CTCA data analysis - Coronary Artery Atherosclerotic plaque assessment All CTCA angiograms are evaluated locally by 2 experienced board certified observers. In case of disagreement, a joint reading was performed and a consensus was reached. Coronary arteries were divided into 15-16 segments according to the modified American Heart Association classification and in the case the intermediate branch was present it was added to the classification. All coronary segments were considered in the analysis. First, each segment was classified as assessable or not assessable. All assessable segments were then evaluated for the presence of any atherosclerotic plaque. Axial images and curved multiplanar reconstructions of the segmental vasculature were utilized for the assessment. Coronary plaques were defined as described previously as structures of >1mm^2 within and/or adjacent to the coronary artery lumen which are clearly distinguishable from the vessel lumen and surrounding pericardial tissue. Obstructive coronary plaques were defined as plaques resulting in ≥50% luminal narrowing; non obstructive plaques were defined as plaques that resulted in <50% luminal narrowing. Patients were classified as belonging to one of three groups based on the CTCA findings: 1) patients with normal coronary arteries, 2) patients with non obstructive coronary artery disease, and 3) patients with obstructive coronary artery disease (presence of at least one plaque ≥50%).