Imaging approach in thyroid nodules by Dr. Kamal Adhikari

1. IMAGING APPROACH IN
THYROID NODULES
Dr.Kamal Adhikari
MD Resident
Rdiology

2. Objectives of imaging in thyroid
nodules
• The objective of imaging is to discriminate between the vast majority of
innocent nodules and the small proportion that are malignant.
• Their incidence increases with age, such that 5-6% of patients over 60
have clinically apparent nodules, and autopsy or careful ultrasound
examination will show that many more older patients have nodular
changes that are clinically occult.
• More than 80 % of thyroid nodules show reduced or absent activity on
scintigraphy, and most of the remainder, which show normal or mildly
increased activity, are non-toxic.
• Malignancy is more likely in those under 20 or over 60 years, in those with
a family history of thyroid cancer, and in patients who have previously
undergone irradiation to the head and neck.
• Solitary nodules are thought to have a higher incidence of malignancy
than multiple nodules, and other pointers to malignancy include hardness
to palpation, rapid growth, laryngeal nerve involvement causing
hoarseness, and the enlargement of lymph nodes in the neck.

3. Selected benign and malignant thyroid
nodules
Benign lesions Malignant lesions
Benign follicular nodule Papillary carcinoma
Adenomatoid nodule Follicular carcinoma
Colloid nodule Hurthle cell carcinoma
Follicular adenoma Poorly differentiated carcinoma
Hurthle cell adenoma Anaplastic/undifferentiated carcinoma
Thyroiditis Medullary carcinoma
Chronic lymphocytic
(Hashimoto)thyroiditis
Lymphoma
Metastasis

4. Nodular Thyroid Disease : Sonographic
Evaluation
• Determine location of palpable neck mass(eg. thyroid or
extra-thyroid).
• Characterize benign versus malignant nodule features.
• Detect occult nodule in patient with history of head and
neck irradiation or multiple endocrine neoplasia(MEN II
syndrome).
• Determine extent of known thyroid malignancy.
• Detect residual, recurrent or metastatic carcinoma.
• Guide fine-needle aspiration of thyroid nodule or cervical
lymph nodes.
• Guide percutaneous-thermal ablation of thyroid nodules,
parathyroids or lymph nodes .

5. Benign cysts
• True epithelial thyroid cysts are rare.
• Most cysts are due to cystic degeneration of
thyroid adenomas and as such a simple cyst
on ultrasound are very uncommon.
• On Usg most cystic lesions will have irregular
thick wall with solid components.
• The presence of a comet tail sign on
ultrasound has been said to be highly specific
sign of a benign colloid nodule.

6. Longitudinal ultrasound scan through the left
lobe of the thyroid demonstrates a simple cyst.

7. Adenoma
• Represents only 5-10% of all nodular disease of thyroid
• Women : Men= 7:1
• Most of them show no thyroid dysfunction.
• Toxic adenomas rarely cause clinical symptoms until they
are greater than 3cm.
• Minority (10%) show hyperfunction ,develop autonomy
,and may cause thyrotoxicosis.
• Most adenomas are solitary, but they may also develop as a
part of a multinodular process.
• The benign follicular adenoma is a true thyroid neoplasm ,
characterized by compression of adjacent tissues and
fibrous encapsulation.

8. Benign follicular adenoma: spectrum of
appearances A.Longitudinal image shows oval
hyperechoic lesion with thick peripheral
halo.B. Longitudinal image shows oval mass
with internal cystic component.C.
homogeneous, hypoechoic, round to oval
masses with a surrounding thin halo, the
capsule of the adenoma; Tr, tracheal air
shadow; C, carotid artery.

9. • Sonographically , adenomas are usually solid masses that
may be hyperechoic, isoechoic or hypoechoic.
• They often have a thick, smooth peripheral hypoechoic
halo resulting from the fibrous capsule and blood vessels
,which can be readily seen by color Doppler imaging.
• Often, vessels pass from the periphery to the central
regions of the nodule, sometimes creating a ‘spoke –wheel
pattern’ .
• This vascular pattern is usually seen in both
hyperfunctioning and poorly functioning adenomas and
this does not allow the detection of hyperfunctioning
lesions.

