Localization of functioning pheochromocytomas by venous sampling and radioenzymatic analysis

The authors describe a sensitive radioenzymatic technique for determining blood catecholamines which is very effective in localizing occult functioning pheochromocytomas. It appears to be more consistent than any other technique in demonstrating theirapproximate location. Combined with other noninvasive studies such as CT, it should greatly facilitate demonstration of extra-adrenal pheochromocytomas, thereby reducing the need for more invasive procedures such as arteriography.