Variability of Repeated Coronary Artery Calcium Scoring and Radiation Dose on 64- and 16-Slice Computed Tomography by Prospective Electrocardiographically-triggered Axial and Retrospective Electrocardiographically-gated Spiral Computed Tomography

Retrospective ECG-gated 64-slice CT showed the lowest variability. Prospective ECG-triggered 64-slice CT, with low radiation dose, shows low variability on CAC scoring comparable to retrospective ECG-gated 16-slice CT.