10. Hyperplastic (adenomatous)
nodule.
Longitudinal ultrasound images. A,
Oval homogeneous nodule
(arrows) with thin, uniform halo. B,
Three hyperechoic nodules,
typical of hyperplasia. C, Solitary
hyperechoic nodule, which was
benign on fine-needle aspiration
biopsy.

11. Colloid Nodule
• Colloid nodules are non-neoplastic benign
nodules occurring within the thyroid gland.
• They form the vast majority of nodular thyroid
disease.
• Colloid nodules are composed of irregularly
enlarged follicles containing abundant colloid.
• Some colloid nodules can be cystic (cystic colloid
nodule) and may contain areas of necrosis ,
hemorrhage and /or calcification.
• A colloid nodule may be single or multiple and
can vary considerably in size.

12. • Usg shows
- Iso to hypoechoic
- May have internal cystic or heterogenous change
- May have calcification
- Multiple echogenic foci ( of inspissated colloid)
with comet tail artifact.
• In `simple' colloid goitre, scintigraphy typically
shows diffuse enlargement with normal or mildly
reduced activity throughout.

13. Colloid cysts. Transverse (A) and
longitudinal (B, C), images of three
patients show the typical appearance
of colloid cysts. Some of the nodules
have tiny echogenic foci that are
thought to be microcrystals. A few of
these foci are associated with
comet-tail artifacts (arrow in A)
posteriorly. Nodules that are mostly
cystic, such as these, are considered
benign. Colloid cysts often contain

14. Inspissated colloid
• Inspissated colloid (colloid crystals)in a thyroid nodule
leads to focal hyperechogenic foci, which can
potentially be confused with microcalcifications.
• Usg shows
- Hyperechoic focus in a thyroid nodule
- Reverberation artifact/comet-tail artifact(this feature is
the most reliable in differentiating inspissated colloid
from microcalcifications)
- Inspissated colloid can vary in size and tend to be larger
than microcalcifications.
- There is overlap in size between the two entites.

15. Multi Nodular Goitre
• A goitre is an enlarged thyroid gland due to multiple
nodules which may have normal , decreased or increased
function.
• When increased activity and hyperthyroidism are present
then the condition is referred to a toxic multinodular goitre
or plummer disease.
• MNG is seen more commonly in females (M:F=1:3) in the
35-50 years of age.
• Patients are usually euthyroid , but the nodules may also be
hypo- or hyperfunctioning ,resulting in systemic symptoms
from hypothyroidism or hyperthyroidism.
• A multinodular goitre is the commonest pathological
condition of the thyroid gland.

16. • Multinodular goitre develop from simple
goitres as a result of repeated instances of
stimulation and involution.
• Most of the nodules are hyperplastic or
adenomatous with varying degree of cystic /
liquefactive degeneration.

17. Multinodular goiter. A, Transverse
image shows enlargement of the right
lobe and isthmus by multiple confluent
hypoechoic and hyperechoic nodules;
Tr, tracheal air shadow. B, Longitudinal
images show multiple confluent
nodules (arrows).
C, Longitudinal dual image shows
enlargement of a lobe by multiple
nodules.

18. Radiographic features
• Ultrasound
- Sonography remains the first radiological investigation to screen the
nodules and look for any suspicion of malignant change in the
nodules which is not uncommon.
- Usually the benign nodules in a multinodular goitre show the
following features:
- Iso-hypoechoic
- Surrounding hypoechoic halo
- Spongiform/honeycomb pattern
anechoic areas may contain colloid fluid which may show echogenic
foci with comet tail artifacts
- Peripheral (eggshell) or coarse calcifications
- Doppler: peripheral vessels are usually noted, may show
intranodular vascularity(mostly in hyperfunctioning nodules)

19. • It is important to screen for the presence of malignant
features (if any) in any of the nodules and subsequent
FNA can be done from suspicious nodule
• Malignant sonographic features
- Hypoechoic solid
- Intranodular blood flow
- Large size : the cut- off is taken as 10mm to warrant a
FNA
- Presence of microcalcifications : almost always
warrants a FNA

20. • Nuclear Medicine
- Tc-99m pertechnate or radioiodine (I-123)
demonstrate an enlarged gland, with
heterogenous uptake.
- Thyroid uptake scan determines the activity of
the gland.

