目的 探讨自动选择最佳时相功能结合冠脉运动追踪冻结技术重建血管图像在心率不齐患者心脏冠脉CCTA成像中 的应用。方法 筛选我院行冠脉CCTA检查时出现心律不齐的患者32例，所有患者采用Autogating推荐的时相区间获取单心 动周期的图像数据。根据是否采用运动追踪冻结技术处理图像分为两组：A组，自动选择最佳时相使用STD算法重建图 像；B组，在自动选择最佳时相并使用STD算法重建图像的基础上使用运动追踪冻结技术处理图像。测量主动脉根部的 信噪比SNR并对图像进行主观质量评分，采用两样本配对设计比较的秩和检验比较图像质量。结果 在A组32例患者128 条主血管中，只有3条右冠状动脉不可诊断，其余的均可满足诊断的要求；B组中没有不可诊断血管。A、B两组图像的 信噪比分别为14.45±3.41和14.48±3.43，差异无统计学意义（P=0.677）。A、B两组各主血管的图像质量评分：右冠状 动脉：3.50±0.72和4.09±0.69，P=0.000；左冠状动脉主干：4.03±0.18和4.19±0.40，P=0.083；左回旋支：3.72±0.52和 3.97±0.54，P=0.014；左前降支：3.96±0.35和4.03±0.47，P=0.655。B组中右冠及左回旋支的图像质量较A组显著提高， 左主干和前降支的质量也有所改善。结论 自动选择最佳时相结合冠脉运动追踪冻结技术重建血管在心律不齐患者冠脉CTA 成像中具有可行性，能够重建出满足临床诊断的图像。

Objective To evaluate the effects of the SmartPhase function that automatically selects the optimal cardiac phase for reconstruction combined with a motion correction algorism (named Snap-Shoot Freeze, SSF) on improving image quality in the coronary CT angiography (CCTA) for arrhythmia patients. Methods Data of thirty patients with arrhythmia who underwent CCTA were enrolled. CCTA image raw data was obtained in single cardiac phase and the scanning window was selected based on the recommendation from AutoGating. Images were reconstructed using the cardiac phase recommended by SmartPhase, with the application of SSF (group A) or with SSF (group B). The CT value and noise of the aortic arch root at the level of the left coronary artery were measured and the signal to noise ratio (SNR) was calculated. The main coronary artery scorings were performed independently. The artery image quality scores and SNR from the two groups were analyzed using the rank sum test. Results Three of 120 coronary arteries from group A could not meet the requirements of clinical diagnosis while all coronary arteries from group B could be diagnosed. The SNR of the aortic arch root were not different between the two groups (14.45±3.41 vs. 14.48±3.43, P=0.677). The image quality scores of right coronary artery (RCA), left main coronary artery (LM), left circumflex artery (LCX) and left anterior descending (LAD) from Group A were 3.44±0.75, 4.03±0.19, 3.71±0.52, 3.96±0.3, while the scores for group B were 4.08±0.70, 4.16±0.37, 3.96±0.54, 4.04±0.4. RCA and LCX from Group B were significant higher than that of group A (P=0.000 and P=0.014), while there was no statistically difference between the groups in LM and LAD. SSF can significantly improve RCA and LCX’s image quality. Conclusion SmartPhase combined with SSF in the coronary CT angiography is feasible in patients with arrhythmia and can provide good quality images for clinical diagnosis.