Contrast agents used in MR imaging of the liver.

Several categories of contrast agents with different biodistributions are currently available for magnetic resonance imaging of the liver. They improve lesion detection and characterization by increasing lesion-liver contrast. These agents include nonspecific extracellular gadolinium chelates, reticuloendothelial system- specific iron oxides, hepatocyte-selective agents, and combined perfusion and hepatocyte-selective agents. This article describes the currently used contrast agents in magnetic resonance imaging of the liver, summarizes their mechanisms of action, biodistributions, and safety profiles. Additionally, it reviews their main clinical indications, administration and imaging techniques, and the appearances of common hepatic lesions in contrast-enhanced studies.