21. • Plain radiography
- Goitre is in the differential for an
anterior/superior mediastinal mass and is
associated with the cervicothoracic sign.
- Associated with deviation of trachea.

22. • CT
-not a primarily modality for diagnosis, but may
be seen incidentally.
- CT may be useful for fully characterizing the
extent of substernal (retrosternal) goitre.
- An enlarged and heterogenous thyroid gland
suggests the diagnosis, which is confirmed by
ultrasound or scintigraphy.

23. Fig. 47.50 (A) Large goitre with an unusually extensive posterior component
surrounding the trachea. (B) The coronal reconstruction shows the
the sublingual and suhnuindibular salivary glands and is further goitre extending
down to the level of the aortic arch. There is only mild
described in Chapter 18. The infrahyoid neck is divided by the narrowing of the
trachea.

24. • The incidence of malignancy in a multinodular
goitre is low but cytology should be performed of
any nodule that is large, dominant or hard or is
growing.
• The characteristics ultrasound appearance of a
multinodular goitre is of mixed solid and cystic
areas within an enlarged gland, with or without
calcification.
• Multinodular goitres may reach an enormous
size.

25. Adenolipoma of thyroid gland
• Also known as thyrolipoma or a thyroid
hamartoma
• Rare , benign fat-containing thyroid lesion.
• These lesions are usually encapsulated and
are composed of varying degrees of follicular
thyroid tissue (thyroid adenoma) and mature
adipose tissue.
• The amount of aft can markedly vary(10-90%)

26. Papillary carcinoma
• 3rd and 7th decade. F>M
• The major route of spread is through
lymphatics to nearby cervical lymph nodes.
• Distant metastasis is rare (2-3%) and occurs to
mediastinum and lungs.

27. Sonography
• Usually appears as a solitary mass usually with an irregular outline,
located in the subcapsular region and demonstrating vascularity.
• Hypoechoic nodules with microcalcifications (tiny punctuate
hyperechoic foci with or without acoustic shadowing).
• Disorganized hypervascularity on color doppler, mostly in well
encapsulated form.
• Cervical lymph node metastasis which may contain tiny punctuate
echogenic foci due to micro-calcifications.
• Cystic lymph node metastsis (tendency to cavitate) in neck occur
almost exclusively with papillary carcinoma.
• Lymph nodes tend to have septations , mural nodules and relatively
thick walls.

28. Papillary carcinoma: small cancer with microscopic correlation. A, Longitudinal image
shows 7-mm, hypoechoic solid nodule containing microcalcifications. B, Microscopic
pathologic image shows microcalcifications, or “psammoma
bodies” (arrow).

29. Papillary thyroid carcinoma: spectrum of appearances. A, Longitudinal image
demonstrates extremely
hypoechoic solid nodule without evidence of calcification.B. hypoechoic
nodules that contain echogenic foci caused by microcalcification.

30. Papillary carcinoma: power Doppler appearances. Blood flow within cancer is
often, but not always, increased. A, Longitudinal image shows 1.5-cm nodule with a
thick, irregular halo. B, Power Doppler image shows that nodule is hypervascular
and has flow in the center and at the periphery.

