前瞻性门控技术在双源CT冠状动脉成像中的应用

摘要

Objective To evaluate the effect of prospective ECG -gated scanning in decreasing X-ray dose and its CT applied value in coronary angiography application value. Methods Using dual-source 64 row CT,50 patients with heart rate less than 70 times per minute and breath-holding good underwent prospective ECG -gated low doses of coronary CT scans (group A) ,50 cases with heart rates less than 70 times per minute(group B) and more than 70 times per minute( group C) underwent retrospective ECG -gated coronary CT scanning. The coronary CT image quality and the difference of radiation dose were calculated and analysed in all cases. Results The image quality using both prospective ECG -gated and retrospective ECG -gated scans is of no obvious difference between three groups. The score of image quality more than 3 scores in prospective ECG -gated mode was up to 98% , image quality in all cases was satisfactory. The dose length product and total effective dose were not difference statistically between two scan modes(P＜0. 001). The total effective doses in prospective ECG -gated scan were decreased for 75. 15% and 79. 56% in group A , B and C,respectively. Conclusion The prospective ECG -gated coronary CT scan can be applied as conventional technology, and can greatly reduce CT coronary angiography radiation dose.%目的 评价前瞻性门控扫描技术减低X线辐射的效能及前瞻性门控低剂量扫描冠状动脉CT成像技术的应用价值.方法 通过使用双源64排CT机,对50例心率≤70次/min患者行前瞻性门控,50例心率≤70次/min及50例心率＞70次/min患者行回顾性门控扫描模式下冠状动脉CT成像,对成像质量和X线剂量进行对比研究,经统计学处理分析2种扫描模式冠状动脉CT成像的图像质量差异及X线剂量差异.结果 2种扫描模式下冠状动脉CT成像的图像质量差异无统计学意义,前瞻性门控组中图像质量积分3分以上均达98%以上,全部病例图像质量均能满足诊断要求;2种扫描模式下X线剂量参数总剂量长度乘积值、总有效剂量差异有统计学意义(P＜0.001); 前瞻性门控扫描较回顾性门控扫描下心率＞70次/min及心率≤70次/min的X线总有效剂量分别下降75.15%及79.56%.结论 当受检者心率≤70次/min时,可选择时间窗为R-R间期70%前瞻性门控扫描,图像质量优良,并且能大幅度降低冠状动脉成像X线辐射剂量.