SONOGRAPH LESIONS THE TAMILNA In partial t M HIC EVALUATION OF THYR WITH FNAC CORRELATIO Dissertation Submitted to ADU Dr. M.G.R MEDICAL UNIVER l fulfilment of the requirements for the award of the degree of M.D RADIODIAGNOSIS Branch VIII APRIL 2017 ROID ON RSITY
122
Embed
Dissertation - repository-tnmgrmu.ac.inrepository-tnmgrmu.ac.in/4760/1/200824217anupriya.pdf · By USG normal anatomical and pathological features such as size, margin ... muscles
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
SONOGRAPHIC EVALUATION OF THYROID LESIONS WITH FNAC CORRELATION
THE TAMILNADU Dr. M.G.R MEDICAL UNIVERSITY
In partial fulfilment of the requirements forthe award of the degree of
M.D RADIODIAGNOSIS
SONOGRAPHIC EVALUATION OF THYROID LESIONS WITH FNAC CORRELATION
Dissertation
Submitted to
THE TAMILNADU Dr. M.G.R MEDICAL UNIVERSITY
In partial fulfilment of the requirements for the award of the degree of
M.D RADIODIAGNOSIS
Branch VIII
APRIL 2017
SONOGRAPHIC EVALUATION OF THYROID LESIONS WITH FNAC CORRELATION
THE TAMILNADU Dr. M.G.R MEDICAL UNIVERSITY
CERTIFICATE
This is to certify that this dissertation entitled “Sonographic
evaluation of thyroid lesion with FNAC correlation” is a bonafide record
of the work done by Dr. Anu Priya J.T under guidance and supervision in
the Department of Radiodiagnosis during the period of her postgraduate study
for M.D Radiodiagnosis [Branch-VIII] from 2014-2017.
Dr. S. Sathish Babu, MD [Co-guide] Associate Professor Department of Radiodiagnosis, Sree Mookambika Institute of Medical Sciences [SMIMS] Kulasekharam [K.K District] Tamil Nadu -629161
Dr. G. Vijayakumar, MD [Guide] Professor and HOD Department of Radiodiagnosis, Sree Mookambika Institute of Medical Sciences [SMIMS] Kulasekharam [K.K District] Tamil Nadu -629161
Dr. Rema V. Nair, M.D., D.G.O.,
Director Sree Mookambika Institute of Medical Sciences [SMIMS] Kulasekharam [K.K District] Tamil Nadu -629161
DECLARATION
In the following pages is presented a consolidated report of
“Sonographic evaluation of thyroid lesion with FNAC correlation” a
cross sectional study, on cases studied by me at Sree Mookambika Institute of
Medical Sciences, Kulasekharam from 2015-2016. This thesis is submitted to
the Dr. M.G.R. Medical University, Chennai in partial fulfilment of the rules
and regulations for the award of MD Degree examination in Radiodiagnosis.
Dr. Anu Priya J.T
Junior Resident Department of Radiodiagnosis, Sree Mookambika Institute of Medical Sciences, Kulasekharam, Kanyakumari District. Tamil Nadu 629161.
ACKNOWLEDGEMENT
I thank God almighty, for giving me the strength, confidence and
perseverance to complete the study.
I express my heartfelt gratitude to our Director Dr. Rema V. Nair and
our Chairman Dr. Velayudhan Nair for providing me the infrastructure and
for permitting me to carry out the study in this institution. They are the
founders and pillars of the various activities initiated in our institution.
I thank my HOD and Guide Dr. G. Vijayakumar, for the creative
suggestions, timely advice and constant encouragement. It has been a
tremendous and wonderful experience to work under his guidance.
I thank my Co-guide Dr S. Sathish Babu for his valuable help,
suggestions and supervision throughout the study. He lent his full support in
all times of difficulties. His encouragement from the inception of this research
to its culmination has been profound.
I humbly thank Dr. Saritha V, Dr. Reshmi C.P, Dr. Arun A and
Dr Vinod S whose support, guidance, help, critical views and comments kept
me in full swing throughout my study period. Their suggestions were very
valuable at each stage of my dissertation work. I am indebted to them for their
guidance and support throughout my post graduate days.
I thank Dr. Karthik R Nair, Dr. Ajit Deshmuk, and Dr. Aneesh M.M
for their guidance during my initial study period.
I thank Dr. Mahtab Yeganegi, my co-pg, for her valuable and timely
help to complete my study on time. I am grateful to my junior post graduates
Dr. Bhupinderjit Singh Soori, Dr. Sakshi Mittal, Dr. Shyam Sudharsan and
Dr. Sparsh Yadav for the various technical aspects of my study.
I also extend my sincere thanks to our senior technicians Mr. Kamal
Chandran and Mr. Nappagam and all the staff members of Radiology for their
support.
Lastly I would like to express my heartfelt deepest gratitude to my
family for their continuing love and encouragement. All these where possible
with their constant support and sacrifice.
Dr. Anu Priya J.T.
