Ultrasound of Thyroid,parathyroid glands and neck lymph nodes Presenter : Dr.Sanjeeva Rao Moderator : Dr.Kishore.V.H Prof&HOD,Dept of Radiology NMCH. NELLORE
Ultrasound of Thyroid,parathyroid glands
and neck lymph nodes
Presenter : Dr.Sanjeeva Rao
Moderator : Dr.Kishore.V.HProf&HOD,Dept of Radiology
NMCH. NELLORE
EMBRYOLOGY First appears late in the 4th week of embryonic life as a
nodule of endoderm at the apex of the foramen caecum on the developing tounge
This nodule descends through the neck at the end of a slender thyroglossal duct, which breakdown by the end of 5th week
The thyroid continues its descent to reach its definitive position by the 7th week
Located in the anteroinferior part of neck (infrahyod compartment) outlined by muscle,trachea,esophagus,carotid arteries and jugular veins.
Extends from C-5 through T-1The thyroid gland is made up of two lobes
located along either side of the trachea and connected across the midline by the Isthmus
10-40% of normal patients have a small pyramidal lobe arising superiorly from the isthmus
supplied by R&L inferior thyroid artery,R&L superior thyroid artery .Drained by R & L superior, middle and inferior thyroid
veins
Muscular landmarks
a. Sternocleidomastoid muscles lie laterally
b. Longus colli (prevertebral)muscles lie posteriorly
c. “Strap” muscles lie anteriorly In adults mean length is 40 to 60 mm and the mean
anteroposterior diameter is 13 to18 mm. thickness of isthmus is 4 to 6 mm
Ultrasound of normal thyroid
Normal appearing thyroid in transverse view. Thyroid ishomogeneous and slightly hyperechoic. The lobes are bordered anteriorlyby the strap muscles (SM), posteriorly by the longus colli muscle(LC), medially by the trachea, and laterally by the sternocleidomastoidmuscle (SCM), carotid artery and jugular vein. A portion of the esophagus(ESO) protrudes behind the tracheal shadow against the medial borderof the left lobe
Ultrasound technique(High frequency trancducers:7.5to15.0MHz)
Patients are usually scanned in the supine position with the neck mildly hyperextended by an pillow
Both lobes are scanned individually in the transverse and in the longitudinal plane
Any specific abnormalities should be studied in both planes by rotating the transducer 90 degrees over the area
If the lobe is longer than the transducer, a “split screen technique” can be used to measure the length of lobe
Measurement of the thyroid (or a nodule) involves three measurements: the width, depth and length
THYROID ANOMALIES
Hemiagenesis of the thyroid
Aberrant Thyroid
Thyroglossal Duct cyst
THYROID ANOMALIES
Hemiagenesis of the thyroid
It is usually found when ultrasound is being done for some other cause, such as evaluation of a nodule in the contralateral lobe
Hemiagenesis of the left lobe. Ultrasound done to evaluatethe palpable nodule (N) in the right lobe reveals the thyroid ends atthe isthmus (arrow). The strap muscles (SM) have filled in the spacewhere the left lobe would be. Physical examination of the left neckwas normal
THYROID ANOMALIESAberrant Thyroid
can occur anywhere along the path of descent most common at the base of the tongue ‘lingual thyroid’
Resulting from failed bifurcation of two lobes
Failed bifurcation of the thyroid. This patient presented with an apparent “goiter” located 1 cm above the larynx. Ultrasound reveals a normal amount of thyroid tissue, and thyroid function was normal
THYROID ANOMALIES
Thyroglossal Duct cystSometimes the entire
thyroglossal duct persists, and protein material secreted by the lining epithelium may form a thyroglossal duct cyst that manifests itself clinically as a midline mass in the anterior aspect of the neck above the isthmus.
can form a sinusFluid filled Thyroglossal duct cyst in the midline.
