Influence of heart rate and phase of the cardiac cycle on the occurrence of motion artifact in dual-source CT angiography of the coronary arteries

BackgroundCoronary CT angiography allows visualization of the coronary arteries. However, motion artifact can impair delineation of the coronary artery lumen and detection of coronary artery stenoses.ObjectiveWe investigated the influence of heart rate and the segment of the cardiac cycle during which images are reconstructed on the occurrence of motion artifacts.MethodsWe evaluated coronary CT angiography datasets obtained by 64-slice dual-source CT in 100 consecutive patients. Data were reconstructed at 13 time instants during the cardiac cycle and evaluated for the presence of motion artifact.ResultsMean heart rate was 66±14 beats/min. Overall, 98 of 100 patients had evaluable datasets. For heart rates ≤60 beats/min, optimal image quality was uniformly found during late diastole (100% of cases with evaluable image quality during a time window between 65% and 75% of the cardiac cycle). With increasing heart rates, images reconstructed during late systole more frequently provided best image quality. However, image reconstruction could not be restricted to a systolic time period. To achieve evaluable image quality in 95% of cases, data acquired between 25% and 75% of the cardiac cycle had to be available for patients with heart rates >60 beats/min.ConclusionDual-source CT provides high image quality across a wide range of heart rates. Although data acquisition may be limited to diastole for patients with heart rates ≤60 beats/min, the availability of data acquired both during systole and diastole is necessary for patients with higher heart rates.