Figure 8. Hepatic perfusion index(HPI) map (and corresponding post-contrast T₁ weighted image) from a patient with a large mass occupying much of segments VI–VIII of the right liver. Considerable heterogeneous structure is visible within the mass in the HPI map, including increased HPI around the perimeter. An area of normal-appearing parenchyma is also visible (arrow). Although this area is bright in post-contrast T₁, indicating greater total gadolinium uptake than in the large mass, enhancement occurs mainly during the portal phase, and the corresponding HPI is correctly shown as low.