Muscle anomaly
Patient was thought to have a nodule in the right lobe by physical examination. Ultrasound revealed enlargement of the strap muscle in the right neck (arrow) causing asymmetry; no nodule is present
Thyroid pathologies NODULAR DESEASES:
Goiter/hyperplasia , Thyroid adenoma , Thyroid malignancy( Papillary ca,Follicular ca, Anaplastic ca,Medullary ca,Thyroid primary lymphoma)
DIFFUSE DESEASES: Graves’ disease, acute suppurative thyroiditis,subacute(De Quervain)thyroiditis ,Chronic autoimmune thyroiditis,Silent thyroiditis,Riedels thyroiditis
NODLAR DISEASES
In thyroid nodular deseases sonography has five major applications;
1)Detection of nodules
2)Deffrentiation of goiter/hyperplasia from other thyroid nodular deseases
3)Preoperative determination of the extent of known thyroid malignancy
4)Detection of residual,recurrence
5)Guidance of FNAC for nan palpable nodules
Each thyroid nodule has to be studied :Echogenicity compared with normal
parenchymaPresence calcifiacations/cystic changesPattern of marginsPresence of echo-poor haloAmont and distribution of blood flow
Goiter/hyperplasia80% of nodular desease is due to hyperplasiaWhen single or multiple hyperplastic nodules
lead to global enlargement of the gland the term Goiter is used(either single or multinodular)
Sonographically; most hyperplastic nodules are Isoechoic with well defined margins
Cystic changes are present in 60-70% of cases
Typical comet tail artefacts seen with in nodules
Macro calcifications are present in “old”nodules These Calcificatoins are typicallycurvilinear, annular or dismorphic with posterior shadowing
Doppler:
- usually less vascularised than normal parenchyma
-Exception of rapidly growing hyperplastic lesions in yong patients
Isoechoic with thin regular halo cystic with multiple comet-tail artefacts and small internal cystic change
AdenomaRepresents 5-10% of all nodular deseaseCommon in femalesVarious subtypes of Follicular adenoma
1.Fetal adenoma 2.Hurthle cell adenoma 3.Embryonal adenoma
Sonography:
>commonly solid masses
>May be hypoechoic,isoechoic or hyperechoic
>Thick and smooth hypoechoic halo
Doppler imaging:
>blood flow from perifery to the center of the nodule called”Spoke and wheel” appearance
Thyroid adenoma shows peripheral
Vascularity with Spoke and wheel appearance
,blood flow towards the centre of the mass
Thyroid malignancyPapillary carcinoma
Most common thyroid malignancy(60-70%)Common in females ,Slow growth and good prognosisSonography: >Hypoechogenicity
>Intralesional punctate calcifications
>Hypervascularity
>Cerivical lymph node metastases which contain punctate microcalcifications
Follicular carcinomaAccounts for 5-15% of thyroid cancersAssociated with hyperplastic/adenomatous
thyroid nodules in 60-70% of casesSignificant criteria: Capsular & vascular invasionSonography: solid,homogenous, hyperechoic or isoechoic Thick irregular capsule,tortuous perinodular and
intranodular blood vessels….signs of extra capsular spread
Isoechogenicity,perilesional and internal blood suply features of Follicular carcinoma
Anaplastic carcinomaRepresents 5-10% of all thyroid carcinomasMostly occurs in elderyHighly aggressive,invades adjucent structuresSonography: Diffusely hypoechoic with area of necrosis (78%) Dense amorphous calcifications (58%) Irregularities of the boundaries and the early
invasion of the thyroid capsule Infirtation if adjacent structures
Large anaplastic carcinoma with irregular margins, posterior extracapsular growth and infiltration of the laryngeal recurrent nerve(arrow)
Medullary carcinomaAccounts only 5% of all thyroid carcinomasMay be familial, assoc with MEN llA syndromeMulticentric and/or bilateralPrognosis worse than Follicular carcinomasSonography : >similar to papillary carcinoma>Hypoechogencity,iregular margins ,
microcalcifications(calcified amyloid deposits)>Hypervascularity with irregular blood vessels
A large hypoechoic nodule with thick halo and scatterd microcalcifications. Pathological diagnosis confirms Medullary carcinoma
Thyroid primary lymphoma 4% of all thyroid malignancies Rare,Mostly of Non-Hodgkin’s type Rapidly growing,may cause symptoms such as
dyspnea and dysphagia 70-80% cases arises from preexisting Chronic
thyroiditisSonography:
>Hypoechoic,lobulated,nearly avascular mass
>Cystic necrosis&encasement of great vessels of neck
>Adjacent thyroid parenchyma may heterogenous due chronic thyroiditis
Metastases Metastases to thyroid are infrequent Spread by hematogenous or lymphatic route Commonly from Melanoma(39%)breast(21%)
&RCC(10%) Solitary well cecumscribed nodules&diffuse involvement
Renal cell carcinoma metastases shows a round hypoechoic nodule (arrows) and an irregular-shaped hypoechoic nodule (arrowheads). (b) Color Doppler sonogram of the round nodule shows increased internal vascularity.
