Pre-contrast HU:
Post-contrast HU (60-75 sec):
Delayed phase HU (15 min):
Absolute washout:
Relative washout:
Caveat: Washout measurements may be the same in adenomas and metastases from hypervascular extraadrenal primary tumors, e.g. renal cell carcinoma (RCC) or hepatocellular carcinoma (HCC).
Caveat: Markedly decreased sensitivity (66.7%) of washout measurements in large adenomas (≥ 3 cm).