Role of ultrasonography in thyroid disease.

Ultrasonography (US) is the single-most valuable imaging modality in the evaluation of the thyroid gland. This review discusses the US appearances of thyroid nodules, emphasizing sonographic features associated with potentially malignant or, at the other end of the spectrum, likely benign nodules. Diffuse thyroid abnormalities have also been reviewed. The technique of ultrasound-guided fine-needle aspiration biopsy and the emerging role of elastography in characterizing thyroid nodules have also been addressed.