Motion Artifact Correction by Snapshot Freeze in Coronary CT Angiography at Different Levels of Coronary Enhancement

To investigate the effect of motion correction by SnapShot freeze (SSF) in coronary CT angiography at different levels of enhancement. Sixty-four patients who underwent gemstone coronary CT angiography were divided into two groups by aortic enhancement on the original section of the left coronary artery: group A (n = 30) < 400 HU and group B (n = 34) >= 400 HU. The end-diastolic and end-systolic phases with the least motion were determined for each vessel from a retrospective ECG-gated scan, and reconstructed using a standard algorithm (STD) and SSF. The STD-derived image quality score was 3.5305 +/- 0.5971 in group A and 3.4665 +/- 0.6266 in group B, and the SSF-derived image quality score was 3.6244 +/- 0.5252 in group A and 3.6964 +/- 0.506 in group B. No significant difference was found in STD-derived image quality score between the groups (t = 1.510, P = 0.131), while a significant difference was noted in SSF-derived image quality score between the groups (t = -2.024, P = 0.043). SSF-derived image scores were higher than those from STD in both groups (P < 0.001). STD-derived image quality scores of LAD, LCX, and RCA were lower than those from SSF, and the differences were statistically significant (P < 0.001). SSF can effectively improve the motion artifacts of coronary CT images, especially for RCA, and higher aortic CT enhancement results in greater image quality improvement.