双源CT冠状动脉成像的初步研究

Coronary artery imaging with dual-source CT:initial experience

目的初步探讨无需口服控制心率药物准备的双源 CT 冠状动脉成像的扫描技术和图像质量。方法对215例临床怀疑冠心病或冠状动脉早期病变患者进行无需口服控制心率药物准备的双源 CT 冠状动脉成像。扫描步骤包括平扫和增强扫描。用平扫图像行冠状动脉钙化积分,用增强扫描图像行多平面重组(MPR)、最大密度投影(MIP)及容积再现技术(VRT)重组。总结双源 CT冠状动脉成像的扫描技术和后处理方法。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 215例患者钙化积分值中位数为82.2(2.3～1827.9)。增强扫描平均心率为(80.6±15.3)(57～139)次/min,尽可能使冠状动脉良好显示的后处理方法有:(1)多个时相筛选法;(2)2个或多个时相补充法;(3)早搏去除法和心律不齐移位法。共评价3026个冠状动脉节段,其中图像质量为1级者占97.5%(2951/3026),2级者占2.0%(62/3026),为3级者占0.5%(13/3026);图像质量为2级和3级的节段多由于呼吸伪影所致。215例患者共91例冠状动脉各节段均未见斑块或狭窄,共诊断<50%冠状动脉狭窄节段112个,≥50%冠状动脉狭窄节段213个。结论双源 CT 冠状动脉成像在无需口服控制心率药物准备的情况下可获得非常好的冠状动脉各节段图像,心率不再是影响图像质量的关键因素,通过单时相或多时相重组可良好显示冠状动脉主干及分支。

Objective To explore the scan technique and image quality of coronary artery imaging with dual-source CT without oral Betaloc preparation. Methods Plain and enhanced dual-source CT coronary artery imaging without oral Betaloc preparation was performed in 215 patients with clinically suspected coronary heart disease or early-stage coronary lesions. Calcium scoring with plain scan images and multi-planar reconstruction （MPR）, maximum intensity projection （MIP） and volume rendering technique （VRT） reconstruction with enhanced scan images were made in all cases. The scan technique and post reconstruction experience was summarized. The image quality was classified as three grades, and coronary segments classified according to AHA standards were evaluated. Results The median of calcium score of the 215 cases was 82.2 （2.3-1827.9）. The average heart rate of the enhanced scan was （ 80. 6± 15.3 ） （57-139） bpm. The post reconstruction methods with which coronary segments could be shown as best as possible consisted of （1）muhiphases screening methods, （2） bi-phase or multiple-phase complement method, and （3） premature beat removing or arrhythmia shifting method. Altogether 3026 coronary segments were evaluated, among them 97. 5% were evaluated as grade 1 image quality, 2.0% were evaluated as grade 2 and 0. 5% were evaluated as grade 3. The coronary segments in 91 cases were completely normal, while 112 segments with 〈 50% stenosis and 213 segments with 〉t 50% stenosis were diagnosed. Conclusion Excellent coronary artery image could be obtained with dual-source CT without oral Betaloc preparation. Heart rate was not a major source of the artifact, and coronary segments could be well shown with single or multiple-phase reconstruction method.