 Cardiac CT analysis. Selected participants will undergo CT angiography for the evaluation and quantification of CAD using a 256-slice system Brilliance iCT, Philips Healthcare, Cleveland, Ohio. Data will be acquired with a collimation of 96 X 0.625 mm and a gantry rotation time of 330 ms. Intravenous injection of 60 to 90 ml of nonionic contrast agent at a flow rate of 5 mls will be followed by a 30-ml saline chase bolus 3 mls. Acquisition will be performed during an inspiratory breath hold while the electrocardiogram will be recorded simultaneously to allow, dependent from the heart rate, retrospective or prospective gating of the data. All images will be reconstructed with a slice thickness of 0.67 mm and a slice increment of 0.34 mm. The complete dataset will be transmitted to a dedicated CT workstation with a 3-dimensional reconstruction tool specifically designed for coronary angiography Philips Intellispace Portal, version 7.0 to allow for multiplanar reformations and quantitative plaque analysis. An independent reader will review all studies. Each vessel containing significant stenosis will be analyzed in curved multiplanar reformatted images in long-axis and cross-sectional views. Diameters at the site of maximum stenosis and at proximal and distal references will be measured. Degree of stenosis will be calculated as the ratio of the difference between the diameter at maximum stenosis and the mean of diameters at the proximal and distal references divided by the mean of diameters at proximal and distal references and expressed as percentage. Remodeling index will be calculated as the outer vessel area at the site of maximum stenosis divided by the mean of outer vessel areas at proximal and distal references. Positive remodeling will be defined as a remodeling index 1.05. Plaque volume will be automatically calculated as the volume of all voxels segmented between the luminal and outer vessel boundaries on curved multiplanar reformatted images. Proximal and distal references will be used as the proximal and distal ends of the plaques. The investigators will report the total volume of plaque and volumes of plaque subtypes: calcified, non-calcified, and mixed plaques. 