LIST OF CONTENTS
Sl. No. Contents Page No
1. Introduction 1
2. Aims and Objectives 3
3. Hypothesis and Scientific Justification 4
4. Review of Literature 5
5. Materials and Methods 34
6. Analysis and Interpretations 41
7. Discussion 67
8. Conclusion 71
9. Summary 74
10. Bibliography
11. Appendices
LIST OF TABLES
Sl. No Tables Page No
1 Statistical parameters 40
2 Family history of thyroid disorder 42
3 Thyroid function test 42
4 Thyroid swelling 43
5 Size of thyroid gland 43
6 Echo texture of thyroid parenchyma 43
7 Vascularity of thyroid parenchyma 44
8 Nodules on thyroid parenchyma 44
9 Number of nodules 44
10 Size of thyroid lesions 45
11 Shape of thyroid lesions 45
12 Margins of thyroid lesions 45
13 Echogenecity of thyroid lesion 46
14 Halo in thyroid lesion 46
15 Contents of thyroid lesion 46
16 Calcification in the thyroid lesion 47
17 Vascularity of thyroid lesion 47
18 Ultrasound diagnosis of thyroid lesions 48
19 FNAC diagnosis of thyroid lesions 48
20 Matching of ultrasound and FNAC diagnosis 49
21 Comparison of ultrasound diagnosis with FNAC diagnosis 49
22 FNAC with size of nodule 50
23 FNAC with margins 51
24 FNAC with echogenicity 52
25 FNAC with halo 53
26 FNAC with contents 54
27 FNAC with calcification 55
28 FNAC with vascularity of nodule 56
29 Thyroid disorder and age 57
LIST OF FIGURES
Sl. No Figures Page No
1 Thyroid gland and its relation 6
2 Blood supply of thyroid 7
3 Thyroid hormones 10
4 Ultrasound of neck for thyroid 15
5 Normal thyroid ultrasound image 16
6 Position of needle 38
7 Ultrasound image of tip of needle within lesion 38
8 Gender distribution 41
9 Age distribution 42
10 FNAC with size of nodule 50
11 FNAC with margins 51
12 FNAC with echogenicity 52
13 FNAC with halo 53
14 FNAC with content 54
15 FNAC with calcification 55
16 FNAC with vascularity of nodule 56
Introduction
Introduction
Page 1
INTRODUCTION
The thyroid gland is an endocrine gland. It is a large gland and is the
only gland which is amenable to direct clinical examination. It is located
superficially. The superficial location of the thyroid gland helps in excellent
visualization. Superficial location also helps in the evaluation of its normal
anatomy, normal anatomical variants and pathological conditions by high
resolution real-time grey-scale sonography.1
The location of the thyroid gland makes high-resolution real time grey-
scale and color Doppler sonography. By USG, normal thyroid anatomy and
pathologic conditions can be demonstrated with remarkable clarity. The
thyroid gland has multiple critical functions such as regulating metabolic
functions of the body like cardiac output, skeletal growth and thermogenesis.
High resolution sonography is the best imaging modality for thyroid gland.
By USG normal anatomical and pathological features such as size, margin
number of nodules etc can be demonstrated2.
Thyroid gland is primarily evaluated clinically by palpation, and
determination of the levels of thyroid hormones. Surgical intervention may be
indicated when there is presence of a hypofunctional, or so-called “cold”
nodule, when malignant cells are detected by FNAC or when there is a large
thyroid lesion that cause symptoms such as dysphagia or hoarseness of voice.3
Introduction
Page 2
On USG thyroid, the nodules are evaluated. The size of nodule,
location of nodule in the thyroid gland, echotexture of the nodule, margins of
the nodule, presence of halo around the nodule, calcification within the
nodule, vascularity of the nodule, accessory nodules and associated cervical
nodes and contents of the nodule (solid, cystic or mixed) are characterized in
order to differentiate from benign and malignant nodule.4
Diffuse enlargement of the thyroid gland, thyroid nodules, thyroid
mass are seen sonographically and it may be palpable lesion or non palpable
lesion. The lesions may be symptomatic or asymptomatic. Multinodular goiter
was the commonest pathology and was seen in 40% of the cases. The females
were most commonly affected by multinodular goiter and constituted 90% of
goiter cases. Similarly colloid cyst was more common in females and they
constituted 20% of colloid cyst cases. Females also constituted 87% cases of
diffuse thyroid hyperplasia. By high frequency ultrasonography even the
smaller lesions which are not palpable can be identified. Certain ultrasound
characteristics of nodules (e.g., hypoechogenicity, microcalcifications, and
blurred & nodular margins) are associated with malignancy. Thyroid diseases
are predominant in females than males.2
Aims & Aims & Objectives
bjectives
Aims & Objectives
Page 3
AIMS AND OBJECTIVES
1. To study the ultrasonographic features of various thyroid lesions in
patients with thyroid disorders.
2. Correlate the sonographic findings with FNAC in the diagnosis of
thyroid lesions.
Hypothesis &
Justification
Hypothesis & Scientific Justification
Page 4
HYPOTHESIS AND SCIENTIFIC JUSTIFICATION
HYPOTHESIS
Null hypothesis states that sonography has specificity and sensitivity
similar to FNAC, in the detection of thyroid lesions.
SCIENTIFIC JUSTIFICATION
Thyroid disorders are endemic all over the world and in India also.
Sonographic evaluation is non invasive and it can be done on all age. By
using colour flow and Doppler the vascularity of the gland can be
demonstrated which is important in identifying the type of lesion. Thyroid
nodules are very common in the general population, but malignancy is
relatively rare.1 The goal of the ultrasound guided FNAC evaluation of non
palpable thyroid nodules is the early detection of malignant lesions and to
save the overt spread of malignancies, while identifying and avoiding
unnecessary surgery in those with benign, asymptomatic thyroid nodules.
This can be correlated with FNAC to confirm the type of lesion. UGS is very
helpful in locating the non-palpable thyroid nodules for FNAC and increases
the quality of diagnosis which is helpful for the clinical management of such
patients. USG can differentiate solid from cystic lesions solitary nodule
multinodular and diffuse enlargement and also extra thyroidal lesions.4
Review of Literature
Review of Literature
Page 5
REVIEW OF LITERATURE
Development:
The thyroid gland is develops from the median diverticulum. The
median diverticulum is seen around fourth week. It grows in downward and
backward direction. It is seen as a tubular structure, which bifurcates and
subsequently subdivides into a series of cellular cord like structures. From this
cord like structures isthmus and right and left lobes of the thyroid gland
develops. This connection when it is present between diverticulum and the
pharynx, it is called the thyroglossal duct. The thyroglossal duct undergoes
degeneration, its upper end forms the foramen cecum of the tongue, and its
lower end forms the pyramidal lobe of the thyroid gland.10
Anatomy of thyroid:
Thyroid gland is the superficially situated endocrine gland. It has two
lobes and it is situated in the lower neck drapped around the trachea on either
side. Centrally there is a band of tissue which connects the two lobes of
thyroid called isthumus.
The relation of thyroid gland to adjacent structure is anteriorly strap
muscles (sternohyoid, sternothyroid and omohyoid). The longus colli muscle
is located posterior to thyroid gland and the trachea is medial to the thyroid
lobe. Lateral relation to the thyroid gland is the large sternocleiodomastoid
Review of Literature
Page 6
muscle on both sides, the carotid artery on both sides and the internal jugular
vein on both sides. Esophagus is located posteriorly on the side of left lobe11.
