Thyroid computed tomography imaging: pictorial review of variable pathologies

ABSTRACT: Focal and diffuse thyroid abnormalities are commonly encountered during the interpretation of computed tomography (CT) exams performed for various clinical purposes. These findings can often lead to a diagnostic dilemma, as the CT reflects the nonspecific appearances. Ultrasound (US) examination has a superior spatial resolution and is considered the modality of choice for thyroid evaluation. Nevertheless, CT detects incidental thyroid nodules (ITNs) and plays an important role in the evaluation of thyroid cancer. In this pictorial review, we cover a wide spectrum of common and uncommon, incidental and non-incidental thyroid findings from CT scans. We also discuss the most common incidental thyroid findings, best practices for their evaluation, and recommendations for their management. In addition, we explore the role of imaging in the assessment of thyroid carcinoma (before and after treatment) and preoperative thyroid goiter, as well as localization of ectopic and congenital thyroid tissue. TEACHING POINTS: • Thyroid disorders tend to have non-specific CT appearances. • ITNs are common on neck CT. • ITN management depends on nodule size, age, health status, lymphadenopathy, and invasion. • CT is used in assessment of cancer extension, mass effect, invasion, and recurrence. • CT plays a role in preoperative planning in patients with symptomatic goiter.