MR EVALUATION OF MYOCARDIAL-ISCHEMIA AND INFARCTION

Magnetic resonance (MR) imaging is potentially a well-suited modality to guide clinical management of patients with myocardial ischemia and infarction. Evaluation of regional perfusion and contractile function distinguishes between normal and ischemic myocardium and identifies ar eas of infarction, stunning, and hibernation. Recent technical improve ments in MR perfusion imaging include the use of echoplanar and fast g radient-echo sequences to capture the first pass of MR contrast agents through the myocardium. Evaluation of regional function will likely b enefit from motion-encoded MR imaging, which employs tissue tagging or cine phase-contrast to track the myocardial motion throughout the car diac cycle. Stress imaging with dobutamine and dipyridamole will furth er enhance the accuracy of MR myocardial imaging. Advantages of MR ima ging over other available noninvasive modalities include its good spat ial resolution and the potential for three-dimensional imaging without the need for geometric assumptions. Importantly, a single comprehensi ve MR examination can assess not only regional myocardial perfusion an d function, but in addition also global ventricular size and function and (perhaps) coronary artery anatomy and flow. Such integrated cardia c evaluation may turn out to be a cost-effective strategy. Large clini cal trials incorporating outcome analysis are now needed to see whethe r cardiac MR imaging can live up to the current high expectations.