Patients will undergo a coronary calcium score (CTCAC) and CT coronary angiography scan on a 256-slice CT scanner (Philips Brilliance iCT, Philips Healthcare, Best, the Netherlands). Prospective ECG-gating (Step & Shoot Cardiac, Philips Healthcare, Best, The Netherlands) at 75 % of the R-R interval will be performed in order to minimize radiation burden.