Prediction of adrenal adenomas with hypercortisolism by using adrenal computed tomography: Emphasis on contralateral adrenal thinning

Purpose: To analyze computed tomography (CT) characteristics of adrenal adenomas with hypercortisolism on adrenal CT compared to adenomas with hyperaldosteronism. Materials and Methods: Thirty-two adrenal adenomas, consisting of group A (hypercortisolism, n = 16) and group B (hyperaldosteronism, n = 16), were evaluated with adrenal CT. Thirty-four patients without adrenal nodule on CT and hormonal abnormality (group C) were selected for comparison. In adenomas, lesion size, attenuation value, and absolute and relative washout were compared between groups A and B. The mean adrenal thickness was compared quantitatively and qualitatively between groups. Results: All of adenomas satisfied absolute (≥60%) or relative (≥40%) washout criteria of adrenal CT. The mean adrenal thickness was 1.6 ± 0.3 mm in group A, 2.9 ± 0.5 mm in group B, and 3.0 ± 0.4 mm in group C (group Aversus B or C, P < 0.001; group B versus C, P = 0.775). For differentiating group A from B, the area under the curve of quantitative and qualitative analyses for contralateral adrenal thickness was 0.982 and 0.934, respectively. Both sensitivity and specificity with cutoff of 2.0 mm or less in thickness and probably thin or more in visual score were 93.7% and 93.7%, and 87.5% and 93.7%, respectively, for predicting group A. Conclusions: Contralateral adrenal thinning on CT helps predict adrenal adenomas with hypercortisolism.