Background: Technetium 99m-sestamibi imaging might be the best method to localize abnormal parathyroid glands. No studies to date have compared preoperative imaging and intraoperative gamma probe localization in patients with primary hyperparathyroidism.
Study design: This prospective study included 20 arbitrarily selected patients with primary hyperparathyroidism, verified by elevated serum ionized calcium and intact parathyroid hormone concentrations and low serum phosphatase level. Each patient underwent both preoperative imaging study of the parathyroid glands with technetium 99m-sestamibi (dose 740MBq) and intraoperative localization with a handheld gamma probe. Full collar exploration served as the gold standard.
Results: Hypercalcemia and hypophosphatemia normalized in each patient. A single parathyroid adenoma was confirmed histologically in 16 and hyperplasia (4 abnormal glands) in 4 patients. None of the patients had multiple adenomas. The sensitivity of the preoperative scan was 81% (13 of 16 patients) in adenoma patients and 100% (4 of 4 patients) in hyperplasia. The corresponding specificity was 88% and 100%. Intraoperatively only 8 of 16 adenomas were correctly detected (sensitivity 50%), and none of the hyperplastic glands were correctly detected.
Conclusions: In unselected patients with primary hyperparathyroidism, preoperative technetium 99m-sestamibi imaging is more accurate than intraoperative gamma probe detection in localizing abnormal parathyroid glands.