IMAGING IN THYROID CANCER

Historically, in addition to clinical examination, the evaluation of thyroid nodules has relied on radionuclide imaging (iodine and technetium), although other imaging methods also have been utilized. For determining the likelihood of malignancy, however, imaging studies have been supplanted by fine-needle aspiration biopsy. Noninvasive imaging studies are most useful in evaluating for metastatic disease. Although less sensitive than thyroglobulin (Tg) in detecting recurrence or metastasis, imaging is perhaps the best method available for determining the actual site of involvement. Imaging studies are thus complementary to Tg measurements, history, and physical examination. This article discusses the major strengths and weaknesses of the noninvasive imaging techniques available to evaluate patients for thyroid malignancy. Circumstances in which a particular technique would be of clinical value are emphasized.