Figure 5d.

Dynamic enhancement patterns in fibrous versus neoplastic tissue after administration of a gadolinium-based contrast agent. Axial 3D T1-weighted spoiled gradient-echo images (~4/1.5, flip angle = 15°) of the cirrhotic liver, obtained at 3 T before (a) and 20 seconds (b), 80 seconds (c), and 5 minutes (d) after intravenous injection of a gadolinium-based contrast agent, show fibrotic reticulations in the liver parenchyma. The reticulations enhance progressively after contrast agent administration. Although some of the reticulations are enhanced at the arterial phase, most are not enhanced until the more delayed images (black arrows in c and d). A 2.0 × 1.8-cm exophytic HCC (*) arises from segment 6. A fibrous capsule (white arrow in c and d) surrounds the tumor. The fibrous capsule enhances progressively, with a temporal pattern similar to that of the parenchymal fibrotic reticulations. By comparison, the HCC enhances vividly on the arterial phase image, then washes out to hypointensity relative to the fibrotic reticulations on the venous phase images.