Thyroid US

1. DR/ Wafik Ebrahim, MD
Assistant Professor of Radiodiagnosis
Faculty of Medicine
Alazhar University

2.  Ultrasonography is the single-most
valuable imaging modality in the evaluation
of the thyroid gland. In many radiology
departments it is one of the most frequently
performed ultrasound examinations.
 Why?
 Simple, painless, no radiation, no contrast
 Superficial position of gland:
 Development of high resolution machines

3. Anatomy
 Thyoroid is an endocrine gland located in
anterior inferior part of the neck.
 It is butterfly-shaped and is built by two
cone-like lobes and isthmus between them.
 Pyramidal lobe is seen (in 50% of patients)
extending from midline of isthmus to the
root of the tongue. It is remnant from
thyroglossal duct.

4. Thyroid and
parathyroid glands
•Thyroid glands:
 Two lobes connected by the
isthmus wrapped around the
trachea.
•parathyroid gland:
 Four lobes at the posterior surface
of thyroid gland. .

6.  Use linear high frequency probe (at least 7
MHz) with color Doppler.
 Patient should be laid symmetrically on the
back on a high table with stretched out neck.
 Examine in transverse plane (for width and
thickness) and longitudinal plane for length.
 For any lesion, consider the two planes.

9.  Length 4-6cm.
 Width and thickness 1.3-1.8cm (not > 20mm).
 Isthmus: 4-6mm (not > 10mm.
 Consider volume:
 Males: up to 25ccm.
 Females: up to 20ccm.
○ Automatically generated.
○ Or use correction factor (three diameters X 0.53 ). Then
summation of both lobes.
 Roughly enlarged gland has bulging anterior
surface.

10.  Normal gland
 Less echogenic than adjacent subcutaneous fat
and more echogenic than surrounding muscles.
 Homogeneous.
 Diffuse low echogencity or heterogenity
means diffuse disease.
Examine for echogenecity in Which
plane?.
Examine for echogenecity in Long
plane!.

11. Which is Normal?

12. Homogeneous Heterogeneous

14.  In normal gland:
 Few vessels can be seen.
 In thyrotoxic or early inflammatory process:
 Vacularity increases.

15. Normal Hypervascular

16.  Location:
 Right, left or isthmus.
 Upper, middle or lower part of the lobe.
 Measurement: In three planes.
 Echogenecity: malignant lesions mostly hypoechoic.
 Echostructure: cystic changes, calcifications.
 Vascularity: no flow, intranodular flow, perinodular, or
both (suspecious for malignancy).
 Elastography if available: malignant lesions are
stiffer.

17.  Used device:
 Size of gland: (remember retrosternal extension)
 Echogenecity:
 Vascularity:
 Focal lesion assessment:
 Lymph nodes assessment.
 Conclusion:
 TIRADS is developed (Thyroid Imaging Reporting
and Data system:
 Recommendatios

18.  Artifacts are images which appear on the
display and do not represent actual physical
structures.
 These shadows or enhanced representation of
tissue elements tell a story.
 Posterior enhancement:
 Back shadowing:
Cyst
calcifications

19. Posterior enhancement Back shadow

20. Microcalcifications do not produce back
shadow

21. The uniform character of tissues result in even
transmission of sound waves with little attenuation
giving posterior enhancement (pleomorphic
adenoma)

23.  Chronic autoimmune-mediated lymphocytic
inflammation of thyroid gland.
 Non-specific enlargement of the gland without
calcification or necrosis.
 Most common form of thyroiditis.
 More common in female
:

24.  Real time US:
 Early Stages: Non-specific:
○ Enlarged Heterogeneous Hypoechoic gland.
○ Hypoechoic foci may be seen (micronodulation).
 Late: small hypoechoic heterogenous fibrotic
gland.
 Uncommon: focal disease within normal
gland.
 Color Doppler:
 Early: increased vascularity.
 Late: absent blood flow signal.

25. Diffusely enlarged gland with
fibrous septae and high
vascularity

26. (A) “micronodulation,” Diffuse, illmarginated
innumerable small hypoechoic nodules (arrow)
surrounded by echogenic stroma termed
(B) Swiss-cheese appearance. Diffuse small
hypoechoic lesions (arrow) in the thyroid create
pseudocystic appearance

28. Localized form of
Hashimoto’s
Nodule consisting of
bright blocks separated
by dark bands.
The background thyroid
is hypoechoic and
coarsened with
micronodularity typical
of diffuse Hashimoto’s
thyroiditis.

