[en] The project involves the development of a quantitative dual radionuclide imaging approach for defining regions of infarction, ischemia, and scar. Studies proceeded in a parallel fashion in both animal and patient laboratories. The authors have defined the pathophysiologic correlates of dual radionuclide myocardial uptake. Pharmacologic modification of nuclide uptake has been demonstrated. Infarction has been quantified with both radionuclides in the experimental animal and have related these measurements to pathologically determined infarct weight. In addition, an alternative flow independent myocardial necrosis model has been developed and investigated with radionuclides. The feasibility and utility of dual radionuclide imaging of acute infarction in man has been demonstrated. Additional radionuclide techniques for assessing ventricular function and wall motion in the setting of infarction have been developed