Value of computed tomography of the abdomen and chest in investigation of Cushing's syndrome.

Computed tomography (CT) scans were performed on 37 patients with biochemically proved Cushing's syndrome to evaluate the role of CT in the investigation of this condition. CT rapidly and correctly identified all 15 adrenocortical tumours, distinguishing five carcinomas from the 10 adenomas. In ACTH-dependent Cushing's syndrome appreciable bilateral adrenal enlargement was common in patients with an ectopic source (6 of 10 cases), while those with a pituitary source usually had normal sized adrenals (9 of 10). Two patients with a history of over seven years had bilateral adrenal nodules. CT was more accurate in locating a primary ectopic source of ACTH (5 of 12 cases) than any other technique and was particularly valuable in detecting small (less than 1.5 cm) peripheral lung carcinoid tumours which may be undetectable by conventional x-ray techniques. Its speed, accuracy, and simplicity make CT the technique of choice both to show the adrenal anatomy and to locate a suspected ectopic ACTH-secreting tumour in patients with proved Cushing's syndrome.