31. • CT Scan
- CT is best at staging lymph node involvement.
- Involved lymph nodes tend to have;
cystic components-35%
thick nodular walls-40%
septate-60%
purely cystic nodes are uncommon and more frequent in
young patients.
Calcifications may be seen occassionally
the so called lateral aberrant thyroid is actually a lymph
node metastasis from papillary thyroid carcinoma

32. • MRI
- have sensitivity of only 67%(due to half involved
nodes found histologically following surgery ,being
less than 3mm in diameter)
- nodes have tendency to become cystic
-general signal characteristics
T1-hypointense and enhancement best seen with
fat suppression
T2- variable, hypointense(34%), isointense(45%),
hyperintense(21%)

33. • Nuclear imaging
-papillary thyroid cancer usually concentrates
radioiodine, but not pertechnate.
-FDG-PET
-FDG-avid
-incidental FDG – avid thyroid nodules have
almost 40% risk of being a primary thyroid
malignancy.

34. Follicular carcinoma
• 5-15%
• Subtypes
-classic follicular thyroid carcinoma
-Hurthle cell variant
-Insular variant
• Sonographically can’t be differentiated from follicular
adenoma.
• Hypoechoic nodule with irregular tumor margins.
• Thick, irregular halo.
• Tortous or chaotic arrangement of internal blood
vessels on color doppler.

35. Follicular neoplasms: benign and malignant in same patient. A, Left lobe, and B,
right lobe, of the thyroid show round, homogeneous hypoechoic masses that appear
identical except for size differences on transverse images; Tr, tracheal
air shadow. The smaller mass was malignant and the larger mass benign.

36. Medullary carcinoma
• Only 5% of thyroid cancer
• Derived from parafollicular or C cells.
• Secretes calcitonin –useful serum marker.
• High incidence of metastasis to lymph nodes.
• Sonography
-similar to papillary carcinoma-hypoechoic solid mass
with calcifications(often, but coarse than papillary
carcinoma) in primary as well as metastatic lymph nodes.
Local invasion and cervical lymphadenopathy are also
more common.
Involved lymph nodes typically calcify.

37. Medullary carcinoma.
The appearance of this
solid hypoechoic
nodule (cursors) is very
similar to that of
papillary carcinoma.}

38. • CT
-both primary and metastatic lesions usually
have irregular dense calcific foci within.
• Nuclear imaging
-radioactive iodine- lesions do not concentrate
radioactive iodine since the tumor does not
arise from thyroid follicular cells.

39. Anaplastic thyroid carcinoma
• Occurs in elderly
• <5% of tumors
• Worst prognosis
• Presents as a rapidly enlarging mass extending
beyond gland and invading adjacent
structures.
• Show aggressive local invasion of muscle and
vessels.

40. • Sonography
-hypoechoic masses often seen to encase or
invade blood vessel and neck muscles (CT or
MRI demonstrates the tumor more accurately
owing to their large size)

42. Metastatic disease
• Metastatic disease involving the thyroid is
uncommon.
• The common primary sites include melanoma
, breast and renal cell carcinoma.

43. Thyroid metastasis from renal cell carcinoma. A, Longitudinal (gray scale), and B,
power Doppler, images show a 1-cm solid vascular mass.

44. Lymphoma
• 4% of all thyroid malignancies
• Mostly Non-Hodgkin’s type.
• Elder females
• In 70-80% cases arises from preexisting
chronic lymphocytic thyroiditis(HASHIMOTO’S
thyroiditis) with subclinical or overt
hypothyroidism.

45. • Sonography
-markedly hypoechoic lobulated mass
-hypovascular or show blood vessels with
chaotic distribution and ateriovenous shunts.
-large areas of cystic necrosis may occur as well
as ancasement of adjacent neck vessels.
Adjacent thyroid parenchyma heterogenous due
to associated chronic thyroiditis.

46. Lymphoma. A, Transverse image of left lobe of the thyroid shows diffuse
mass enlarging the lobe and extending into the soft tissues (arrows)
surrounding the common carotid artery (c); Tr, tracheal air shadow. B,
Contrast-enhanced CT scan shows a hypovascular mass in the left thyroid
lobe and soft tissue encasement of the carotid artery.

47. Hurthle cell tumors
• Hurthle cell tumors are very rare.
• They have been considered benign lesions in the
past but may exhibit malignant characteristics
with metastatic spread to lymph nodes and lung.
• This is seen more frequently(80%) in lesions
measuring greater than 4cm in diameter.
• The tumors are of mixed echogenicity on
ultrasound, usually solid and often ill defined
with no calcification.

