Advances in Functional and Molecular MRI Technologies in Chronic Liver Diseases.
MRI has emerged as the most comprehensive noninvasive diagnostic tool for liver diseases. In recent years, the value of MRI in the liver has been significantly enhanced by a wide range of contrast agents, both clinically available and under development, that add functional information to the anatomically detailed morphological images, or increase the distinction between normal and pathological tissues by targeting molecular and cellular events. Several classes of contrast agents are available for contrast-enhanced hepatic MRI, including 1) conventional nonspecific extracellular fluid (ECF) contrast agents for assessing tissue perfusion; 2) hepatobiliary-specific contrast agents that are taken up by functioning hepatocytes and excreted through the biliary system for evaluating hepatobiliary function; 3) Superparamagnetic iron oxide particles that accumulate in Kuppfer cells; and 4) novel molecular contrast agents that are biochemically targeted to specific molecular/cellular processes for staging liver diseases or detecting treatment responses. The use of different functional and molecular MRI methods allows noninvasive assessment of disease burden, progression, and treatment response in a variety of liver diseases. The multiparametric capability of MR imaging provides the opportunity for high diagnostic performance by combining imaging biomarkers.