Corona enhancements on single level dynamic CTHA (sCTHA) images are thought to be characteristic of hypervascular metastatic liver tumors and HCCs. Herein we present two cases (an FNH and a nodule-in-nodule type HCC) in which sCTHA images showed corona enhancements. In the literature, venous and sinusoidal drainage pathways have been confirmed histopathologically in FNH. We presume that drainage flow occurs mainly through a hepatic venous pathway in FNH and that drainage flow via a sinusoidal pathway is faint and may be visible only when the amount of drainage flow becomes large followed by an increase in tumor size. Moreover, a corona enhancement was also seen in a HCC that lacked a capsule but had a replacing growth pattern. A drainage pathway via a sinusoid may be causing the emergence of a corona enhancement on sCTHA images in the cases discussed herein.
