Evaluation of the thyroid nodule.

The evaluation and management of thyroid nodules remains an area of controversy. The past decade has witnessed two important advances. The increased availability and acceptance of fine-needle aspiration biopsy of thyroid nodules has dramatically altered the clinician's approach to this disease, and provides for the single most precise method for selecting appropriate patients for surgery. The introduction of high-resolution thyroid ultrasonography provides for anatomic definition that is clearly superior to thyroid scintigraphy. However, radionuclide imaging of the thyroid remains critical for determining the functional status of abnormal thyroid tissue. While aspiration, ultrasound, and scintigraphy all have appropriate indications, utility, and limitations, no single test or group of tests substitutes for careful clinical assessment and follow-up. This review attempts to provide a practical approach to the evaluation and management of the thyroid nodule.