by Dr . Ahmed Refaey
Anatomy of thyroid gland
What are the indications for
thyroid ultrasound?
 Diffuse
enlargement on physical
 A palpable mass
 A non palpable mass seen on other
imaging( CT-MRI- nuclear scan)
 Abnormal thyroid function tests
Thyroid diseases
 Grave's disease
 Hashimoto thyroiditis
 De Quervain's
 Solitary
 multinodular
Solitary thyroid nodule
 Benign
 malignant
General features of the
solitary nodule
 Solid
/ cystic
 Comet tail sign
 Margins
 Calcification
 Color flow imaging
Nodules with large cystic
components are usually
benign nodules that have
undergone cystic
degeneration or
hemorrhage , however
about 20-30% of
papillary carcinomas also
have a cystic component,
indicating that not all
cystic thyroid nodules are
Comet tail sign
One highly specific sign
of a benignity of a
thyroid nodule is the
presence of comet tail
sign, signifying a
benign colloid nodule.
This sign is never
encountered in a
malignant lesion
 Hyperechoic
nodule  malignant in 4%
 Isoechoic nodule
 malignant in 26%
 Hypoechoic nodule  malignant in 63%
Peripheral halo of
echogenecity is seen
around the nodule.
 a complete halo is 12
times more likely to
indicate benign lesion
 An incomplete halo is 4
times more likely
benign than malignant
 Peripheral
rim calcification and large areas
of coarse shadowing calcifications are
more frequently seen in benign nodules’
 Fine punctate calcifications due to calcified
psammoma bodies are more frequently
seen in malignant nodules
Color flow imaging
There are three general patterns of vascular
distribution of the thyroid nodule:
 Type 1 : complete absence of flow signal within
the nodule.
 Type 2 : exclusive perinodular arterial flow
“type 1 and 2” are more common with benign nodules
Type 3 : intranodular flow with or without
significant perinodular flow and this type is
generally associated with malignant nodules.
Although none of the ultrasound
features above is BY ITSELF
pathognomonic for malignancy,
BUT when it used IN
COMBINATION they are very
useful in differentiating malignant
from a benign nodule
What are the features of a
benign thyroid nodule?
1- completely or nearly completely cystic,
especially with echogenic foci with comet
tail artifact
2- echogenic or isoechoic to normal tissue
3- a complete halo
4- well described margin
5- rim or large coarse calcifications
6- hypovasculrity
What are the features of
malignant thyroid nodule?
irregular margin
marked hypoechogenecity
Examination of adjacent
(1)- CCA and
internal jugular
vein : the presence
of thrombus within
CCA or IJV in
association with a
thyroid nodule is a
clue to the malignant
nature of the nodule
– spread to adjacent structures;
extrathyroid spread including involvement
of esophagus, trachea, strap muscles,
recurrent laryngeal nerve is another clue
to the malignant nature of the nodule
 (2)
 (3) The
cervical lymphadenopathy
LNs commonly involved are the
pretracheal , paratracheal and nodes
along internal jugular vein.
ultrasound features:
– Solid nodules, frequently isoechoic
– well defined margins
– Cystic component in 60 %
– Heterogeneous internal echopattern with
multiple septa , solid and cystic portions.
– On color flow imaging the nodules either
show type 1 or type 2 pattern
 It
is generally believed that malignancy is
common in a solitary nodule and that
multinodularity is usually associated with
benign disease, HOWEVER 10 – 20 % of
papillary carcinoma may be multicentric
Grave's disease
Hashimoto thyroiditis
De Quervain’s disease
 Diffuse
enlarged gland
 Color Doppler study is pathognomonic for
the disease , revealing hypervascularity
which is called “thyroid inferno”.
 the peak systolic velocity is more than 100
cm/sec “normal up to 25 cm / sec”
Three stages:
– Acute: enlarged in size and increased
– Chronic: enlarged gland with multiple linear
bright echoes throughout the hypoechoic
parenchyma as well as multiple small
hypoechoic nodules.
– Atrophic; end stage : small atrophic gland.
avascular with heterogenous echoes.
 The
inflammation does not involve the
entire gland but infiltrates the gland in a
non homogenous pattern.
 The sonographic correlate is a disordered
pattern of hypoechoic and hypervascular
Evaluation of nodules
incidentally detected by U/S
 Nodules
under 1.5 cm are followed
up by u/s
 Nodules over 1.5 cm are further
evaluated by FNA