29. Chronic end stage disease:
small atrophic with fibrous
septae

30.  It is an autoimmune disease.
 Binding of thyroid autoantibodies to the
thyrotropin receptor on the follicular
cells. Autoantibody binding stimulates
the cells as though TSH triggered the
receptor.
 The result is increased hormone
synthesis and secretion, and growth of
the thyroid gland.

31.  Diagnosis is made when patient
presents with diffuse thyroid
enlargement and hyperthyroidism
(thyrotoxic goiter).
 Secondary finding may present
(orbitopathy).

32.  There is no gray scale specific finding for the
disease.
 Suggestive signs are diffuse enlargement,
convex bowing of the anterior gland margin,
and mild textural coarsening.
 Hypoechoic pattern is also noted due to high
blood flow, high cellularity on expense of
colloid contents and lymphocytic infiltration.

33.  High vascularity with high velocity flow is
characteristic (> 60cm/sec PSV).
 DD from early Hashimoto’s thyroiditis is difficult
however, here the gland is less hetrogeneous
and less lobular and has higher velocity vessels.
 Normally velocity in inferior thyroid A is 10-
15cm/sec and in the parenchymal vessels is 3-
5cm/sec.
 In Grave’s disease 10-15 fold increase in PSV.

36.  Is an uncommon disease that occurs most
often in women in their second to fifth
decades of life.
 This disease usually presents with thyroid
tenderness, a low grade fever, and
occasional dysphagia.
 The disease resolves spontaneously, usually
without thyroid function abnormalities.

37.  The characteristic ultrasound findings for this
disorder are ill- defined, moderately, or
markedly patchy hypoechoic areas of thyroid
parenchyma that show little to no vascular
flow on color Doppler interrogation.
 Hypoechoic areas tend to elongate along the
long axis of the thyroid.

40.  The thyroid is normally very resistant to
infection. Due to a relatively high
amount of iodine in the tissue, as well as
high vascularity and lymphatic drainage.
 Despite all this, a persistent fistula from
the piriform sinus may make the thyroid
susceptible to infection and abscess
formation.

42.  It is usually autoimmune where the
antibodies block the receptors of
follicular cells with resultant gland
atrophy and loss of function
(contradictory to Grave’s disease where
the antibodies stimulate the receptors) .
 It may be also end stage of thyroiditis.

43. Atrophic thyroiditis. The thyroid gland is small to
normal in size and diffusely hypoechoic with
micronodulation.

44.  Diffuse enlargement of the thyroid gland.
 It may be simple diffuse (non-nodular) or
Nodular goiter .
 The simple form eventually develops into
nodular form.
 The cause of simple goiter is multifactorial and
involves complex interactions between
environmental (iodine intake), genetic, and
endogenous (female gender) factors.

45. Simple diffuse goiter. A transverse ultrasound image shows a
moderately to markedly enlarged thyroid gland with normal
homogenous thyroid echogenicity.

46.  The gland is enlarged yet well marginated.
 Calcification, necrosis, cystic degeneration
and hemorrhage may be seen.
 US  shows focal or diffuse replacement of
the thyroid parenchyma by closely opposed,
isoechoic solid nodules and cystic nodules
without normal intervening parenchyma and
background heterogeneity shows
 Hemorrhage may be seen as high echogenecities
within the cysts.

47. Do not forget searching for
retrosternal extension.

48.  The most common congenital neck cyst.
They are typically located in the midline
and are the most common midline neck
masses in young patients.
 Ultrasound: Unless infected, they are
usually anechoic and the walls are thin,
without internal vascularity.
 If infected, the fluid may be turbid.

50.  Thyroid adenoma: (true neoplasm with
complete capsule): Single well defined
intrathyroid mass within normal gland.
 Adenomatous polyp: adenomatous
hyperplasia with incomplete capsule: less
distinct and may be multiple.