Thyroid Size: The normal measurement of thyroid lobes are 4–6 cm in
craniocaudal length and 1.3–1.8cm in the anterioposterior and transverse
dimension is 2.5 – 3 cm. The normal isthmus has an anterioposterior thickness
of up to 3 mm.11
Fig 1. Diagramatic representation of cross section of thyroid gland and its relation to other structures
Around 10% to 40% patients have a pyramidal thyroid lobe which is
arising superiorly from the isthmus and laying in front of the thyroid cartilage.
Usually seen in young patients and atrophies in adulthood and becomes
invisible. 12
Fig 2. Diagramatic
Blood supply:
Upper pole of thyroid is supplied by 1
which is the superior thyroid artery and its accompanying vein, this vein
drains into the internal jugular vein
thyrocervical trunk and
gland is supplied by several branches which arise from inferior thyroid artery.
Inferior thyroid vein drains the lower border of gland. Middle
drains the middle thyroid gland
the carotid artery and enter the internal jugular vein.
is small and runs from brachiocephalic trunk in front of trachea
Review of
Fig 2. Diagramatic representation of blood supply of thyroid gland
Upper pole of thyroid is supplied by 1st branch of the external carotid
which is the superior thyroid artery and its accompanying vein, this vein
drains into the internal jugular vein.12 The inferior thyroid artery arises from
and passes behind the carotid sheath. Deep surface of the
supplied by several branches which arise from inferior thyroid artery.
Inferior thyroid vein drains the lower border of gland. Middle thyroid vein
drains the middle thyroid gland and courses laterally to pass in front or behind
the carotid artery and enter the internal jugular vein. The thyroidea ima artery
uns from brachiocephalic trunk in front of trachea13.
Review of Literature
Page 7
representation of blood supply of thyroid gland
branch of the external carotid
which is the superior thyroid artery and its accompanying vein, this vein
inferior thyroid artery arises from
Deep surface of the
supplied by several branches which arise from inferior thyroid artery.
thyroid vein
and courses laterally to pass in front or behind
The thyroidea ima artery
Review of Literature
Page 8
Lymphatics:
Major: Middle and Lower jugular, posterior triangle nodes.
Lesser: Pretracheal and para tracheal, Superior mediastinal nodes. The
lymphatic vessels end in the thoracic and right lymphatic trunk13
Nerve supply:
Superior cervical sympathetic ganglia, middle cervical sympathetic
ganglia and inferior cervical sympathetic ganglia.
The important structures that are important to note for surgery of
thyroid gland are the recurrent laryngeal nerves, the external laryngeal nerves
and the parathyroid glands14
Measurement of thyroid gland:
Thyroid gland measurement is important. It is done by taking three
measurements: They are the width, depth and length. Width of the thyroid
gland is measured by drawing an imaginary vertical line along the edge of
trachea laterally on the thyroid gland.
Depth is obtained by measuring the maximum anterior posterior
diameter in the same screen. Length of the thyroid gland is measured from the
cranial to caudal part of the lobe.15
Congenital anomalies of thyroid gland:
Hemiagenesis:
Thyroid gland is formed partially and this condition is called
hemiagenesis. It is a common anomaly. It can be diagnosed by USG.
Review of Literature
Page 9
Aberrant thyroid:
Aberrant thyroid is another anomaly of thyroid gland, which can occur
in neck along the track of formation of thyroid gland. From the base of tongue
thyroid gland develops and descends to the larynx. Then it divides into two
and forms two lobes and isthumus of thyroid gland. Sometimes this descent is
failing to occur or interrupted, leads to failed bifurcation.
On USG lateral aberrant thyroid may show a pedicle or some kind of
attachment to thyroid. A fine-needle aspiration may be necessary to rule out a
metastatic lymph node from a nonvisualized microcarcinoma of the thyroid.
Thyroglossal duct:
When the thyroid gland is developing, thyroid gland descends from
base of the tongue to the larynx, a duct is formed. Rarely this duct may persist
and it is called as thyroglossal duct. The duct which is near isthumus persist
as pyramidal lobe.
Thyroglossal duct cyst:
Sometimes 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. Brachial cleft cysts may look similar but its location is
more lateral in the neck.15,16
Review of Literature
Page 10
Fig 3. Thyroid Hormones
REGULATION OF THYROID HORMONES 14,18
Secretion of the thyroid hormone depends upon two major factors.
� HPT axis ( hypothalamus-pitutary-thyroid )
� Negative feedback mechanism.
HPT axis:
Thyrotropin releasing hormone (TRH) is secreated from the median
eminence of hypothalamus. It is a bipeptide molecule of weight 28,000
daltons. This TRH stimulating the thyrotropes of anterior pituitary to secrete
and release TSH. TSH stimulates the follicular cells of thyroid gland and
stimulates every step of thyroid hormone synthesis.
Review of Literature
Page 11
The ability of TSH to trap iodine depends to some extent, on the blood
iodine concentration. If the concentration of blood iodine high in high iodine
intake, the presence of adequate TSH, iodine trapping by follicular cells is
poor. If the food iodine intake is very low, TSH causes iodine trapping.
Negative feedback mechanism:
If food iodine content is very low, a little or no T4 is found. By the
negative feedback mechanism, TSH secretion increases leading to goiter and
this condition is called as iodine deficiency goiter. In case of hypothyroidism,
the serum concentration of TSH increases. In hyperthyroidism, the TSH
concentration of serum should be very low or nil.
Effects of TSH19, 20, 21:
� Increases proteolysis of thyroglobulin.
� Increases activity of iodine pump.
� Increases iodination of tyrosine.
� Increases size, number and secretory activity of the thyroid cells.
a) Effect of thyroid hormone on growth:
Thyroid hormone is necessary for growth & maturation. For this, the
action of T4 & T3 is helped by Insulin like growth factor & growth hormone,
T3 & T4 are required even in fetal life for maturation of growth centres.
Thyroid hormones also stimulates the process of bone remodelling. Thyroid
hormone are required for normal functioning of skeletal muscles18.
Review of Literature
Page 12
b)Effect of thyroid hormone on CNS:
Presence of T3 & T4 is essential in the fetal brain during infancy for
proper development of brain, T3 & T4 are required for growth of cerebrum,
cerebellum, proliferation and branching of nerve fibers, along with
myelination.
