双源CT冠状动脉血管成像检查不同心率对心电门控方法选择的影响

目的探讨不同心率选择不同的心电门控,以达到最佳的图像质量和最小的射线剂量。方法对100例不同心率临床怀疑冠心病或冠状动脉早期病变患者进行不同的心电门控扫描,用双源CT冠状动脉成像扫描图像行多平面重组(MPR)、最大密度投影(MIP)、容积再现技术(VRT)重组及Circulation软件分析。将图像质量分为3级,按冠状动脉分段标准评价各个节段的图像质量。结果根据不同心率采用不同的心电门控,尽可能使冠状动脉显示良好的重建方法,用前瞻性心电门控扫描的则直接重建,评价1 000个冠状动脉节段,其中图像质量为1级占73.3%(733/1 000),2级占14.2%(142/1 000),3级者占12.5%(125/1 000);图像质量为2级和3级的节段多由选择了不合适的心电门控方法所致。结论心率在70次以下用前瞻性心电门控图像质量较好,辐射剂量低;心率在70~100次之间用选择性回顾性心电门控(R-R间期70%～80%)方法图像质量较好,辐射剂量超过用前瞻性心电门控方法;心率超过100次最好用回顾性心电门控图像质量较好,但辐射剂量最大,但图像质量好,检查不容易失败。

Influence of different heart rate to the selection of ECG control mode in dual-source CT coronary artery angiography

Objective To explore different ECG control mode of patients with different heart rate by dual-source CT coronary artery angiography based on achieving well coronary artery reconstructive imaging and least X-ray radiate dose. Methods One-hundred patients with coronary artery disease （CAD） or early CAD suspected by clinic underwent dual-source CT coronary artery angiography examination selecting different ECG control mode according to different heart rate levels. All coronary artery imaging reconstruction that included multi-plane reconstruction （MPR）, maximum intensity projection （MIP） and volume rendering technique （VRT） and analysis, were finished at workstation by using Inspace and Circulation software. Imaging quality was classified as 3 grades. Imaging quality of all segments of coronary artery was evaluated according to class standard. Results Appropriate ECG control mode according to different heart rate level was selected based on obtaining good coronary artery reconstructive imaging quality, and that used prospective ECG control mode were directly reconstructed. Imaging quality of one-thousand segments of coronary artery was classified as 733 segments with grade 1 （73.3%）, 142 segments with grade 2 （14.2%） and 125 segments with grade （12.5%）. Segments with grade 2 or 3 imaging quality were more ascribed improper selection of ECG control mode. Conclusion Prospective ECG control mode was ought to selected in patients with low heart rate （〈70 times / min） that owned merits including good imaging quality and low radiate dose. Selective retrospective ECG control mode in R-R interval of 70%-80% was recommend in patients with heart rate between 70 times/min and 100 times/min that possessed good imaging quality but more radiate dose than prospective ECG control mode. And retrospective ECG control mode was chosen in patients with heart rate more than 100 times / min that could obtain good imaging quality and high successful rate, but added radiate dose.