Evaluation The Influence Of Snapshot Freeze Technique On Image Quality Of Coronary CT Angiography:Compared With Multi-sector Reconstruction

Objective:To compare the motion correction algorithm (snapshot freeze, SSF) with on the image quality of coronary CT angiography (CCTA). Methods:60 consecutive Patients were enrolled in the current study.25 patients with suspected coronary heart disease underwent prospectively ECG gated CCTA. All of the CCTA images were reconstructed by both standard (STD) and SSF motion correction.75% R-R interval were used for the reconstruction as the central phase. Image quality and interpretability of STD and SSF reconstructions were compared.35 patients with suspected coronary heart disease underwent retrospective ECG-gate CCTA. Phases of 45% and 75% R-R interval were used as the central phase for the reconstruction respectively, for each phase, three reconstruction modes were compared. CCTA images were interpreted with Liken 4-points score system by two experienced radiologists. The image qualities and interpretability were assessed on per-artery, per-segment and per-patient level. Comparisons of variables were performed with paired Wilcoxon rank sum test and paired Chi-square test. Results:1) For 25 patients (mean age,55.7±10.2 years; male 16, female 9), the mean heart rate was 60.0±7.1 beats/min. SSF reconstructions showed higher interpretability than STD reconstructions on per-segment level [96.3% 341/354) VS 90.7% 321/354), P=0.003], but there were no significant difference on per-patient level、and per-artery level. Image qualities were higher with the use of SSF than STD reconstructions on per-patient level and LAD, LCX and RCA, but similar on LM.2) For 35 patients (mean age,58.3±9.8 years; male 16, female 12), the mean heart rate was 68.3±4.3 beats/min. SSF reconstructions showed higher interpretability than single and double sector STD reconstructions on per-patient level, per-artery leve and per-segment levelof the 45% R-R interval images. But there were no significant difference of the 75% R-R interval images. Image qualities were higher with the use of SSF than single and double sector STD reconstructions on per-patient level of the 45% and 75% R-R interval images. On per-artery level the image qualities were significant difference between SSF, single and double sector STD reconstructions of the 45% R-R interval images on LM, but they were similar on the 75% R-R interval images. There were significant difference on LAD、LCX and RCA in both 45% and 75% R-R interval images. Conclusion:SSF could improve the image quality and interpretability in patients undergoing CCTA. With prospective ECG-gating and retrospective ECG-gating.