Role of magnetic resonance imaging in hyperparathyroidism.

Magnetic resonance imaging is indicated for the localization of the abnormal gland or glands in patients with recurrent or persistent hyperparathyroidism. The accuracy of MRI is equivalent or superior to thallium subtraction scans and high-resolution ultrasonography for identifying the abnormal glands in the neck and superior to other noninvasive imaging techniques for recognizing ectopic glands in the thorax. Most glands have low to medium intensity on T1-weighted images and high intensity on T2-weighted images; however, glands with unusual signal intensity characteristics occur infrequently. Abnormal glands have shown considerable enhancement on T1-weighted images after use of gadolinium DTPA. Some pitfalls in the identification of abnormal parathyroid glands are now recognized.