Imaging of thyroid disease

1. The mainstay of initial evaluation of possible thyroid disease is ultrasound. There are complex algorithms to help decide whether a thyroid nodule needs to be biopsied, that are determined by things like size, echogenicity, vascularity, margins and shape. NOT all nodules require biopsy!

2. Nodules in the thyroid are often noted on CT initially done for other reasons. When in doubt, ultrasound should be the next study.

3. US cannot reliably detect normal parathyroid glands, as they are very small and inferior or deep in position. US can detect enlarged parathyroid glands or tumors, which are almost always benign and can cause hypercalcemia.

3. Nuclear medicine studies can help in characterizing thyroid and parathyroid abnormalities, both diffuse enlargement and nodules. Nuclear medicine studies must be correlated with TSH levels. In general, 'hot' nodules (those with high uptake on nuclear medicine studies and generally with low TSH) are benign. 'Cold' nodules may require further imaging or biopsy.

4. When determining what to do about thyroid abnormalities, it is important to consider other risk factors like familial history of thyroid cancer, genetic syndromes or prior radiation to the neck or chest.

thyroid nodules