Computed tomography and 131I-MIBG scintigraphy in the diagnosis of pheochromocytoma

In order to evaluate the usefulness of computed tomography (CT) and 131I meta-iodobenzylguanidine (131I-MIBG) scintigraphy for the localization of pheochromocytoma, a prospective study was undertaken in 23 patients with possible pheochromocytoma. Seventeen tumors were identified in 13 patients. Two tumors were extra-adrenal. CT was superior for locating tumors in the adrenal glands while 131I-MIBG scintigraphy was more useful in the detection of extra-adrenal pheochromocytoma. Together with adrenal and extra-adrenal pheochromocytoma, the sensitivity for locating the tumor was calculated as 82 per cent (14/17) for CT and 76 per cent (13/17) for 131I-MIBG scintigraphy, respectively. One adrenal tumor (1 cm in size) only was missed by both methods. No false positive CT scans of 131I-MIBG scintigraphy were obtained in the remaining 10 patients who had possible pheochromocytoma but were excluded. These results indicated that CT and 131I-MIBG scintigraphy were both useful tools for detecting pheochromocytoma.