51.  US: hypo, iso or hyperechoic nodule:
 Thyroid adenoma: has thick smooth hypoechoic
halo.
 Adenomatous polyp: Has incomplete halo.
 Signs of benignity:
Thin halo, regular margin and coarse
calcifications.
 Color Doppler:
 Thyroid adenoma: peripheral vascularity extending
toward center (Spoke and wheel appearance).
 Adenomatous polyp: more diffuse vascularity

53.  Types:
 Differentiated carcinoma:
○ Papillary (70%).
○ Follicular and carcinoma (10%).
 Aggressive tumors:
○ Medullary carcinoma (5%).
○ Anaplastic carcinoma (5%).
 Others including lymphoma and metastasis
(10%).

54.  Unfortunately the appearance of thyroid
malignancy is usually non-specific.
 Nodules with irregular margin or mass
invading surrounding structures should
alert for malignancy.
 60% of malignant nodules have irregular
border and also 45% of benign nodules
have irregular border.
 Calcifications:
 Microcalcifications  malignancy
 Egg shell calcifications  benignity.
Thyroid malignancy:

55. Thyroid malignancy:
 Role of imaging:
 Evaluation of thyroid capsule integrity.
 Detection of infiltration of surrounding
structures.
 Identification of malignant lymph nodes.

56. Differentiated carcinoma:
 Invasive mass with
thyroid capsular
invasion and
metastatic lymph
nodes.
 Hypoechoic mostly
solid tumor but cystic
changes are seen in
follicular type

57. Malignant thyroid:
Medullary carcinoma Anaplastic carcinoma

58.  Colloid nodules. These are one or more overgrowths of
normal thyroid tissue. These growths are not cancerous
(benign).
 Thyroid cysts.
 Inflammatory nodules. These nodules develop as a result of
chronic inflammation of the thyroid gland.
 Multinodular goiter.
 Hyperfunctioning thyroid nodules.
 Thyroid cancer. Of the nodules that can form as the thyroid
gland enlarges, fortunately, less than 5 percent are
cancerous.

59. TIRADS: OVERVIEW
 TIRADS system is ultrasonographic classification for thyroid nodules.
 The terminology “Thyroid Imaging Reporting and Data System” (TIRADS) was first used
by Horvath et al in 2009, drawing inspiration from the “Breast Imaging and Reporting
Data System” (BIRADS) of the American College of Radiology.
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 quality of care and cost-effectiveness, avoiding unnecessary biopsies.

60. TIRADS by Horvath et al.
Horvath E, Majilis S, Rossi R, Franco C, Niedmann J, Castro A & Dominguez M. An ultrasonogram reporting system for thyroid
nodules stratifying cancer risk for clinical management. Journal of Clinical Endocrinology and Metabolism 2009 90 1748–1751
Description Risk of malignancy
TIRADS 1 Normal thyroid gland 0
TIRADS 2 Benign 0
TIRADS 3 Probably benign <5%
TIRADS 4A Suspicion for malignancy 5-10%
TIRADS 4B Intermediate suspicion for malignancy 10-80%
TIRADS 5 Highly suggestive of malignancy >80%
TIRADS 6 Biopsy proven malignancy

61. TIRADS by Russ et al
Authors proposed the following flowchart to assign a nodule to one of TIRADS categories
Suspect pattern Benign pattern
Thyroid Nodule
High Suspect:
Taller-than-wide
Irregular borders
Microcalcifications
Markedly hypoechoic
High stiffness on
sonoelastography
Very probably
No signs of high
suspect.
Mildly hypoecoic
1-2 signs,
no metastatic lymph
nodes
3-5 signs and/or
metastatic lymph
nodes
TIRADS 4ATIRADS 4BTIRADS 5
Constantly
No sign of high
suspicion: regular
shape and borders,
no micro-
calcifications and
iso/hyperecoic
- Simple cyst
- Spongiform nodule
- “white knight”
- isolated macro-
calcifications
- Nodular
hyperplasia
TIRADS 2TIRADS 3
Russ B, Royer B, Bigorgne C, et al. Prospective evaluation of thyroidimaging reporting and data system on 4550 nodules with and without elastography. Eur J Endocrinol.
2013;168:649–655.

63.  It is well defined small mass in expected location.
 Associated hyperparathyroidism.

65. Diagnosis?
Signs (2) ?

66. Quiz 2
Diagnosis:

67. Quiz 3
Diagnosis?

68. Quiz 4
Diagnosis?

69. Quiz 5
cyst or solid nodule?