Multiple Liver Lesions
Hepatic lesions will enhance at different stages of a multiphase liver CT depending on their vascularity. As a rule of thumb, a HYPERvascular lesion will be hyper-attenuating on the Late Arterial phase. The PV and Delayed phase appearance will depend on how quickly contrast washes out of the lesion. On the other hand, a HYPOvascular lesion will usually be hypo-attenuating on both the Late Arterial and PV phases, because it does not enhance while the rest of the liver does. This patient has both types of lesions, so it is the perfect example to show both at once!
The first lesion in segment 5 has rapid arterial homogeneous enhancement and rapid washout. This most likely represents a Focal Nodule Hyperplasia, but could also be a flash-filling haemangioma.
The second lesion in segment 6 has very minimal enhancement until the delayed phase, which shows progressive centripetal filling. This isn't your typical haemangioma appearance but it can still represent a delayed filling type.