[Evaluation of clinical utility of 99mTc-MIBI scintigraphy in the localization of hyperfunctioning parathyroid lesions in patients with hyperparathyroidism--a report of multicenter phase III clinical trials]

Phase III clinical study in 78 patients with hyperparathyroidism was performed to determine clinical utility of 99mTc-MIBI in the localization of hyperfunctioning parathyroid lesions. Except slight tremor in one patient, no adverse events were reported. No abnormal changes in clinical laboratories or vital signs were noted. The clinical utility of the agent was evaluated in 70 patients. Out of 108 hyperfunctioning glands, 93 (86%) were detected with 99mTc-MIBI regardless of their histology, numbers, or location. Specifically, single or ectopic lesions were detected with high sensitivity (97% and 100%, respectively). Sensitivity in 53 glands with weight data was 79%, while 94% in 36 glands above 200 mg, which is extremely high compared to the 201T1-99mTc subtraction method. Specificity in a group of PHP patients with single adenoma who underwent surgery was 100% (63/63), though in case of coexistent thyroid disease obviously interfered parathyroid images. Our study indicates that 99mTc-MIBI is a safe and excellent agent for the localization of hyperfunctioning parathyroid tissues. Especially, the fact that 99mTc-MIBI detected ectopic glands with high specificity is a great advantage over the ultrasound or 201Tl-99mTc subtraction method.