Evaluate the efficacy of minimum attenuation value in differentiation of adrenal adenomas from nonadenomas on unenhanced CT.

Most adrenal masses are adenomas which contain a large amount of intracytoplasmic lipid and have lower attenuation values on unenhanced computed tomography (CT) examinations. Mean atrioventricular and CT histogram analysis is commonly used for the diagnosis of adenomas; however, the former disregards tissue heterogeneities of the mass and diagnostic efficiency is decreased, and the latter demands specific post-processing workstation for analyzing the data. The purpose of our study is to develop a simple and sensitive method for the diagnosis of adenomas on unenhanced CT.