The nerve fiber branching requires the presence of NGF (nerve growth
factor). If thyroid deficiency is not corrected within few months of birth, it
leads to cretinism.18 The hyperthyroid individual is likely to have extreme
nervousness and many psychoneurotic tendencies, such as anxiety
complexes, extreme worry and paranoia.14
c) Stimulation of fat metabolism
Thyroid hormone mobilizes lipid from fat tissue. This decreases the fat
stores in the body. This also increases the free fatty acid concentration in the
plasma and greatly accelerates the oxidation of free fatty acids by the cells.14
d) Stimulation of carbohydrate metabolism
Thyroid hormones stimulate all aspects of carbohydrate metabolism,
including uptake of glucose by the cells, enhanced glycolysis, enhanced
gluconeogenesis, increased rate of absorption from GIT, and even increased
insulin secretion and its resultant effect on carbohydrate metabolism. All this
effect probably results from the overall increase in the cellular metabolic
enzymes caused by thyroid hormone.14
Review of Literature
Page 13
e) Effect on plasma and liver:
Increase in thyroid hormone decreases the concentration of cholesterol,
phospholipids and triglycerides in the plasma. It increases the free fatty acids
and vice versa. The large increase in circulating plasma cholesterol in
prolonged hypothyroidism is associated with atherosclerosis.14
f) Effect on basal metabolic rate:
Thyroid hormone increases the metabolism in almost all the cells of
the body. Therefore excessive quantities of hormone can occasionally
increase the BMR from 60% to 100% above normal. Conversely, when no
thyroid hormone is produced, BMR falls almost to one half of normal.18,19
g) Effect on Cardiovascular system.19
• Increases blood flow and cardiac output
• Increases heart rate
• Increases heart strength
• Normal arterial pressure.
h) Effect on sympathetic system:
Thyroid hormones facilitate all the three actions of catecholamines which
include glycogenolysis, adipose tissue lipolysis and neoglucogenesis. Thyroid
hormones increase the β1 adrenergic receptors of heart, hence in thyrotoxicosis
catecholamine response to heart (eg:tachycardia, palpitation) is enhanced,
therefore in thyrotoxicosis along with anti-thyroid drugs β-blockers are used.14,19
Review of Literature
Page 14
i) Effect on the function of the muscles:
Increase in thyroid hormone usually makes the muscle react with
vigor, but with excessive hormone production, the muscles become
weakened because of excessive protein catabolism. Conversely lack of
thyroid hormone causes the muscles to become sluggish, they relax slowly
after a contraction.19
j) Effect on Gastrointestinal motility:
Hyperthyroidism often results in diarrhoea and hypothyroidism often
results in constipation.19
k) Effect on menstrual and reproductive function:
Lack of the thyroid hormone causes menorrhagia, polymenorrhoea,
irregular menses, amenorrhoea. They are also required for follicular
development, ovulation as well as for proper progress of pregnancy.14,19
l) Effect on sleep:
Due to the exhausting effects of thyroid hormone on the musculature
and on CNS, the hyperthyroid subject often has a feeling of constant
tiredness. But because of the excitable effect of thyroid hormones on the
synapses, it is difficult to sleep. Conversely extreme somnolence is a
characteristic of hypothyroidism, with sleep sometimes lasting from 12 to 14
hours a day.
Review of Literature
Page 15
Iodine is an essential micronutrient for the synthesis of thyroid
hormones. T4 and T3 contains 4 and 3 atoms of iodine respectively. Iodine
is essential in minute amounts for normal growth and development of
humans22.
Imaging modalities of thyroid:
Ultrasound examination:
High frequency (7-15 MHz) linear-array transducer is used. Since
thyroid is located superficial sonography is the best imaging modality for
evaluation of thyroid. Scanning is done both in transverse and longitudinal
planes. Real time imaging of thyroid gland is done, it is performed using both
gray-scale and color Doppler techniques.
Fig 4. Picture shows the position of probe over the neck for ultrasound imaging
Review of Literature
Page 16
Fig 5. This image shows the normal thyroid gland on ultrasound examination
Advanced ultrasound techniques:
Ultrasound elastography is a newer technique. It is a dynamic
technique which estimates stiffness of tissues by measuring the degree of
distortion under external pressure. It is used to study the elasticity/ hardness
of a thyroid nodule by which it can be differentiated as benign and malignant.
On compression benign nodules are softer and gets deformed easily whereas
malignant nodules are less deformed on compression. The elastographic
image (elastogram) is displayed in the B-mode image as a color scale. Based
on the local tissue elasticity it is seen as (i) very soft - blue color (tissue with
greatest elastic strain) (ii) very hard - red color ( tissue with no strain).
Another latest technique is real-time shear elastography which
characterizes and quantifies tissue stiffness. It is better than conventional
elastography. The disadvantage of elastography is, it cannot assess the
nodules which are not surrounded by thyroid tissues.
Review of Literature
Page 17
Contrast-enhanced ultrasound (CE-US) is another newer technique. It
helps in characterizing a thyroid nodule as benign or malignant. For this
technique ultrasound specific contrast (e.g. Sono Vue) is used. Ultrasound
specific contrast with pulse inversion harmonic imaging improves the efficacy
of ultrasound in diagnosing malignant thyroid nodule. Depending on the
enhancement patterns the nodules can be differentiated as benign and
malignant lesions. Benign lesion shows ring enhancement, whereas
heterogeneous enhancement is seen in malignant lesions.23
Computed Tomography:
CT imaging involves multidetector acquisition from the base of the skull
to the bifurcation of trachea with or without contrast. Multiplanar 2-mm
axial, coronal and sagittal images are obtained. CT imaging is more useful in
malignant condition for characterizing the lesion and seeing the extent, to
evaluate the cervical lymphnodes and characterize the nodes. Relationship of
thyroid nodule to adjacent structures can also be evaluated. Lateral neck
nodal disease sometimes not well investigated by US, as well as nodal
disease in the parapharyngeal, retrolaryngeal, retrotracheal and retrosternal
regions, are clearly and reliably seen on contrast CT. Combination of US and
contrast CT produces an effective preoperative nodal map24.