49. Reliability of Sonographic Features In
Differentiation of Benign From
Malignant Thyroid NodulesFeatures Benign Malignant
SHAPE
Wider than tall +++ ++
Taller than wide + ++++
INTERNAL CONTENTS
Purely cystic content ++++ +
Cystic with thin septa ++++ +
Mixed solid and cystic +++ ++
Comet tail artifact +++ +
ECHOGENICITY
Hyperechoic ++++ +
Isoechoic +++ ++
Hypoechoic +++ +++
Markedly hypoechoic + ++++

50. Feature Benign Malignant
HALO
Thin halo ++++ ++
Thick incomplete halo + +++
Absent + +++
MARGIN
Well defined +++ ++
Poorly defined ++ +++
Spiculated + ++++
CALCIFICATION
Egg shell calcification +++ ++
Coarse calcification +++ +
Microcalcification ++ ++++

51. Feature Benign Malignant
DOPPLER
Peripheral flow pattern +++ ++
Internal flow pattern ++ +++
SONOELASTOGRAPHY
Patterns 1 and 2 ++++ +
Patterns 3and 4
[+rare<1%, ++ low probability
<15% , +++ intermediate probability
16-84%, ++++ high probability
>85%]
+ +++

52. Characteristics of a Thyroid Nodule
Compsition
• Composition describes the internal components of the
nodule,that is,the presence of soft tissue or fluid ,and the
proportion of each.
• Solid : Composed entirely or nearly entirely of soft tissue
with only a few tiny cystic spaces.
• Predominantly solid: Composed of soft tissue components
occupying 50% or more of the volume of nodule.
• Predominantly cystic: Composed of soft tissue components
occupying less than 50% of the volume of the nodule.
• Spongiform : composed predominantly of tiny cystic
spaces.

53. Benign nodule feature. Longitudinal images. Extensive honeycomb-like or
cystic changes, with nodules showing
A, larger cystic spaces, and B, smaller cystic spaces. These features indicate a
very high probability of a benign process.

54. Echogenicity
• Definition : level of echogenicity of the solid,
noncalcified component of the nodule ,relative to
surrounding thyroid tissue.
• Hyperechoic : Increased echogenicity relative to
thyroid tissue
• Hypoechoic : decreased echogenicity relative to thyroid
tissue.
• Very hypoechoic: decreased echogenicity relative to
adjacent neck musculature.
• Isoechoic : similar echogenicity relative to thyroid
tissue

56. Shape term: Taller than wide.
• Definition : a taller than wide shape is defined
as a ratio of >1 in the anteroposterior
diameter to the horizontal diameter when
measured in transverse plane.

58. Size
• How the nodules should be measured:
• Use maximal diameter on the basis of
longitudinal, antero-posterior and transverse
measurements in centimeters or millimeter.

59. Margins
• Definition : refers to the border or interface
between the nodules and the adjacent thyroid
parenchyma or adjacent extra-thyroidal
structures.
• Ill defined : border of the nodule is difficult to
distinguish from thyroid parenchyma, the
nodule lacks irregular or lobulated margins.

61. • Lobulated : border has focal rounded soft
tissue protrusions that extend into the
adjacent parenchyma. The lobulations may be
single or multiple and may vary in conspicuity
and size (small lobulations are referred to as
microlobulated)
• Extrathyroid extension : Nodule extends
through the thyroid capsule.

63. • Halo : Border consists of a dark rim around the
periphery of the nodule. The halo can be described as
completely or partially encircling the nodule. In the
literature, halos have been further characterized as
uniformly thin ,uniformly thick or irregular in thickness.
• Smooth : uninterrupted ,well defined ,curvilinear edge
typically forming a spherical or elliptical shape.
• Irregular : the outer border of the nodule is spiculated
,jagged or with sharp angles with or without clear soft
tissue protrusions into the parenchyma. The
protrusions may vary in size and conspicuity and may
be present in only one portion of the nodule.

