PROSPECTIVE COMPARISON OF TECHNETIUM-99M-SESTAMIBI I-123 RADIONUCLIDESCAN VERSUS HIGH-RESOLUTION ULTRASONOGRAPHY FOR THE PREOPERATIVE LOCALIZATION OF ABNORMAL PARATHYROID-GLANDS IN PATIENTS WITH PREVIOUSLY UNOPERATED PRIMARY HYPERPARATHYROIDISM

Surgery for primary hyperparathyroidism is successful in 95% of patien ts, but ectopic glands and anatomic variations in location are causes of surgical failure. The radionuclide imaging agent, technetium (Tc)-9 9m-sestamibi, in conjunction with subtraction iodine-123 scanning, is a new method of preoperative localization of abnormal parathyroid glan ds. In a study approved by the Institutional Review Board, 22 patients with primary hyperparathyroidism underwent preoperative evaluation wi th high-resolution ultrasonography and Tc-99m-sestamibi/I-123 radionuc lide scanning for attempted localization of abnormal parathyroid gland s. Results of Tc-99m-sestamibi scanning and ultrasound were correlated with surgical and pathologic findings. Of 22 patients, 16 had a solit ary parathyroid adenoma, 1 had a double adenoma, and 5 had diffuse par athyroid hyperplasia. The Tc-99m-sestamibi/I-123 radionuclide scan pre operatively identified a solitary adenoma in 14 of 16 patients (sensit ivity: 88%). However, when the data were analyzed retrospectively alon g with surgical and pathologic finding the Tc-99m-sestamibi scan corre ctly localized all parathyroid adenomas for a sensitivity of 100%. The one patient with a double adenoma had a localization image consistent with two enlarged glands. All patients with diffuse parathyroid hyper plasia had Tc-99m-sestamibi imaging consistent with diffuse hyperplasi a, although delineation of individual enlarged glands was not possible . High-resolution ultrasound identified 11 of 16 parathyroid adenomas (sensitivity: 69%). The patient with a double adenoma had a negative u ltrasound. Ultrasound was less accurate in five patients with diffuse hyperplasia: one scan was completely negative, two scans revealed only one enlarged gland, and two scans revealed two enlarged glands. The T c-99m-sestamibi/I-123 subtraction radionuclide scan is more sensitive than high-resolution ultrasonography for the preoperative localization of abnormal parathyroid glands. Tc-99m-sestamibi/I-123 radionuclide s canning may be more useful than ultrasonography to the surgeon in the preoperative localization of abnormal parathyroid glands.