90
- Slide 91
- BANANA CEREBELLUM SIGN
- Slide 93
- Slide 94
- LEMON HEAD SIGN
- ABNORMAL SKULL SHAPES
- Slide 97
- NUCHAL THICKNESS
- Slide 99
- Slide 100
- Slide 101
- Slide 102
- Slide 103
- Slide 104
- FETAL FACE
- Slide 106
- Slide 107
- Slide 108
- 3-D IMAGE OF THE FACE
- Slide 110
- Slide 111
- Slide 112
- FETAL THORAX
- Slide 114
- Slide 115
- Slide 116
- Fountain Geyser
- What about the beautiful transitions yoursquove been seeing
- Deliver Your Presentation
- Slide 120
- SPEAK FOR ITSELF
- But waithellip Therersquos More
- Access Anywhere
- Slide 124
- Slide 125
- Slide 126
-
- IMAGING IN OBSTETRICS amp GYNAECOLOGY
- ULTRASOUND IN OBSTETRICS
- Slide 3
- HCG Levels for normal Pregnancy NOTE The quantitative matern
- 1st TRIMESTER SCAN
- Slide 6
- GESTATIONAL SAC
- Slide 8
- YOLK SAC
- Slide 10
- Slide 11
- Slide 12
- DOUBLE DECIDUAL SIGN
- Slide 14
- DOUBLE BLEB SIGN
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- 8 weeks
- NOTE- Demarcation between the Chorion amp Amnion
- NUCHAL TRANSLUCENCY
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- abortions
- MISSED ABORTION
- Slide 41
- INEVITABLE ABORTION
- THREATENED ABORTION
- Slide 44
- Slide 45
- COMPLETE ABORTION
- INCOMPLETE ABORTION
- BLIGHTED OVUM
- Slide 49
- Slide 50
- Slide 51
- Slide 52
- LOCATIONS
- Slide 54
- TUBAL ECTOPIC PREGNANCY
- The presence of Ring of Fire sign confirms the anechoic shado
- 2ND amp 3rd TRIMESTER SCANNING
- Slide 58
- Slide 59
- Slide 60
- FETAL SKULL
- Slide 62
- BI-PARIETAL DIAMETRE
- Slide 64
- LIMITATIONS
- Slide 66
- Slide 67
- TRANS CEREBELLAR DIAMETER
- TCD
- HEAD CIRCUMFERENCE
- ANENCEPHALY
- Slide 72
- HYDROCEPHALUS
- Slide 74
- Slide 75
- Holoprosencephaly (HPE)
- Slide 77
- Slide 78
- ALOBAR HOLOPROSENCEPHALY
- LOBAR PROSENCEPHALY
- SEMI-LOBAR HOLOPROSENCEPHALY
- SEMILOBAR HOLOPROSENCEPHALY
- HYDRENCEPHALY
- DANDY WALKER CONTINUUM
- Slide 85
- Slide 86
- Slide 87
- Slide 88
- ARNOLD CHIARI TYPE-2 MALFORMATION
- Slide 90
- Slide 91
- BANANA CEREBELLUM SIGN
- Slide 93
- Slide 94
- LEMON HEAD SIGN
- ABNORMAL SKULL SHAPES
- Slide 97
- NUCHAL THICKNESS
- Slide 99
- Slide 100
- Slide 101
- Slide 102
- Slide 103
- Slide 104
- FETAL FACE
- Slide 106
- Slide 107
- Slide 108
- 3-D IMAGE OF THE FACE
- Slide 110
- Slide 111
- Slide 112
- FETAL THORAX
- Slide 114
- Slide 115
- Slide 116
- Fountain Geyser
- What about the beautiful transitions yoursquove been seeing
- Deliver Your Presentation
- Slide 120
- SPEAK FOR ITSELF
- But waithellip Therersquos More
- Access Anywhere
- Slide 124
- Slide 125
- Slide 126
-
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