CT appearance of the adrenal glands in adrenocorticotrophic hormone-dependent Cushing's syndrome

OBJECTIVE. The purpose of this study was to describe the size and appearance of the adrenal glands on CT in patients with adrenocorticotrophic hormone (ACTH)-dependent Cushing's syndrome and to correlate gland dimensions with circulating cortisol and ACTH levels. MATERIALS AND METHODS. We retrospectively analyzed clinical, biochemical, and imaging data for 53 patients referred for CT of the adrenals as part of an investigation for ACTH-dependent Cushing's syndrome at our institution between 1988 and 1997. Two observers, who were unaware of the endocrine data, measured the body and limb widths of the adrenal glands using an electronic cursor. RESULTS. Of the 53 patients, 37 (70%) were shown to have enlarged adrenal glands on CT. The mean width of the adrenal limbs positively correlated with the circulating cortisol and ACTH levels. The adrenals were larger in patients with ectopic ACTH syndrome than in patients with Cushing's disease (p < .02). Ten patients (19%) had nodules that were 10 mm or greater in diameter. CONCLUSION. The adrenal glands were often enlarged in patients with ACTH-dependent Cushing's syndrome, and the enlargement could be quantified on CT. However, having normal-sized adrenals (observed in 30% the patients in our study) did not preclude such a diagnosis. We found that adrenal limb width positively correlates with ACTH and cortisol levels.