64层螺旋CT冠脉成像心电门控低剂量技术的基础研究

目的通过动态心脏模具,对采用ECG管电流调制技术的CT低剂量冠状动脉成像的相关因素进行分析,并探讨不同心率条件下ECG管电流调制技术选择.方法使用64层GE LightSpeed VCT并选择不同心率条件,分别在开启和关闭ECG管电流调制技术条件下扫描动态心脏模具,对不同心率和扫描条件下的剂量变化和图像质量进行统计分析.结果 （1）相比常规模式,ECG管电流调制技术下最大管电流调制期相为79%～99%的R-R间期时,最多可节约26%的射线剂量,最大管电路调制期相为90%的R-R间期时,则最多能够节约36%的射线剂量,差异有统计学意义（P〈0.05）;（2）心率对冠状动脉成像检查图像质量的影响,对是否开启ECG管电流调制技术均较明显;（3）心率存在波动时,开启ECG管电流调制技术,会使图像噪声增加,当波动≤10bpm时,重建冠脉图像质量满足诊断要求.结论开启ECG管电流调制技术对不同心率条件下CT冠状动脉成像检查均可以有效降低检查的有效剂量,但为保证冠状动脉图像质量,需结合患者心率变化情况,将电流调制的期相范围合理设置,以期低剂量检查做到行之有效.

Basic Study of Electrocardiograph Modulated Milliampere with 64-MSCT in Coronary Artery Imaging

Objective To analysis the relevant factors of ECG modulated mA with 64-MSCT in coronary artery imaging,and to explore the best settings of ECG modulated mA in different heart rate,by using the dynamic cardiac phantom.Methods GE Lightspeed VCT with and without ECG modulated mA was used to scan the dynamic cardiac phantom in different heart rate. The image quality and radiation dose in different condition were statistically analyzed.Results（1） The radiation dose with 79%～99% R-R interval and 90% R-R interval ECG modulated mA were maximized decreased by 26% and 36% respectively.Compared to that of without ECG modulated mA,there is a statistical differencebetween two modes in radiation dose（P0.05） .（2） The heart rate had significant influences on the coronary artery image quality with and without ECG modulated mA.（3） If the heart rate was instable,scan with ECG modulated mA would increase image noise;But when the heart rate fluctuation level was 10 bpm,the coronary artery image was enough to meet the diagnostic requirements.Conclusion Our results indicate that 64-MSCT in coronary artery imaging with ECG modulated mA can reduce the radiation dose,but ECG modulated mA must be set rationally according to heart rates.