Localization of abnormal parathyroid glands with jugular sampling for parathyroid hormone, and subtraction scanning with sestamibi or tetrofosmine.

Background: Accurate pre-operative localization of abnormal parathyroid glands is an essential prerequisite for elective surgical approaches such as the unilateral approach for treatment of primary hyperparathyroidism.

Methods: In 175 patients undergoing a bilateral neck exploration for primary hyperparathyroidism, localization of abnormal parathyroid glands was performed with jugular venous sampling for parathyroid hormone (PTH, n = 75), subtraction scan with iodine 123 and technetium-99m-sestamibi (MIBI, n = 50), or tetrofosmine (TTF, n = 50). The results of these localization studies were compared with operative findings.

Results: The sensitivity of PTH, MIBI, and TTF was 41, 63, and 71%, respectively. The specificity was 90, 98, and 98% and the positive predictive value was 85%, 82%, and 87%, respectively. The smallest abnormal parathyroid that was correctly detected weighed 110 mg with PTH, 118 mg with MIBI, and 70 mg with TTF. Subtraction scan (MIBI and TTF) detected mediastinal glands in five cases out of six. In patients with multiglandular disease, the results of all three studies were severely impaired.

Conclusions: Subtraction scanning with MIBI or TTF, but not jugular sampling for PTH, appeared to be useful for localization of abnormal parathyroid glands in patients with primary hyperparathyroidism. Nevertheless, an elective unilateral approach guided by the localization studies would not have allowed the excision of all abnormal parathyroid glands in patients with multiglandular disease.