冠状动脉CT成像中冠状动脉追踪冻结技术的价值

Influence of Snapshot Freeze Motion Correction Algorithm on Image Quality of Coronary CT Angiography

目的：探讨不同心率条件下应用冠状动脉追踪冻结技术（SSF）对冠脉CT血管成像运动伪影的改善效果。方法：连续收集了113例疑诊冠心病患者,使用Discovery CT 750 HD Freedom行冠脉CTA检查,图像均采用标准算法（STD）及SSF算法两种方法进行重建,由两位主治以上医师以Likert 4分作为评分标准,采用随机双盲法对冠状动脉分支及节段水平的图像质量进行独立判读。以扫描时心率为标准,分为1-6组,相同心率组不同重建方法的图像质量评分比较采用秩和检验,可判读性比较采用卡方检验。结果：所有心率组SSF算法重建图像质量在前降支、回旋支、右冠状动脉每支血管水平评分均明显高于STD（P均〈0.05）;左主干两种算法图像评分差异无统计学意义（P均〉0.05）,节段评分SSF算法显著高于STD算法（P均〈0.001）。3-6组SSF算法重建图像可判读性在节段水平均明显高于STD重建图像（P均〈0.01）;1-2组两种算法可判读性差异无统计学意义;4-5组SSF算法重建图像可判读性在右冠状动脉每支血管水平明显高于STD重建图像（P均〈0.01）。结论：与标准算法比较,SSF能够明显改善各心率组图像质量,并明显提高了高心率组图像的可判读性。

Purpose：This study aimed to investigate the effect of snapshot freeze（SSF） motion correction algorithm on the motion artifact of coronary CT angiography（CCTA） in patients with different heart rates（HR）. Methods：One hundred and thirteen patients with suspected coronary heart disease were undergone CCTA on Discovery CT 750 HD Freedom. Standard（STD） and SSF motion correction were performed for each patient, 2 experienced readers independently graded image qualities using a 4-point Likert scale. The image quality scores were assessed on per-artery and per-segment level, patients were assigned to 6 different groups based on their average HR during coronary CTA. Comparisons of image quality were performed with Wilcoxon signed-rank tests, and comparisons of percentages of interpretable image quality were performed using Fisher＇s exact tests. Results： The image quality scores were higher with the use of SSF than that with STD（P〈0.05） on left anterior descending（LAD）, left circumflex（LCX） and right coronary artery（RCA） in both groups. There was no statistical significant difference for left main coronary artery（P〉0.05）. Images acquired with SSF showed higher image scores than that with STD on per-segment level（P〈0.001）. Images acquired with SSF showed higher interpretability than that with STD on per-artery level（P〈0.01） in group 3-6, but not for group of 1-2. The per-artery interpretability was significantly higher using SSF in RCA（P〈0.01） in group 4-6. Conclusion： The SSF motion correction algorithm reconstruction provided the same or even better image quality andinterpretability in both groups, it may be more beneficial to the patients with a higher HR.