64. (A) A solid nodule seen within the thyroid.
(B) Colour flow is
seen around the periphery of this benign
nodule.

65. Abnormal partially cystic mass within the
thyroid in another patient with abnormal
vascularity proved to be a papillary carcinoma.

66. • Category 6: Echogenic foci
• Definition: refers to focal regions of markedly
increased echogenicity within a nodule
relative to the surrounding tissue. Echogenic
foci vary in size and shape and may be
encountered alone or in association with
several well known posterior acoustic
artifacts.

67. Contrast-enhanced sonography to differentiate benign from malignant fluid-filled
thyroid nodules with internal septations or solid projections. A, Conventional B-
mode sonogram of right thyroid lobe demonstrates
large, mixed solid and cystic nodule; Tr, tracheal air shadow; C, common carotid
artery. B, Contrast-enhanced sonogram. After
administration of contrast material, the internal contents are no longer visible
because they lack enhancement, indicating that the contents
were likely colloid and blood products.

68. Contrast-enhanced sonography to differentiate benign from malignant fluid-filled thyroid
nodules with internal septations or solid projections. C, Conventional B-mode sonogram
in longitudinal plane demonstrates a nodule (arrow) arising from the posterior wall. D,
Contrast-enhanced longitudinal sonogram shows that the nodule remains visible,
indicating enhancement after contrast enhancement. The lesion was a cystic papillary
carcinoma.

69. • Punctuate echogenic foci: “Dot-like” foci having
no posterior acoustic artifacts.
• Kwak et al defined punctuate foci/calcifications as
being <1mm. Most authors define this feature on
the basis of appearance alone.
• Macrocalcifications : when calcifications become
large enough to result in posterior acoustic
shadowing, they should be considered
macrocalcifications. Macrocalcifications may be
irregular in shape.

70. • Peripheral calcifications : These calcifications occupy
the periphery of the nodule. The calcification may not
be completely continuous but generally involves the
majority of the margin. Peripheral calcifications are
often dense enough to obscure the central
components of the nodule.
• Comet tail artifacts: A comet tail artifact is a type of
reverberation artifact. The deeper echoes become
attenuated and are displayed as decreased width ,
resulting in a triangular shape.
• If an echogenic focus doesn’t have this feature, a
comet- tail artifact should not be described.

72. “Eggshell” calcification. Peripheral
(eggshell) calcification was previously
thought to indicate a benign nodule,
but malignant nodules may have the
appearance shown on these longitudinal
images. A, Coarse peripheral calcification
(arrows) casts a large acoustic shadow. B,
Eggshell calcification and a typical
appearance of colloid cyst on the right
side in another patient. C, Hypoechoic
solid mass caused by papillary carcinoma
surrounds area of eggshell calcification.

73. ATA guidelines for assessment of
thyroid nodules
• American Thyroid Association(ATA) guidelines are
meant to improve inter and intra-reader
consistency during assessment of thyroid nodules
on ultrasound , and to facilitate communication
with referring endocrinologist.
• The 2015 guidelines stress the importance of the
sonographic pattern of the nodule for risk
stratification.
• This , as well as the size of the nodule, are the
two main criteria for FNA.

74. • Initial evaluation
• Serum thyrotropin (TSH) should be obtained
- If TSH is below the normal limits, thyroid scintigraphy
should be pursued
• An incidental finding of focal FDG uptake in a >1cm
thyroid nodule is concerning and FNA is warranted.
- If <1cm the nodule may be monitored similarly to a
subcentimetr thyroid nodule with a high risk
sonographic pattern
- If the thyroid demonstrates diffuse uptake compatible
with chronic lymphocytic thyroiditis, further imaging or
FNA is not warranted.

