Biphasic contrast-enhanced multisection dynamic MR imaging of the liver: potential pitfalls.

Biphasic contrast material-enhanced dynamic magnetic resonance (MR) imaging is an important technique for evaluating liver disease. However, several potential diagnostic pitfalls may be encountered, including lobar, segmental, subsegmental, and subcapsular hyperperfusion abnormalities; early-enhancing pseudolesions, particularly in the medial segment of the left hepatic lobe; heterogeneous hyperperfusion abnormalities throughout the liver; and hypointense pseudolesions due to vascular artifacts, unenhanced hepatic vessels, partial volume artifacts, magnetic susceptibility artifacts, and regenerative nodules in cirrhosis. These abnormalities sometimes have appearances similar to those of true lesions or tumor spread to the surrounding liver parenchyma on arterial-dominant phase dynamic MR images. In most cases, however, no corresponding abnormalities are seen with other pulse sequences or on delayed-phase MR images. In addition, hyperperfusion abnormalities due to readily recognizable causes are often foun...