Magnetic Resonance Imaging
Magnetic resonance imaging is used in some conditions. A neck
receiver coil is used to provide optimal image with optimal spatial resolution
Review of Literature
Page 18
and signal to noise ratio. The images are taken in all three planes, axial,
coronal and sagittal. Slices are taken with thickness of around 3 to 5mm. T1
weighted, T2 weighted images are taken. Presaturation pulse sequence is
taken to reduce the flow artefact. The major indication of MRI imaging is to
evaluate the retrosternal extension of thyroid, invasion in cases of
malignancy. But MRI does not provide information about specific nodules.25
Scintigraphy:
Scintigraphy is done to assess thyroid nodules. It is used in patients with
suppressed TSH level in whom scintigraphy allows assessment of the functional
activity of a thyroid nodule and activity of the whole gland. A functioning, or
“hot,” thyroid nodule is not malignant mostly, only few cases were reported as
malignancy. Although a nonfunctioning, or “cold,” nodule at scintigraphy is
commonly thought to indicate an increased risk of thyroid malignancy, as many
as 77% of cold thyroid nodules may be benign. Thyroid scintigraphy therefore is
not so helpful for differentiating a benign nodule from a malignant nodule.11
Benign lesions11
(i) Thyroiditis
• Chronic lymphocytic (Hashimoto) thyroiditis
(ii) Benign follicular nodule
• Adenomatoid nodule.
• Colloid nodule
Review of Literature
Page 19
(iii) Follicular adenoma
• Hurthle cell adenoma
Malignant lesions
(i) Papillary carcinoma
(ii) Follicular carcinoma
• Hürthle cell carcinoma
• Poorly differentiated carcinoma
(iii) Anaplastic/undifferentiated carcinoma
(iv) Medullary carcinoma
(v) Lymphoma
(vi) Metastasis
Benign lesion:
The sonographic characteristic of benign nodules are ovoid or flat
shape, smooth margin, isoechogenicity and peripheral vascularity. Peripheral
vascularity on sonography is defined as vascular predominance in the
periphery of the nodule in a color Doppler.26
Thyroiditis:
Lymphocytic thyroiditis is also known as hashimotos thyroiditis. It can
be diffuse or focal nodule. Diffuse is seen as heterogenous hypoechogenicity
with micronodulations. Focal thyroid nodule is seen as solid, ill defined
hypoechoic nodule. Lymphocytic thyroiditis has predisposition to develop as
Review of Literature
Page 20
papillary thyroid carcinoma. Sonographic features evaluated in the lesion are
internal component, margin, echogenicity , shape and calcifications. An
internal components were classified based on four categories: 1) solid mass,
2) mass that has a solid portion of more than 50%, 3) mass that has a solid
portion of less than 50%, and 4) cyst. Sonographic features suspicious of
malignancy were defined as marked hypoechogenicity (decreased echogenicity
on comparing with the surrounding strap muscle), microlobulated or irregular
margin, microcalcification, hyperechoic foci, either with or without acoustic
shadows), or nonparallel shape (anteroposterior diameter greater than the
transverse diameter). As disease progresses micronodules can increase in size
and it can be seen as large hypoechoic mass on sonography.
Focal nodules which was proved to be thyroiditis was seen as
hypoechoic nodules with ill defined margins, so it is difficult to differentiate
from papillary thyroid carcinoma and lymphoma. On cytology the lesion is
diagnosed as lymphocytic thyroiditis when it shows grouped, monolayer sheets
or scattered follicular and Hurthle cells and scattered lymphocytes; scanty
colloid; follicular cells showed nuclear atypia with nuclear enlargement.13
Benign Follicular Nodule
Nodular goiter, colloid nodules, adenomatoid or hyperplastic nodules,
nodules in Graves disease, and macrofollicular subtype follicular adenoma
are the different types of benign follicular nodule.
Review of Literature
Page 21
It is caused due to hyperplasia of the gland. Etiology are iodine
deficiency (endemic), disorders of hormonogenesis (hereditary familial
forms), and poor utilization of iodine. More common in females than males in
the age group 35 to 50. There is increase in the size of the gland. Hyperplastic
nodules undergo liquefactive degeneration and there is accumulation of blood,
serous fluid, and colloid substance.27
Sonographically the hyperplastic nodules are isoechoic to normal
thyroid tissue but can become hyperechoic because of the interfaces between
cells and colloid substance. Rarely seen as hypoechoic sponge like or
honeycomb pattern. A thin peripheral hypoechoic halo is seen around the
nodule , which is caused by the blood vessels and compression of adjacent
normal parenchyma. Echogenic foci with comet-tail artifacts which are
caused by microcrystals or aggregates of the colloid substance. These colloid
substances move like snowflakes, within the fluid collection28.
Follicular adenoma:
It is a benign neoplastic growth contained within a capsule. Adenoma
implies specific benign new tissue growth with gland like cellular structure.
More frequent in females. Causes can be thyroid radiation, chronic TSH
stimulation etc. The benign follicular adenoma is a true neoplasm of thyroid
which is characterized by compression of adjacent tissues and fibrous
encapsulation. Based on the type of cell proliferation it is classified into
subtypes as the fetal adenoma, Hurthle cell adenoma, and embryonal
Review of Literature
Page 22
adenoma. Most are solitary but sometimes it can be multiple also.
Sonographically adenomas are seen as hyperechoic, isoechoic or hypoechoic
solid masses with a peripheral hypoechoic halo that is smooth and thick.
Mostly the halo is complete and it is due to the fibrous capsule and blood
vessels, which is seen by color Doppler. Vessels are seen passing from the
periphery to the central regions of the nodule, which is seen as a "spoke-and-
wheel-like" appearance. Follicular carcinoma and follicular adenoma cannot
be differentiated by ultrasound or by cytological evaluation.29,30
Malignant lesions:
US features, such as marked hypoechogenicity, irregular margin,
microcalcifications, and a taller-than-wide shape have been introduced as
potential predictors for the presence of thyroid malignancies.26
Papillary carcinoma:
Females are more affected than males and the peak age group is 3rd
decade and 7th decade. Spread is through lymphatics and mostly seen in
adjacent cervical lymphnode.
Sonographic features are
a. Hypoechogenicity (seen in 90% of cases), which is due to closely
packed cell content, and minimal colloid substance.
b. Microcalcifications, seen as tiny, punctuate hyperechoic foci, with or
without acoustic shadowing microcalcifications may be the only
Review of Literature
Page 23
sonographic sign of aggressive cases of papillary carcinomas of
childhood which is rare, even without the evidence of a nodular lesion.
c. Hypervascularity (seen in 90% of cases), with disorganized
vascularity, is mostly seen.
d. Cervical lymph node metastases is seen, which contains tiny, punctate
echogenic foci which is caused by microcalcifications. Retraction of
capsule can be seen. Papillary carcinomas rarely show cystic changes31.