75. • Sonographic pattern
On a thyroid ultrasound, a nodule is classified into one of
five categories
- Benign pattern(0% risk) : no biopsy
- Very low suspicion pattren(<3%): biopsy if >=2cm(or
ultrasound observation)
- Low suspicion pattern (5-10% risk): biopsy if >= 1.5cm
- Intermediate suspicion (10-20%risk): biopsy if >=1cm
- High suspicion pattern(>70-90% risk): biopsy if >=1cm

76. • Benign pattern(0% risk)
- Completely cystic nodules with well defined
walls

77. • Very low suspicion pattern(<3% risk)
- Spongiform nodules and nodules with
interspersed cystic spaces, without any of the
features in more suspicious pattern

79. • Low suspicion pattern(5-10% risk)
- Isoechoic or hyperechoic nodule
- Partially cystic nodule with a peripheral solid
component
- None of the following features
.microcalcifications
.irregular margins
.extrathyroidal extension
.taller than wide

80. • Intermediate suspicion pattern(10-20% risk)
- Hypoechoic solid nodule with smooth margins
- None of the following features:
.microcalcifications
.irregular margins
.extrathyroidal extension
.taller than wide

81. • High suspicion pattern(>70-90% risk)
- Solid hypo-echoic nodule (or solid hypo-echoic
component of a partially cystic nodule), with at least
one of these features:
- Micro-calcifications
- Irregular margins(infiltrative, micro-lobulated)
- Extra-thyroidal extension
- Taller than wider
- Rim calcifications with an extrusive soft tissue
component
- lymphadenopathy

83. TIRADS:OVERVIEW
• TIRADS system is ultrasonographic
classification for thyroid nodules.
• The terminology “thyroid imaging reporting
and data system “(TIRADS) was first used by
Hovarth et al in 2009

84. The Goals
• Stratify the risk of malignancy of a lesion
based on the US features of the lesion
• Standardize and simplify the reports, allowing
effective communication between radiologists
,cytologists and clinicians.
• Improve the quality of care and cost-
effectiveness , avoiding unnecessary biopsies.

85. ACR Thyroid Imaging Reporting And
Data System (ACR TI-RADS)
• ACR TI-RADS is a reporting system for thyroid
nodules on ultrasound proposed by the
American College Of Radiology(ACR)
• This uses a standardized scoring system for
reports providing users with
recommendations for when to use fine needle
aspiration(FNA) or ultrasound follow up of
suspicious nodules, and when to safely leave
alone nodules that are benign/not suspicious.

86. Radiographic features
• Ultrasound
- Scoring is determined from five categories of
ultrasound findings.
- The higher the cumulative score, the higher the
TR (TIRADS) level and likelihood of malignancy.
- If multiple nodules are present only the four
highest scoring nodules(not necessarily the
largest) should be scored, reported and followed
up.
- One score is assigned from each of the following
categories:

87. • Composition :(choose one)
- Cystic or completely cystic : 0 points
- Spongiform : 0 points
- Mixed cystic and solid : 1 point
- Solid or almost completely solid :2 points
- Predominantly cystic or spongiform nodules are
inherently benign. If these features are present
no further points will be added(automatically
TR1)

88. • Echogenicity : (choose one)
- Anechoic : 0 points
- Hyper or isoechoic :1 point
- Hypoechoic :2 points
- Very hypoechoic : 3points

89. • Shape (choose one)
- Assessed on the transverse plane
- Wider than tall : 0 points
- Taller than wide : 3 points

90. • Margin (choose one)
- Smooth : 0 points
- Ill-defined : 0 points
- Lobulated/ irregular : 2 points
- Extra-thyroidal extension :3 points

91. • Echogenic foci (choose one or more)
- None : 0 points
- Large comet tail artifact : 0 points
- Macro-calcifications : 1 point
- Peripheral/rim calcifications : 2points
- Punctuate echogenic foci :3 points

92. Scoring and Classification
• TR 1: 0 points
-benign
• TR 2 : 2 Points
-not suspicious
• TR 3 : 3 Points
-mildly suspicious
• TR 4 : 4-6 Points
-moderately suspicious
• TR 5 : >=7 Points
-highly suspicious

