Cross-sectional imaging work-up of adrenal masses

Figure 2 A patient presents with an indeterminate left adrenal nodule (arrows) on computed tomography. Non-contrast (A), arterial phase (B) and 15 min delayed (C) images of through the left adrenal gland demonstrate Hounsfield Units values of 19, 164 and 48, respectively. Absolute contrast enhancement wash-out (ACEW) percentage and the relative contrast enhancement wash-out (RCEW) percentage were calculated. The ACEW was [(164 - 48)/(164 - 19)] × 100 = 80%, which is greater than 60% and consistent with an adenoma. The RCEW was [(164 - 48)/164] × 100 = 70.7%, which is greater than 40% and also consistent with an adenoma.