THYROID ULTRASOUND

DR/ Wafik Ebrahim, MDAssistant Professor of Radiodiagnosis

Faculty of MedicineAlazhar University

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

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. Do not forget: Any thyroid pathology can occur in this tract. Search for it.

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. .

Scanning technique: 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. Ask patient to swallow to detect movement

and lower hiddne lesions. Do not forget lymph node assessment.

Measurement :

Measurement :

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.

Measurement :

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?.

Echogenecity:Examine for echogenecity in Long plane!.

Which is Normal?

Echogenecity :

Homogeneous Heterogeneous

Echogenecity :

Echogenecity :

In normal gland:Few vessels can be seen.

In thyrotoxic or early inflammatory process:Vacularity increases.

Vascularity :

Normal Hypervascular

Vascularity :

Focal lesion assessment : 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.

Reporting: 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

Artifacts: 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

Posterior enhancement Back shadow

Artifacts:

Microcalcifications do not produce back shadow

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

Diffuse thyroid disease :

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

Hashimoto thyroiditis:

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.

Diffusely enlarged gland with fibrous septae and high vascularity

(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

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

Chronic end stage disease: small atrophic with fibrous septae

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.

Grave’s disease:

Diagnosis is made when patient presents with diffuse thyroid enlargement and hyperthyroidism (thyrotoxic goiter).

Secondary finding may present (orbitopathy).

Grave’s disease:

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.

Grave’s disease:

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.

Grave’s disease:

Grave’s disease:

Grave’s disease:

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.

De Quervain Thyroiditis:Subacute thyroiditis, Non suppurative thyroiditis:

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.

De Quervain Thyroiditis:

De Quervain Thyroiditis:

De Quervain Thyroiditis:

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.

Acute suppurative thyroiditis

Acute suppurative thyroiditis

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.

Atrophic thyroiditis:

Atrophic thyroiditis:

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

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.

Goiter:

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

Goiter:

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 .

Multinodular Goiter:

Do not forget searching for retrosternal extension .

Multinodular Goiter:

Thyroglossal duct cyst 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.

Thyroglossal duct cyst

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.

Thyroid adenoma:

Thyroid adenoma: 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

Thyroid adenoma:

Types: Differentiated carcinoma:

○ Papillary (70%).○ Follicular and carcinoma (10%).

Aggressive tumors:○ Medullary carcinoma (5%).○ Anaplastic carcinoma (5%).

Others including lymphoma and metastasis (10%).

Malignant Thyroid mass

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 malignancyEgg shell calcifications benignity.

Thyroid malignancy:

Thyroid malignancy: Role of imaging:

Evaluation of thyroid capsule integrity.Detection of infiltration of surrounding

structures. Identification of malignant lymph nodes.

Differentiated carcinoma:

Invasive mass with thyroid capsular invasion and metastatic lymph nodes.

Hypoechoic mostly solid tumor but cystic changes are seen in follicular type

Malignant thyroid:

Medullary carcinoma Anaplastic carcinoma

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.

Thyroid nodules:

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.

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

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-wideIrregular borders

MicrocalcificationsMarkedly 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.

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

Parathyroid gland: Adenoma

Parathyroid gland: Adenoma

Diagnosis?Signs (2)?

Quiz 2Diagnosis:

Quiz 3Diagnosis?

Quiz 4Diagnosis?

Quiz 5cyst or solid nodule?

Thank You