Characterization of intrahepatic space-occupying lesions by magnetic resonance imaging.

Hepatic neoplasia can be accurately characterized with magnetic resonance imaging of architectural, signal and dynamic gradient-echo contrast-enhancing features. Architectural characteristics valuable in determining the nature of hepatic neoplasia include the outer and inner contours of the lesion; the presence of fibrous encapsulation; the presence, signal and enhancing characteristics of a central scar; the presence and distribution of hemorrhage or necrosis; the relation of the lesion to regional vasculature and bile ducts; and lesion multiplicity. The signal characteristics in spin-echo and gradient-echo pulse sequences of the adjacent hepatic parenchyma and the lesion itself provide further information. In certain instances hepatic neoplasia can be definitively characterized on dynamic gradient-echo pulse sequences obtained after administration of the contrast agent gadolinium.