Thyroid, Parathyroid, Head, and Neck

Palpable thyroid nodules are present in approximately 5–7% of the adult population, and of these, only a small percentage (5–10%) harbor malignancy. Ultrasound (US) imaging of the neck is typically used to characterize thyroid nodules in order to triage lesions with the highest risk of malignancy. Fine needle aspiration (FNA) is recommended for thyroid lesions with radiographically suspicious features (as outlined below). FNA biopsy of the thyroid gland is an increasingly common procedure, with approximately 300,000–500,000 biopsies performed annually in the United States. The 2015 American Thyroid Association management guidelines underscore the importance of radiologic risk stratification.