Quantitative Measurement of Myocardial Perfusion by Cardiac CT in Patients

It is a common understanding that patients with coronary heart disease are suffering, among others, from reduced myocardial perfusion. In order to increase (normalize) the reduced perfusion, when a conventional approach failed, coronary bypass surgery, coronary vessel dilatation or stenting are performed. The similar situation with reduced myocardial perfusion may be found in patients with stenosis of the aortic valve, where aortic valve replacement may increase myocardial perfusion by left-ventricular remodelling. However, there is presently no method established to measure myocardial perfusion quantitatively and noninvasively before and after a therapeutic intervention. Data of pre- and post-therapeutic myocardial perfusion, quantitatively measured in ml/100g/min would strengthen the indication for specific therapeutic approach and enable an objective control of effectiveness of the applied therapy. Hypothesis: There is a measureable difference in quantitative myocardial perfusion values before (lower) and after (higher) interventional or surgical procedure. The goal of the study is to measure myocardial perfusion by advanced CT technology (e.g. iCT 256 Brilliance ) quantitatively in ml/100g/min in three groups of patients: 1. Before and after coronary bypass surgery 2. Before and after coronary vessel dilatation/stenting 3. Before and after aortic valve replacement. The investigators will not assign specific interventions to the subjects of these three groups. Therefore, the research is strictly observational. Design: Prospective study to measure quantitatively myocardial perfusion in the above mentioned three groups of patients with simultaneous control and registration of all essential, physiological determinants of myocardial perfusion immediately prior to each CT study. The CT myocardial perfusion measurements will be performed directly after the indication for intervention or surgery and on the last day before discharge from hospital. All the collec