This document discusses the evaluation of thyroid lesions using sonography. It outlines common thyroid disorders such as enlargement, nodules, hyperthyroidism and hypothyroidism. Imaging approaches like ultrasound, thyroid scintigraphy, CT and MRI are discussed. Sonography can detect masses, cysts, calcifications, tissue texture changes and cervical lymph nodes. Benign lesions like cysts, hematomas, and inflammatory conditions are described. Malignant lesions like papillary carcinoma are also outlined, noting features like ill-defined margins, hypoechogenicity, microcalcifications, hypervascularity and cervical lymph node involvement. Thyroid nodule isotope scans can identify hot or cold nodules.