Follicular Carcinoma:
More common in females than males and accounts for 5% to 15% of
thyroid cancer. It can be minimally invasive and widely invasive follicular
carcinoma. Minimally invasive follicular carcinoma is encapsulated and there
is focal invasion of capsular blood vessels of the fibrous capsule
histologically. Widely invasive follicular carcinoma is not well encapsulated,
and the invasion of vessels and adjacent thyroid is seen. Both the variants of
follicular carcinoma spreads hematogenously and distant metastasis is more
common. Brain, lung, liver and bone are more prone to metastases than
cervical lymph node. Sonographic features of follicular carcinoma are
irregular tumor margins, a halo which is thick and irregular .On color Doppler
imaging internal blood vessels shows tortuous or chaotic arrangement.32,43
Medullary Carcinoma:
Medullary carcinoma arises from parafollicular C cells of thyroid gland
which is derived from the neural crest. So it is a neuroendocrine tumor and is
Review of Literature
Page 24
classified as part of apudomas. More common in females than males and peaks
age group is 40 to 65 years. Associated with MEN 2 syndromes. Sonographic
features are hypoechogenicity, internal vascularity, spiculated margins, and
calcifications. Longitudinal diameter of nodules are greater than transverse
diameter. These nodules are larger and more cystic and shows homogenous
echotexture in the solid component of the lesion. These lesions outgrow their
blood supply and this leads to necrosis and cystic degeneration. Nodal
metastasis is seen in nodes with irregular margins or bulging outlines,
heterogeneous echotexture, calcifications (micro or macrocalcifications), cystic
foci, and abnormal vascularity. Distant metastases is also seen and the common
distant metastatic sites are the liver, lung and mediastinum and bone.33
Lymphoma:
PTL is a rare pathology and constitutes about 5% of all thyroid
malignancies. It is more common in females than males; most patients are
diagnosed in their 6th or 7th decade of life. Based on the sonography lymphoma
is classified as nodular, diffuse, and mixed types. Posterior acoustic enhancement
is useful in discriminating PTL from severe Hashimoto’s thyroiditis. Rapid
growth , painless thyroid enlargement, and pressure symptoms are the common
clinical presentations of Lymphoma. Multifocal, markedly hypoechoic, goiter,
hypervascular and absence of calcification, were features of non-diffuse type of
lymphoma. Due to the extremely low level of internal echoes, nodular PTLs
have been described as ‘‘pseudocysts’’ in previous studies. 34
Review of Literature
Page 25
Metastasis
Metastatic disease is suspected when a solid thyroid nodule is found in
patient with a known nonthyroid malignancy.
Description of thyroid nodule:
Benign and malignant thyroid nodules have different features which
helps in differentiating the lesion as benign or malignant. The features are as
follows.
Benign lesion
US features suggestive of a benign nodule are an ovoid-to-round
shape, a well-defined smooth margin, isoechogenicity, and a spongiform
appearance. Calcifications can be there. Rim calcification without cortical
break43.
Malignant characteristic of thyroid nodule:
High-resolution ultrasonography is commonly used to evaluate the
thyroid gland. Microcalcifications are one of the most specific US findings of
a thyroid malignancy. Other US features are marked hypoechogenicity,
irregular margins, and the absence of a hypoechoic halo around the nodule.
Lymphadenopathy and local invasion of adjacent structures are specific
features of thyroid malignancy. Thyroid malignancies are relatively rare.
Multiple features of thyroid malignancy if appears in combination it is
possible to make an accurate prediction.35,43
Review of Literature
Page 26
Direct tumor invasion of adjacent soft tissue, extracapsular extension
and metastases to lymph nodes are highly specific for thyroid malignancy.
Pressure effects such as dysponea, hoarseness and dysphagia are caused by
invasion of the trachea or larynx, the recurrent laryngeal nerve, or the
esophagus35.
Calcification:
Microcalcification is commonly seen in papillary carcinoma. It has a
specificity of 85% to 95%. Coarse calcifications are more common in
medullary carcinoma it can be seen on papillary carcinoma. Inspissated
colloid calcifications may mimic microcalcification. It is distinguished by ring
down artifact/reverberation artifact/ comet tail artifact. Peripheral calcification
is more common in multinodular goiter. Break in peripheral calcification is
suggestive of malignant transformation of the underlying goiter28.
Margins, contour and shape:
Hypoechoic halo is suggestive of benignity. It is composed of
pseudocapsule of fiberous connective tissue or compressed thyroid
parenchyma. In some lesions the margin is not well defined. Ill defined
margins indicate infiltration to adjacent parenchyma. Shape is ovoid to round
is chareteristic of benign lesion and taller than wide is suggestive of malignant
lesion. Contour of the lesion is smooth and rounded in benign and irregular
jagged edges are seen in malignant lesions.36
Review of Literature
Page 27
Echogenicity:
Malignant lesions are markedly hypoechoic compared to the strap
muscles. Malignant nodules are hypoechoic with predominantly solid
components, some of the malignant lesion can have cystic content. Benign
lesions are hyperechoic or iso echoic commonly. Contents can be cystic or
solid37.
Vascularity:
Marked intrinsic hypervascularity is seen in malignant lesion in which
flow in the central part of lesion is more than the flow in the surrounding area.
Benign nodules can show perinodal vascularity or it can be avascular37.
Lymphnode metastasis.
US features that are suspicious about lymph node metastases are a
A. Cyto-histology and clinical correlation of thyroid gland lesions: A 3
year study in a tertiary hospital. Clin Cancer Investig J 2014;3:208-12
49. Yeh HC, Futterweit W, Gilbert P. Micronodulation: ultrasonographic
sign of Hashimoto thyroiditis. J Ultrasound Med 1996; 15:813-819
50. Brander AEE, Viikinkoski VP, Nickels JI, Kivisaari LM. Importance
of thyroid abnormalities detected at us screening: a 5-year follow-up.
Radiology 2000; 215:801-806.
