Contrast Enhanced Mri of the Liver State-of-the-art

A variety of different categories of liver contrast agents, and within each category, a number of individual agents, are currently available for clinical use. This review describes the use of non-specific extracellular gadolinium chelates, reticulo-endothelial system specific iron oxide particulate agents, hepatocyteselective, and combined perfusional hepatocyte-selective agents. The greatest clinical experience is with non-specific extracellular gadolinium chelates. The relatively low cost, safety, good patient tolerance, and ability to detect and characterize a wide range of liver diseases has rendered it a very commonly employed agent. Reticulo-endothelial system agents improve lesion detection by decreasing the signal intensity of background liver on T2-weighted images rendering focal hepatic lesions with negligible reticuloendothelial cells, for example metastases, more conspicous. Hepatocyte selective contrast agents increase the signal intensity of background liver on T1-weighted images rendering non hepatocyte containing focal lesions, for example metastases, more conspicious. This review describes the different categories of contrast agents, techniques for their administration, sequences to be employed, and appearances of common entities on contrast enhanced studies.