Role of magnetic resonance contrast agents in cardiac imaging. Improvements in magnetic resonance imaging (MRI) technology allow adequate spatial and temporal resolution to capture cardiac anatomy and contractile function in exceptional detail and with little risk. However, tissue characterization of the pathophysiologic state of the myocardium may require special indicators or MR contrast agents. These must be tailored for detection by the MRI process, but available agents are effective at low dose and provide a wide range of indicator properties (e.g., myocardial extracellular space, blood pool, capillary permeability and membrane transport). Each agent has a dynamic washin and washout time-intensity curve that may reflect myocardial perfusion or consequences of ischemia. The combined use of MRI and MR contrast agents may provide a single diagnostic examination that fully and quantitatively assesses all indexes of cardiac performance. Such information would be both global and regional, and would be well tolerated by patients. The cost, value and cost-effectiveness of such studies remain speculative. 