Localization of Abnormal Parathyroid Tissue With Use of Technetium-99m-Sestamibi

Objective To evaluate the efficacy of “double-phase” technetium-99m-sestamibi scanning in the localization of abnormal parathyroid tissue in patients with hyperparathyroidism. Methods We present a prospective review of patients with hyperparathyroidism seen at a university teaching hospital between June 1994 and May 1997. Twenty-four patients entered into the study underwent preoperative localization with double-phase technetium-99m-sestamibi. The nuclear medicine results were compared with the operative findings. Results The Tc-99m-sestamibi scan correctly identified the location of single parathyroid adenomas in 22 patients (100%). Of the other two patients, both with diffuse parathyroid hyperplasia, one had a negative sestamibi scan and one had only the two inferior parathyroid glands localized on the sestamibi scan. One patient with recurrent hypercalcemia, who previously underwent total parathyroidectomy and parathyroid autotransplantation into the left forearm, had activity localized to that forearm but not to the neck. Subsequently, hyperplastic parathyroid tissue was successfully removed from the transplantation site. Another patient, who had previously undergone two unsuccessful surgical explorations prompted by hyperparathyroidism, had sestamibi localization of an adenoma inferior and medial to the right submandibular gland. The third surgical exploration disclosed a large adenoma medial to the carotid artery, just below the angle of the jaw. In two elderly, debilitated women with positive scans, adenomas were removed with use of local anesthesia. Of 22 patients in whom long-term follow-up was available, 21 remained normocalcemic for a mean period of 11.4 ± 1.7 months postoperatively. One patient in whom hyperplastic parathyroid tissue had been removed from the left forearm had recurrence of hypercalcemia 1 year after operation. Conclusion Technetium-99m-sestamibi scanning is a reliable method for identifying parathyroid adenomas but not as helpful in localizing hyperplastic parathyroid glands. The precise localization of an adenoma simplifies surgical exploration and in selected patients may allow excision of the adenoma under local anesthesia. Tc-99m- sestamibi scanning has become the preferred method for noninvasive localization of abnormal parathyroid glands. (Endocr Pract. 1998;4:184-189)