[Diagnosis of pheochromocytoma using 131I-MIBG scintigraphy].

131I-MIBG scintigraphy was performed on 18 patients with pheochromocytoma and 25 patients with essential hypertension. In comparison of grade of 131I-MIBG accumulation in various organs the heart accumulation of pheochromocytoma group was significantly lower than that of essential hypertension group. And between the positive and false negative accumulation group of pheochromocytoma reverse relationship was observed between the heart and tumor. The results of 131I-MIBG scintigraphy for pheochromocytoma included 78% sensitivity, 100% specificity, and 90% accuracy. False negative accumulation of tumors were shown at 6 lesions in 4 cases. On the bases of CT and operative findings, false negative accumulation was observed not only in very small tumors, but also in large cystic tumors with a small amount of tumor tissue or totally hemorrhagic necrosis within the tumor.