The diagnosis of Cushing's syndrome using 131I-19-iodocholesterol uptake and adrenal imaging.

Uptake measurements and visualization of the adrenal glands were performed using 131I-19-iodocholesterol in ten healthy subjects and fourteen patient suffering from Cushing's syndrome (nine hyperplasias and five adenomas). The normal range in healthy subjects (average uptake value +/- 2 SD) is 0.12-0.27% for both adrenals. In patients with Cushing's syndrome the uptake values ranged from 0.321 to 1.497%. Normal bilateral images were obtained in all the healthy subjects as well as in eight of the patients with hyperplasia, whilst the remaining patient with hyperplasia showed distinctly enlarged glands. In contrast, an image of the diseased side only was obtained in patients with adrenal adenomas. We conclude that radiocholesterol studies in Cushing's syndrome allow confirmation of the diagnosis, definition of the pathophysiologic type of disease and lateralization of adrenal adenomas.