Current and future role of noninvasive studies in acute myocardial ischemia and infarction.

During the last 10 years, the pathophysiologic events that follow acute interruption of coronary arterial flow have been extensively worked out. It is now known that the ultimate size of acute myocardial infarction is a function of time after occlusion, size of the arterial territory deprived of arterial blood (area-at-risk), and available collateral flow at the time of occlusion. These concepts are the basis for application of medical therapies, e.g., reperfusion by thrombolysis, which are designed to limit infarct size. Noninvasive imaging aimed at assessing acute myocardial ischemia and infarction is the subject of this review. Potentials and limitations of gamma-radiation single photon emission computed tomography, positron-emission computed tomography, and nuclear magnetic resonance (NMR) spectroscopy are discussed in this review within the context of the known pathophysiology of acute ischemic events.