93. Recommendations
• TR1 – no FNA required
• TR2 – no FNA required
• TR3 - >=1.5 cm follow up, >=2.5cm FNA
-follow up : 1,3 and 5 years
• TR4 - >= 1cm follow up, >=1.5cm FNA
-follow up: 1,2,3 and 5 years
• TR5 - >=0.5cm follow up, >=1cm FNA
-annual follow up for upto 5 years

95. • Biopsy is recommended for suspicious lesions (TR3-
TR5) with the above size criteria.
• If there are multiple nodules, the two with the highest
ACR TI-RADS grades should be sampled (rather than
the two largest).
• Interval enlargement on follow up is felt to be
significant if there is an increase of 20% and 2 mm in
two dimensions , or a 50% increase in volume.
• If the ACR TI-RADS level increases between the scans,
an interval scan the following year is again
recommended.

96. Risk of malignancy
• The projected risk of malignancy in the original 2017
paper was based on partial analysis of 3433 nodules
with cytological results.
• The final analysis demonstrated a stepwise increase for
each pint awarded by ACR TI-RADS, with each category
validated. The published malignancy rates are:
- TR1 :0.3%
- TR2 :1.5%
- TR3 :4.8%
- TR4 :9.1%
- TR5 :35%

97. US features of benign thyroid nodules
• Features suggesting benignity
• Uniform halo around the nodule
• Predominantly cystic
• Avascular
• Enlarged thyroid with multiple nodules

98. US features of malignant thyroid
nodules
• Features suspicious for malignancy
• Specific features
-micro-calcifications
-extension beyond thyroid margin
-cervical lymph nodes metastasis
-taller than wide in transverse plane
-markedly hypo-echoic

99. • Less specific features
-no halo around nodule(per nodular thyroid
parenchyma invasion)
-ill defined or irregular margin
-solid (partially cystic nodule with eccentric
location of the fluid portion and lobulation of
the solid component)
-increased central vascularity (intranodal
vascularity)

100. Incidental thyroid nodules
• Incidental thyroid nodules also called thyroid
incidentalomas , are discrete lesions in the thyroid
gland found on cross sectional imaging performed for
indications other than thyroid evaluation.
• Incidental thyroid nodules are identified at different
rates depending on the modality used.
-extra-thyroidal ultrasound (eg. of the carotid arteries):
67%
-CT (eg. Of the neck ,cervical spine or chest):25%
-MRI: 18%
-FDG-PET:<2%

101. Risk of malignancy
• Around the one- third of FDG-PET positive
nodules will be malignant
• Cross sectional modalities (CT/MRI) only
reach 12% (in some studies)
• Ultrasound is lower still a <2% malignancy in a
population based study, illustrating the high
proportion of benign nodules.

102. American College Of Radiology
Recommendations
• A nodule meeting any of the following criteria is
recommended for further evaluation by thyroid US:
- Focal thyroid uptake on FDG-PET or other nuclear
medicine scans
- Thyroid nodule with local tissue invasion
- Thyroid nodule with suspicious lymph nodes(enlarged,
cystic, calcified ,or hyper-enhancing)
- Thyroid nodule >=1cm (in axial plane) in patients <35
years old.
- Thyroid nodule >=1.5cm (in axial plane) in patients
>=35 years old

103. • When multiple thyroid nodules are present, the criteria
apply to the largest nodule.
• When the initial finding is a FDG-avid focus on PET, fine
needle aspiration is recommended regardless of the
ultrasound findings.
• Dedicated thyroid ultrasound would also be indicated if
suspicious features happen to be captured on the non
thyroidal ultrasound, such as:
- Micro-calcifications
- Marked hypo-echogenicity
- Lobulated/irregular margins
- Taller-than-wide shape

104. Biopsy guidence
• Indications
-non palpable suspected nodule with
inconclusive physical examination.
-patients at high risk of developing thyroid
cancer, normal gland by physical examination
but sonography demonstrates a nodule.
-previous non diagnostic / inconclusive biopsy.

106. • References
-Diagnostic ultrasound Rumack 5th edition
-ACR/ATA guidelines on thyroid nodules
incidentalomas and TIRADS
-various internet sources

107. THANK YOU