Characterization of adrenal masses that are less than 3cm in diameter can be achieved by calculating its washout on a three-phase CT acquisition (unenhanced, venous, and delayed phase). It does not apply to masses that have a specific appearance such as myelolipoma (fat attenuation). Lesions with attenuation ≤10HU on unenhanced scan are lipid-rich adenomas.
Parameter | Value | |
---|---|---|
Unenhanced attenuation | HU | |
Venous phase attenuation * | HU | |
Delayed phase attenuation * | HU | |
1. Blake MA, Kalra MK, Sweeney AT, Lucey BC, et al. Distinguishing benign from malignant adrenal masses: multi-detector row CT protocol with 10-minute delay. Radiology. 2006;238:578-585.