Obtain a better understanding of the clinical utility of advanced non-isotope-based imaging modalities to detect relevant CAD as potential alternatives to SPECT. Approximately 450 subjects will be enrolled in total. Three groups of about 150 patients per group. Each group will undergo imaging with 2 modalities; Group 1: 99mTcSPECT plus CMR, Group 2: 99mTcSPECT plus CT, Group 3:99mTcSPECT plus stress echocardiography. All 450 patients will undergo standard invasive coronary angiography following completion of non-invasive imaging, except for patients in whom both nuclear and non-nuclear imaging modalities reveal a normal result confirming the absence of significant coronary artery disease (i.e invasive angiography would not be clinically indicated and FFR would be considered to be above 0.8). Thrombolysis in Myocardial Infraction (TIMI) flow will be measured in all patients undergoing angiography, and fractional flow reserve (FFR) will be measured in all patients except those with TIMI flow =0, 1 and 2. All imaging procedures must be completed within 6 weeks. All patients will have a follow-up visit at 6 months after enrollment. During the 6 month follow-up visit major adverse cardiovascular events will be collected and adjudicated by a clinical endpoint committee (CEC).