There are well-established imaging criteria allowing imaging-based diagnosis of hepatocellular carcinoma in specific target populations, without the need for pathologic biopsy. Specifically, the combination of arterial phase hyperenhancement and washout are two imaging features yielding high diagnostic specificity for the diagnosis of HCC on multiphasic CT or MRI in the appropriate patient population (e.g., patients with cirrhosis from a nonvascular cause, noncirrhotic HBV, known prior HCC). However, these same imaging criteria can also be seen in benign liver lesions, with reduced specificity for diagnosis of malignancy in non-cirrhotic populations. Thus, it is essential not to use these imaging features for definitive imaging-based diagnosis of malignancy in patients who lack appropriate risk factors because of the risk of inappropriate HCC diagnosis.