Contrast Media for Liver MRI

Overview: In this lecture, I will provide an overview of the different available gadolinium-based contrast agents, with specific attention on dynamic contrast enhanced imaging and delayed hepatobiliary phase imaging. The dual blood supply of the liver will be reviewed and its importance on understanding the detection and characterization of focal liver lesions. The behavior of the dual blood supply will be exploited with extracellular gadolinium-based contrast agents using rapid dynamic T1-weighted imaging for liver lesion characterization. Further, we will discuss the use of hepatobiliary contrast agents that take up gadolinium into functioning hepatocytes and how this behavior can be exploited on delayed T1-weighed imaging for liver lesion characterization, as well as biliary imaging. The chemical composition, relaxivity, pharmacokinetics of these agents, and how these properties may impact the choice of contrast agent for a particular application, will be discussed. Modifications to imaging protocols that may be helpful for specific contrast agents will be discussed, including strategies for optimization of delayed hepatobiliary imaging. Finally, a set of guidelines currently in use at the University of Wisconsin for choosing between an extracellular contrast agent and a hepatobiliary contrast agent will be provided as a “cheat sheet” to assist users in their chose and dosing of different contrast agents for liver imaging.