51. do Rosario PWS, Fagundes Ta et al. USG features of papillary thyroid
carcinoma. J Ultra Med 2004;23:572-78.
Appendices
CONSENT FORM
PART 1 OF 2
INFORMATION FOR PARTICIPANTS OF THE STUDY
Dear Volunteers, We welcome you and thank you for your keen interest in participating in this research project. Before you participate in this study, it is important for you to understand why this research is being carried out. This form will provide you all the relevant details of this research. It will explain the nature, the purpose, the benefits, the risks, the discomfort, the precautions and the information about how this project will be carried out. It is important that you can read and understand the contents of the form carefully. This form may contain certain scientific terms and hence, if you have any doubts or if you want more information, you are to ask the study personnel or the contact person mentioned below before you give your consent and also at any time during the entire course of the project.
1. Name of the Principal Investigator : Dr.Anu Priya J T Postgraduate-M.D Radiodiagnosis
Sree Mookambika Institute of Medical Sciences,
Kulaseharam
2. Name of the Guide : Dr.VijayKumar.G Professor and HOD
Department of Radiodiagnosis Sree Mookambika Institute of Medical Sciences,
Kulasekharam
3. Name of the co-guide : Dr. Satish Babu Associate Professor
Department of Radiodiagnosis Sree Mookambika Institute of Medical Sciences Kulasekharam
4. Institute: details with Address : Sree Mookambika Institute of Medical Sciences,
Kulasekharam, Kanyakumari District-629161 Tamil Nadu
5. Title of the study: Sonographic Evaluation of Thyroid Lesions with FNAC Correlation.
6. Background Information: Thyroid disorders are endemic and they need evaluation for the further
management. Ultrasound is an important imaging modality to detect the lesions.1 Ultrasound is conducted to know the types of lesions and to know the nature and distribution of thyroid lesions. The ultrasound findings will be correlated with FNAC to know the sensitivity and specificity.4
7. Aims and Objectives: i. To study the ultrasonographic features of various thyroid lesions in
patients with thyroid disorders. ii. Correlate the sonographic findings with FNAC in the diagnosis of
thyroid lesions.
8. Scientific justification of the study: Thyroid disorders are endemic all over the world and in India also.
Sonographic evaluation is non invasive and it can be done on all age. By using colour flow and Doppler the vascularity of the gland can be demonstrated which is important in identifying the type of lesion. This can be correlated with FNAC to confirm the type of lesion. Thyroid nodules are very common in the general population, but malignancy is relatively rare lesions.
9. Procedure of the study: All patients with valid consent will undergo the following : 1. Ultrasound examination of the thyroid will be done 2. Utrasound guided fine needle aspiration will be done and the aspirated
material from the thyroid will be sent for pathological examination. After all the tests, the FNAC will be correlated for the study purposes.
10.Expected risk of the participants:
The risks of the procedure are minimal. One risk is minor bleeding which may occur in the lesion or under the skin and may result in swelling and bruise, mild discomfort and mild pain. T his generally is limited if firm pressure is applied to the aspirated site following removal of needle.
11. Expected benefits of the research for the participants: Detect any thyroid lesions.
12. Maintenance of confidentiality: All data collected for the study will be kept confidentially. No personal
details will be revealed.
13. Why have I been chosen to be in this study: Since clinical features suggestive of thyroid disease are present and future
investigations are necessary.
14. How many people will be in the study: 62
15. Agreement of compensation to the participants: No
16. Anticipated prorated payment, if any, to the participants of the study: Nil
17. Can I withdraw from study at any time during the study period: Yes
18. If there is any new finding/information, would I be informed: Yes
19. Expected duration of the participants participation in the study: Single visit.
20. Any other pertinent information: No
21. Whom do I contact for further information:
Place:
Date:
Signature of the Participant Signature of Principal Investigator
For any study related queries, you are free to contact Dr Anu Priya J T -Post Graduate Department of Radiodiagnosis
Sree Mookambika Institute of Medical Sciences, Kulasekharam629161
The details of the study have been explained to me in writing and details have been fully explained to me. I am aware that the results of the study may not be directly beneficial to me but will help in the advancement of medical sciences. I confirm that I have understood the study and had the opportunity to ask questions. I understand that my participation in the study is voluntary and that I am free to withdraw at any time, without giving any reasons, without the medical care that normally be provided by the hospital being affected. I agree not to restrict the use of any data or results that arise from this study provided such a use is only for scientific purpose(s). I have given details of the study. I fully consent to participate in the
study titled “Sonographic Evaluation of Thyroid Lesions with FNAC Correlation.”
Serial no/Reference no:
Name of the participant:
Address of the Participant:
Contact number of the Participant:
Signature/Thumb impression of the participant/Legal guardian
Witness
1.
2.
Date:
Place:
CASE RECORD FORM
1. Serial No.
2. Name
3. Age in years
4. Sex
5. Address and phone no.
6. Family history of thyroid disorder [01-No, 02- Yes] 7. Thyroid function test [01 –Normal, 02- Hypothyroidism, 03- Hyperthyroidism] 8. Clinical examination – thyroid swelling [01- No, 02- Yes] SONOGRAPHIC EVALUATION 9. Size of thyroid gland [01- Normal, 02- Enlarged] 10. Echo texture of thyroid parenchyma [01- Homogenous, 02-Heterogenous] 11.Vascularity of thyroid parenchyma [01- Normal, 02- Increased] 12. Nodule [01- Absent, 02- Present] 13. Description of Nodule i) No. of nodules [01- Single, 02- Multiple] ii) Size [01- <5mm, 02- 5mm to 1cm, 03- >1cm]
iii) Description of nodules >5mm a) Shape [01- Ovoid to round, 02-Taller and wide] b) Margins [01- Well defined smooth, 02- Well defined spiculated, 03- Ill defined] c) Echogenicity [01-Anechoic 02- Hypoechogenic, 03- Isoechogenic, 04- Hyperechogenic] d) Halo [01- Absent, 02- Complete, 03- Incomplete] e) Contents [01- Predominantly solid, 02- Predominantly Cystic, 03- Comet tail artifact] f) Calcification [01- Absent, 02- Rim Calcification, 03- Macrocalcification, 04- Microcalcification] g) Vascularity [01- Avascular, 02- Intrinsic hypervascular, 03- Perinodal Vascularity 04- both intrinsic and perinodal vascularity ]
14) Ultrasound diagnosis 15) FNAC report
LIST OF ABBREVATIONS USED
cm - centimeter
mm - millimeter
USG - ultrasonography
US - ultrasound
TSH - Thyroid stimulating hormone
T3 - Tri iodothyronine
T4 - Thyroxine
mHz - megahertz
CNS - Central Nervous System
Β - Beta
CT - Computed tomography
MRI - Magnetic Resonance Imaging
FNAC - Fine Needle Aspiration Cytology
PTL - Primary thyroid lymphoma
TIRADS - Thyroid Imaging Reporting and Data System
S- FNAC - Standard FNAC
USG- FNAC - Ultrasound guided FNAC
MNG - Multi Nodular Goitre
STN - Solitary nodule thyroid
S-FNAC - Standard FNAC
USG-FNAC - USG guided FNAC
TP - True positive
TN - True negative
FP - False positive
FN - False negative
CASE 1
Well defined spiculated hypoechoic nodule with few specks of microcalcification – s/o Papillary carcinoma
CASE 2
Well defined anechoic (cystic) nodule – s/o colloid goiter.
