Multivariable Assessment of Coronary Artery Disease Using Cardiac CT Imaging

The investigators goals are: 1. to develop software for quantitative volumetric analysis of myocardial perfusion from MDCT images 2. to test its ability to accurately determine the presence, location, extend and severity of perfusion abnormalities in agreement with conventional diagnostic techniques (ICA and MPI) in patients with normal and abnormal coronary arteries and/or perfusion patterns 3. to test this approach in patients undergoing vasodilator stress tests with MDCT imaging in combination with the new vasodilator stress agent Regadenoson.