We assessed the usefulness and reliability of computed tomography (CT scan) in evaluating adrenal hyperplasia in 38 patients, including 14 with Cushing's disease, 17 with idiopathic hyperaldosteronism (IHA), and 7 with the adrenogenital syndrome (AGS). Eighty-two normal subjects were also examined. We analyzed the shape of the adrenal gland and quantitated its thickness, width and length. Visual inspection revealed V-shaped right adrenal glands in 100% of patients with Cushing's disease, 94% of

more »

... patients with IHA,100% of patients with AGS and in 41% of the normal subjects. Triangular left adrenal glands were observed in 100% of patients with Cushing's disease, 82% of patients with IHA, 67% of patients with AGS and in 12% of the normal subjects. Quantitative analysis showed that the right adrenal gland was significantly thicker and longer in patients with Cushing's disease, IHA and in those with AGS than in normal subjects. The right adrenal gland was significantly wider in the patients with Cushing's disease and AGS than in control subjects. The left adrenal gland was significantly wider and longer in patients with Cushing's disease and AGS than in the normal controls. Analysis of individual data indicated that the upper limit of normal for thickness of the right adrenal was 7 mm. Therefore, adrenal hyperplasia was strongly suggested when the right adrenal gland was more than 7 mm thick. Our findings suggest that the CT scan is useful and reliable in diagnosing adrenal hyperplasia.