Feature BENIGN MALIGNANT
INTERNAL CONTENTS
Purely cystic High probability Rare
Cystic with thin septa High probability Rare
Comet tail artefact Intermediate probability Rare
ECHOGENICITY
Hyperechoic High Rare
Isoechoic Intermediate Low
Hypoechoic Intermediate Intermediate
HALO
Thin halo High Low
Thick incomplete halo Rare Intermediate
MARGIN
Well defined Intermediate Low
Poorly defined Low Intermediate
Rare :<1%Low :<15%Intermediate: 16 to 84 %High :>85%
CALCIFICATION
Egg shell calcification High probability Rare
Coarse calcification Intermediate Rare
Microcalification Low HIGH
DOPPLER
Preipheral flow pattern Intermediate Low
Internal flow pattern Low Intermediate
Grading of colour doppler flow mapping(Fukunari N, Nagahama M, Sugino K et al (2004) Clinical evaluation of color Doppler imaging for the differential diagnosis of thyroidfollicular lesions)
Grade1 nodules had no flow detectable. Grade 2 nodules had only peripheral flow,
without intranodular flow. Grade 3 nodules had low velocity central
flow.Grade 4 nodules had highintensity central
flow.
Grade 1 Doppler flow. Grade 1 lesions have no intranodular flow and no flow to the periphery
Grade 2 Doppler flow. Grade 2 lesions have peripheral flow only, without intranodular flow
Grade 3 Doppler flow. Great 3 lesions have low to moderate velocity central flow
Grade 4 Doppler flow. Grade 4 lesions have high-intensity central blood flow
Diffuse thyroid desease
Diagnosis usually made on the basis of clinical & lab findings
On occasion by FNA
Sonography is seldom indicated
DIFFUSE THYROID DESEASEAcute suppurative thyroiditisRare inflammatory desease(bacterial infection)Usually affects childrenSononography: useful to detect development of
the frank thyroid Abscessill defined,hypoechoic,heterogenous mass with
internal debris with or with out septa & gasAdjacent inflamatory nodes are often present
Sub acute granulomatous thyroiditis (De-Qearvain’s)Spontaneous remitting inflamatory desease
probably caused by Viral infectionClinical findings : fever,enlargement of gland and
painful on palpation
Sonography: May enlarged and hypoechoic with normal or
decreased vascularityDiffuse edema may present
This patient had a painful upper right lobe with elevated sedimentation rate typical of deQuervain’s thyroiditis.Note the line of demarcation (arrow) between the inflamed upper lobe and normal appearing lower lobe
Chronic autoimmune lymphocytic thyroiditis(Hashimoto’s thyroiditis
Occures usually in yong or middle aged womanPainless,diffuse enlargemant of thyroid gland
Sonography: >Diffuse coarse echopattern
>Hypoechoic Micronodules (+ve predictive value 90%)
>Fibrotic septations with pseudolobulated appearance
>Doppler imaging: “Thyroid inferno”
Hashimoto’s lymphocytic thyroiditis. The echo pattern is heterogeneous, hypoechoic micro nodules with interspersed discrete white lines representing fibrosis .
