Patients are usually referred because of symptoms (chest pain, dyspnoea on exertion) and/or abnormal or equivocal stress test and/or high cardiovascular risk profile. Exclusion criteria are renal failure (creatinine clearance <60ml/min), known previous reaction to iodinated contrast medium and pregnancy, history of Myocardial Infarction, previous revascularization (PCI and/or CABG).