Parathyroid and thyroid imaging.

Whether to perform preoperative imaging for parathyroid adenomas is controversial in the "virgin neck" because surgery without imaging is successful in more than 90% of cases. To detect ectopic adenomas or unresected adenomas after failure of initial surgery often requires both a functional study, such as technetium-99m sestamibi nuclear scintigram, and a morphologic study, such as ultrasonography, computed tomography, or magnetic resonance imaging for anatomic landmarks. Most dominant thyroid masses require fine-needle aspiration for diagnosis. Nuclear scintigraphy is useful when the lesion is warm or hot, making a malignancy less likely, but cold lesions are nonspecific. Unless a mass is shown to infiltrate the surrounding soft tissue or spread to lymph nodes, the findings on most cross-sectional imaging studies are also nonspecific.