Biliary and reticuloendothelial impairment in hepatocarcinogenesis: the diagnostic role of tissue-specific MR contrast media.

The development and progression of a hepatocellular carcinoma (HCC) in a chronically diseased liver, i.e., the carcinogenesis, comprise a multistep and long-term process. Morphologically, this process is associated with the presence of distinct nodular lesions in the liver that are called 'preneoplastic lesions.' These preneoplastic lesions are associated with and can precede the growth and progression of well-differentiated HCCs . The characterization of nodular lesions and demonstration of the multistep development of HCC in the cirrhotic liver by imaging modalities represent a challenging issue. The arterial hypervascular supply, depicted by different dynamic studies, represents a fundamental radiological criterion for the diagnosis of HCC in cirrhosis. Magnetic resonance (MR) imaging performed with tissue-specific contrast media can help to investigate the "grey area" of carcinogenesis, in which significant histological changes are already present without any imaging evidence of neoangiogenesis. The purpose of this review is to provide information on the properties of tissue-specific MR contrast agents and on their usefulness in the demonstration of the pathologic changes that take place at the level of the biliary and reticuloendothelial systems during the carcinogenetic process in liver cirrhosis.