CASE 3
Well defined isoechoic nodule with increased perinodal vascularity.
Well defined hypoechoic lesion in the left lobe of thyroid gland was diagnosed as colloid goiter on USG. On FNAC this lesion was diagnosed as papillary
carcinoma.
CASE 6
Well defined smooth margin, hyperechoic, solitary nodule on the right lobe of thyroid – s/o adenomatous nodule.
CASE 7
Well defined cystic lesion with comet tail artifact – colloid goiter
CASE 8
Well defined lesion with speculated margins and macrocalcification noted in the left lobe of thyroid gland – medullary carcinoma.
CASE 9
Well defined smooth margin hypo echoic nodules – Multinodular goiture
CASE 10
Enlarged thyroid gland with heterogeneous echotexture and increased vascularity – s/o thyroiditis.
FNAC
Colloid nodule Colloid nodule
Hashimotos
Hashimotos
MNG
Papillary CA Thyroid
Papillary CA Thyroid
Papillary CA Thyroid
MASTER CHART
Sl. No AGE SEX FAMILY H/O TFT THYROID
SWELLING TSIZE OF THYROID
GLAND ECHOTEXTURE OF THYROID
PARENCHYMA
VASCULARITY OF THYROID
PARENCHYMA NODULE
NO.OF NODULE
SIZE
1 22 F 2 3 2 2 2 2 2 2 1
2 37 F 1 1 2 2 1 1 2 2 3
3 42 F 1 2 2 2 2 2 2 2 3
4 55 F 1 2 2 2 2 2 2 1 3
5 35 F 1 2 2 2 1 1 2 2 3
6 64 F 2 1 2 2 1 1 2 2 3
7 28 F 1 3 1 2 2 2 1
8 65 F 2 1 2 1 1 1 2 2 3
9 35 F 1 1 1 1 2 2 2 2 3
10 50 F 1 3 1 2 2 2 2 2 1
11 18 F 2 3 1 2 2 2 1
12 59 F 1 2 2 2 2 2 2 2 1
13 47 F 1 1 1 1 1 1 2 2 3
14 35 F 2 3 2 2 1 2 2 1 3
15 41 F 1 1 2 2 1 1 2 1 3
16 60 F 2 2 2 2 1 1 2 2 3
17 19 F 1 3 2 2 2 2 2 2 1
18 20 F 1 3 2 2 2 2 1
19 35 F 1 1 2 2 2 2 2 2 2
20 33 F 1 1 2 2 2 2 2 2 1
21 36 F 1 2 1 2 2 2 2 2 3
22 40 F 2 1 2 2 2 2 2 1 2
23 37 F 1 1 2 2 1 1 2 2 1
24 45 F 2 2 2 2 1 1 2 1 3
25 35 F 1 1 1 2 2 2 2 2 1
26 36 F 1 1 1 2 2 2 2 1 3
27 17 F 2 2 1 2 2 2 2 2 1
28 50 F 1 3 2 2 2 2 2 1 3
29 28 F 2 1 1 2 2 2 2 2 1
30 25 F 1 3 2 2 2 2 2 2 1
31 50 F 2 2 2 2 2 2 2 1 3
32 25 F 1 2 1 2 2 2 1
33 44 F 2 1 2 1 1 1 2 2 3
34 39 F 1 2 2 1 1 1 2 1 2
35 51 F 1 3 2 1 1 1 2 1 2
36 26 F 1 3 1 2 2 2 2 2 1
37 68 F 1 1 2 1 1 1 2 2 2
38 32 M 1 3 2 2 1 1 2 2 2
39 44 F 2 2 2 2 2 2 2 2 1
40 60 F 1 2 2 2 2 2 2 2 3
41 47 F 2 2 2 2 1 1 2 1 2
42 27 F 1 3 2 2 1 1 2 1 3
43 48 F 1 1 1 1 1 1 2 1 2
44 23 F 1 2 2 2 2 2 2 2 1
45 50 F 2 3 2 1 1 1 2 2 3
46 60 F 2 1 2 1 1 1 2 2 3
47 58 F 1 1 2 1 2 2 2 2 3
48 39 F 2 3 1 2 2 2 2 2 1
49 22 F 1 3 2 2 2 2 1
50 47 F 1 2 2 1 1 1 1 1 3
51 28 F 1 3 2 2 2 2 2 2 1
52 48 F 1 2 2 2 2 2 2 2 1
53 30 F 2 1 2 1 1 1 1 1 3
54 29 F 1 2 2 2 2 2 2 2 1
55 45 F 1 3 2 1 1 1 1 1 2
56 55 F 1 1 2 2 2 2 2 2 1
57 31 F 2 1 1 1 1 1 2 2 3
58 41 F 1 2 1 2 2 2 2 2 1
59 45 F 2 2 2 2 1 1 2 1 3
60 53 F 1 1 1 2 1 1 2 2 3
61 42 M 1 1 2 2 1 1 2 2 3
62 52 F 1 2 2 2 2 2 1
Sl. No SHAPE MARGINS ECHOGENICITY HALO CONTENTS CALCIFICATION VASCULARITY ULTRASOUND DIAGNOSIS FNAC REPORT