Location of aldosterone-producing adenomas with 131I-19-iodocholesterol

We used 131I-19-iodocholesterol as an adrenal-imaging agent in 27 hypertensive patients who had biochemical evidence of abnormalities in the renin-angiotensin-aldosterone system. In 10 of 12 patients in whom the biochemical findings suggested the presence of an aldosterone-producing adenoma the adrenal uptake was asymmetric. The adenoma was subsequently confirmed in all eight patients in this group who underwent operation. In contrast, the adrenal uptake was asymmetric in only one of 13 patients with biochemical evidence of iodopathic hyperaldosteronism or low-renin essential hypertension. Two patients with adrenal carcinoma causing primary aldosteronism did not concentrate the isotope in their tumors. When metabolic studies suggest an aldosterone-producing adenoma, adrenal imaging with 131I-19-iodocholesterol may locate the tumor before operation.