<prompt> Which one of the following is not a CT feature of Adrenal adenoma?Low attenuationHomogeneous density and well defined bordersEnhances rapidly, contrast stays in it for relatively longer time and washes out lateCalcification is rare  <response>: Enhances rapidly, contrast stays in it for relatively longer time and washes out late Adrenal adenomas show rapid contrast enhancement and rapid subsequent washout; whereas nonadenomas adrenal ca, mets and pheochromocytomas show slower washout. Characterstics of adenomas which help differentiate it from nonadenomas Homogenous well defined rounded tumor; usually smaller than 4 cm Low attenuation on CT Signal loss on MR chemical shift imaging Contrast enhancement pattern adenomas show rapid enhancement and rapid washout whereas nonadenomas show delayed washout Findings so malignancy in an incidentally discovered adrenal mass Harrison 17e p2258 - large size 4 cm - tumor inhomogenesity and irregular margins - calcifications - high attenuation of CT - no loss of signal on Chemical shift MR 