A goiter is an abnormal enlargement of the thyroid gland, which can be diffuse, affecting the entire gland, or nodular, caused by one or more discrete nodules. On ultrasound, the thyroid is measured in three dimensions to calculate its overall volume, and any nodules are individually characterized by their size, shape, echogenicity, margins, and the presence or absence of calcifications. Ultrasound is the primary imaging tool for evaluating goiters because it provides detailed information about the gland’s internal structure that cannot be obtained from physical examination alone. Causes of goiter include iodine deficiency, Hashimoto thyroiditis, Graves disease, and multinodular goiter, each of which has characteristic ultrasound features.
Sonography Term