The efficacy of technetium-99m-MIBI scan and intraoperative methylene blue staining for the localization of abnormal parathyroid glands

The efficacy of the technetium-99m-2-methoxy-isobutylisonitrile (Tc-MIBI) scan and intraoperative methylene blue staining was analyzed in a consecutive series of 15 patients with primary hyperparathyroidism who underwent neck surgical exploration. A total of 17 abnormal parathyroid glands were removed, 7 of which were confirmed histologically as adenomas and 10 as hyperplasias. The Tc-MIBI scan and the thallium-201-technetium-99m subtraction (TI/Tc) scan preoperatively localized 11 (69%) of 16, and 6 (40%) of 15 abnormal parathyroid glands, respectively. The Tc-MIBI scan correctly localized two ectopic abnormal parathyroid glands which were not localized by the Tl/Tc scan or ultrasonography (US). However, it also demonstrated falsepositive accumulations caused by thyroid diseases in two patients. There were 4 abnormal parathyroid glands not detected by the preoperative imaging techniques, whereas all 17 abnormal parathyroid glands were stained with methylene blue, the infusion of which caused no adverse effects or toxicity. In conclusion, Tc-MIBI scanning and intraoperative methylene blue staining are effective techniques for the localization of abnormal parathyroid glands in patients with primary hyperparathyroidism.