MRI of pheochromocytoma--comparison with CT, 131I-MIBG, urinary catecholamine level and operative findings]

16 patients (7 male, 9 female) ranging in age from 13 to 71 (44.1 +/- 18.4) years old with clinically diagnosed pheochromocytoma were prospectively evaluated with CT (N = 16), MRI (N = 16), 131I-MIBG (N = 10) and operative findings in order to evaluate their diagnostic efficacy. 1. Normal adrenal glands appeared less intense than the liver on T1-weighted image (T1WI), less intense than or isointense with the liver on both proton density image (PDI) and T2-weighted image (T2WI). 2. Pheochromocytomas with high urinary noradrenaline level appeared less intense than the liver on T1WI, more intense on T2W1 and showed accumulation of radioisotope on 131I-MIBG scintigraphy. In cases with normal urinary noradrenaline level, they appeared less intense than or isointense with the liver on all pulse sequences (T1WI, PDI and T2WI). 3. Although diagnostic accuracy of localization was 81.3% (13/16) by CT, 93.8% (15/16) by MRI and 90% (9/10) by 131I-MIBG scintigraphy, MIBG scintigraphy showed higher diagnostic ability in cases with multiple lesions or recurrent tumors.