Detecting Viable Myocardium and Predicting Functional Improvement-Comparisons of Positron Emission Tomography, Rest-Redistribution Thallium-201 Single-Photon Emission Computed Tomography (SPECT), Exercise Thallium-201 Reinjection SPECT, I-123 BMIPP SPECT and Dobutamine Stress Echocardiography- | Synapse