Ultrasonography of thyroid nodules: a pictorial review

Abstract

Thyroid nodules are a common occurrence in the general population, and these incidental thyroid nodules are often referred for ultrasound (US) evaluation. US provides a safe and fast method of examination. It is sensitive for the detection of thyroid nodules, and suspicious features can be used to guide further investigation/management decisions. However, given the financial burden on the health service and unnecessary anxiety for patients, it is unrealistic to biopsy every thyroid nodule to confirm diagnosis. The British Thyroid Association (BTA) has recently produced a US classification (U1–U5) of thyroid nodules to facilitate the decision-making process regarding the need to perform fine-needle aspiration cytology (FNAC) for suspicious cases. In this pictorial review, we provide a complete series of sonographic images to illustrate benign and malignant features of thyroid nodules according to the U1–5 classification. Specifically, we highlight morphologic characteristic of the nodule, including its echo signal in relation to its consistency, nodular size, number and contour. Additional diagnostic features such as halo, colloid, calcification and vascular patterns are also discussed in detail. The aim is to assist radiologists and clinicians in recognising sonographic patterns of benign, suspicious and malignant nodules based on U1–5 criteria, and in planning for further investigations.Main messages• Ultrasound is sensitive in identifying suspicious features, which require aspiration.• Whether nodules require aspiration should be based on sonographic features and clinical findings.• U1–5 classification of sonographic findings can help determine whether aspiration is necessary.

Investigation of thyroid nodules: A practical algorithm and review of guidelines

“…Meta‐analysis has shown that spongiform appearance on ultrasound has the highest diagnostic OR for benign characterization, and in addition to cystic nodules are the only 2 features that can prevent the need for an FNA biopsy . Similarly, reports estimate 10.0% and 99.7% sensitivity and specificity, respectively, for benign disease …”

“…In order to properly stratify risk of malignancy, ultrasound imaging findings should be corroborated by relevant findings on clinical history and examination. Commonly cited clinical features increasing likelihood of cancer include familial history of differentiated thyroid cancer, multiple endocrine neoplasia type II, or medullary thyroid carcinoma, any previous radiation exposure, male sex, age under 20 or over 60 years, a firm or fixed nodule, and rapid nodular growth . Physical examination findings that suggest malignancy include vocal cord paralysis, regional lymphadenopathy, dysphonia, and fixation to surrounding tissue .…”

Lumps and Bumps of the Neck in Children—Neuroimaging of Congenital and Acquired Lesions

“…Intralesional punctate echogenic foci of calcification and intranodular vascularity may be detected . In case of a suspicious thyroid nodule, ultrasound‐guided biopsy is an important diagnostic tool …”

“…47 Suspicious imaging finding on US include a pronounced hypoechoic thyroid mass, a predominantly solid nature, disrupted eggshell calcifications, an irregular border, and "taller than wide" in shape. 48 Intralesional punctate echogenic foci of calcification and intranodular vascularity may be detected. 45,47 In case of a suspicious thyroid nodule, ultrasound-guided biopsy is an important diagnostic tool.…”

“…45,47 In case of a suspicious thyroid nodule, ultrasound-guided biopsy is an important diagnostic tool. [45][46][47][48][49] Sialadenitis Sialadenitis or inflammation of the salivary gland is a potential consequence of either viral or bacterial infections or results from inflammatory etiology. US is the first-line imaging modality of choice in the evaluation of sialadenitis in the pediatric population.…”