Investigation useful for detecting extra adrenal phecochromocytoma-
USG
CCT
T2-weighted MRI with gadolinium contrast
MIBG
T2 weighted MRI with gadolinium contrast is optional for detecting pheochromocytoma and is somewhat better than CT for imaging extra adrenal pheochromocytoma and paragangliomas Ref ( Harrison 17 pg 2271)
Endocrinology