128层螺旋CT冠状动脉血管成像最佳重建时相与心率关系的研究

Research on the Relationship between Heart Rate and Optimal Reconstruction Phase during 128-Slice CT Coronary Angiography

目的：评价患者不同心率、心率波动及不同重建时相的选择，对GE宝石能谱（Discovery CT750 HD）128层螺旋CT冠状动脉血管成像（CTA）图像质量的影响。方法收集我院150例临床疑诊冠心病或冠状动脉粥样硬化的患者，于2012年5月～2013年6月在我院行冠状动脉血管CTA成像检查的影像资料并进行影像后处理，对心动周期的R-R相位30%～95%期间，每间隔5%进行重建。分别进行多平面重组、容积再现、曲面重组、最大密度投影等处理；按扫描时平均心率及心率波动幅度分组，获得最佳重建时相进而评价不同心率及心率波动幅度中的图像质量。结果心率＜70次/min，冠状动脉最佳重建时相为70%～75%R-R间期；心率在75～80次/min，冠状动脉最佳重建时相为75%～85%R-R间期；心率＞85次/min，冠状动脉最佳重建时相为80%～95%R-R间期。图像质量随心率的增加及心率波动幅度的变大而降低，即心率及心率波动幅度与图像质量呈负相关（P〈0.001）。结论合理控制心率、减小心率波动以及选择最佳重建时相可提高图像质量，明显减轻心脏运动伪影，显示较细节段的冠状动脉，对准确诊断冠状动脉病变，具有较高的临床应用价值。

Objective To evaluate the impact of different heart rate, heart rate fluctuations and the reconstruction phase on the image quality of coronary CT with GE Gem Spectroscopy （ Discovery CT750 HD ） 128-slice CT. Methods CTA imaging data of 150 suspected patients with coronary heart disease or coronary atherosclerosis were collected. All of the patients received CTA imaging from May 2012 to June 2013 in our hospital, and the image post-processing was conducted：during the R-R cardiac cycle phase of 30%to 95%, at intervals of 5%, the image reconstruction was conducted. MPR, volume rendering, surface restructuring, maximum intensity projection were conducted retrospectively. The grouping was based on the average heart rate and heart rate lfuctuations. The optimal reconstruction phase was aquired in order to evaluate the images quality under different heart rate and different heart rate lfuctuations. Results When heart rate〈70 beats/min, the best phase of coronary reconstruction was 70%-75%RR interval;and that of 70%-75%RR interval when heart rate was at 75-85 beats/min, 80%-95%RR interval when heart rate〉85 beats/min. The image quality degraded when the heart rate increases and the heart rate lfuctuations become bigger, namely, the heart rate and heart rate lfuctuations were negatively correlated with the image quality （P〈0.001）. Conclusion Reasonable control of the heart rate, reduced heart rate fluctuations and selection of optimal reconstruction phase can improve the image quality, signiifcantly reduce cardiac motion artifacts, and show a more detailed section of the coronary arteries, which has a high clinical value in accurate diagnosis of coronary artery disease.