Also called “Swiss cheese” appearence
Hashimoto’s thyroiditis (hashitoxicosis) has intenseblood flow (thyroid inferno)
Grave’s deseaseCommon diffuse abnormality
Biochemically charecterised by hyperfunction
Diffusely hypoechoic in young patients (due to extensive lymphocytic infiltration)
Color doppler shows ‘Thyroid inferno”
Graves’ disease has been described as the“thyroid inferno,” typically showing very intense blood flow
Riedel’s strumaRarest type of inflammatory thyroid deseaseAlso called Invasive fibrous thyroiditisPrimarily affects women and tends to complete
destruction of the glandMay assoc with mediastinal or retroperitoneal
fibrosis or sclerosing cholangitisDiffusely enlarged & inhomogenous echopatternThe primary reason for sonography was to check for
extra thyroid extension with encasement of adjacent vessels
Para thyroid glands
Parathyroid glands These are two pairs(superior&inferior) Superior parathyroids develop from 4th pharyngeal poch Inferior parathyroids develop from 3rd pharyngeal pouch Measure 3-10 mm x 2-6 mm x 1-4 mm Lie between posteromedial thyroid lobes and carotid sheath
Close proximity to: a. Tracheoesophageal groove
b. longus colli muscles
Supplied by inferior thyroidartery & from anastamosis of sup&inf thyroid arteries
TECHNIQUE OF PARATHYROID ULTRASOUNDThe patient should be made to lie flat on a firm table
with one or two pillows placed under the shoulders to enable full extension of the neck
The structures of the neck should be carefully studied in two or more axis at multiple levels of the neck
Most common cause of primary hyperparathyroidism
>Adenoma,Hyperplasia,and carcinomaSecondary hyperparathyroidism usually a response
to chronic hypocalcemia in uraemic patients
Superior parathyroid adenoma seen in longitudinal view
Inferior parathyroid adenoma seen in longitudinal view.
Parathyroid adenoma indenting the posterior capsule of the thyroid gland.
Double inferior parathyroid adenoma in panoramic view
False positive Para thyroid adenoma:
Cervical lymph node
Prominent blood vessel
Esophagus
Longus colli muscle
Thyroid nodule False negative:
Miniamally enlarged adenomas
Multinodular thyroid goiters
Some ectopic adenomas
Parathyroid hyperplasia
Large hypoechoic parathyroid hyperplasia
on right side & small lesion on left side
capsulated parathyroid hyperplasias
> Para thyroid carcinoma with mild hypoechogenicity &irregular margins
NECK LYMPH NODES Neck lymph nodes are classified into:
> Submental,Submandibular,Parotid,facial,Deep
Cervical,Spinal accessory,Transverse cervical, retropharyngeal,occipital and matoid
Topographic classification based on 7 “levels”
> Level I incudes submental&submandibular
>Level II,III,IV deeep cervical ,nodes deep to SCM muscle and upper spinal accessory chain
>Level v Transverse cervical chain
>Level VI Anterior cervical chain
>Level VII Nodes in superior mediastinum
Once LN detected define whether benign or malignantSize,echogenic hilum,level of echogenicity,necrosis,
extracapsular spread,vascularity and calclfications should be evaluated
In inflammatory conditions: Diffuse,homogenous and preserve their normal oval shape
In malignancy: greater transverse diameter,rounded, asymmetric morphology, thin echogenic hilum
Cystic necrosis seen in TB nodes
Doppler: Benign LN shows Hilar flow¢ral vacular pattern
Malignant LN shows Aberrant vessels with course entering from the nodal capsule
Malignant LN have higher PI&RI than benign LN
Hyperplastic lymphnode of neck with elongated shape,cenral hilum
Central hilar blood suply
Typical metastatic adenopathy :rounded,isoechoic,with both perilesional&intralesional vascularity
Rounded hypoechoic TB node with macrocalcification and poor vascular supply