The Investigators and others have demonstrated direct imaging of myocardial ischemia using 18F-Fluorodeoxyglucose (18FDG) with exercise or dipyridamole stress and positron emission tomography (PET) or single photon emission computed tomography (SPECT). This approach with "hot-spot" imaging may have greater diagnostic accuracy for ischemia than conventional "cold-spot" myocardial perfusion imaging.