优化临界心率采集方案对320排CT冠状动脉成像图像质量和辐射剂量的影响

Effect of Optimized Critical Heart Rate Acquisition Scheme on Image Quality and Radiation Dose of 320-slice CT Coronary Artery Imaging

目的:探讨优化临界心率采集方案对320排CT冠状动脉成像图像质量和辐射剂量的影响.方法:前瞻性收集2019年11月至2022年9月60例(呼吸训练屏气时平均心率为75-79次/min区间)行冠状动脉CT检查者,其中通过手动修改优化为1个心动周期采集者为A组(n=30),通过系统自动设置方案2个心动周期采集者为B组(n=30).记录扫描前平静呼吸时心率(静息心率)、呼吸训练屏气时心率(基础心率)、注射对比剂扫描中的心率(注射时心率)、图像质量和辐射剂量指标进行统计学分析.结果:A组、B组静息心率分别为(78.3±3.9)次/min、(79.1±3.7)次/min,基础心率分别为(76.8±2.7)次/min、(77.3±2.9)次/min,注射时心率分别为(73.8±3.0)次/min、(74.4±2.5)次/min.注射时心率<基础心率<静息心率,A组注射时心率比基础心率平均下降约(3.0±0.7)次/min,B组平均下降约(2.9±0.2)次/min.A组、B组辐射剂量分别为(1.36±0.46)mSv、(2.79±0.52)mSv,差异有统计学意义(t=-2.961,P<0.05).结论:静脉注射对比剂扫描时心率会有所下降,以此为基础调整优化的临界心率采集方案,可在保证图像质量的同时有效降低辐射剂量,使更多受检者获益,值得推广.

Purpose:To investigate the effect of optimized critical heart rate acquisition scheme on image quality and radiation dose of 320-slice CT coronary artery imaging.Methods:From November 2019 to September 2022,60 patients underwent coronary artery CT examination(the average heart rate during breath training was 75-79 beats per minute).Thirty patients in group A were optimized for one cardiac cycle by manual modification,and 30 patients in group B were collected through 2 cardiac cycles automatically set up by the system.The heart rate during quiet breathing(resting heart rate),the heart rate during breath holding in breathing training period(basic heart rate),the heart rate during contrast medium scanning(heart rate during injection)and radiation dose were recorded and statistically analyzed.Results:In group A and group B,the resting heart rate was(78.3±3.9)beats per minute and(79.1±3.7)beats per minute,respectively;the basic heart rate was(76.8±2.7)beats per minute and(77.3±2.9)beats per minute,respectively;the heart rate during injection was(73.8+3.0)beats per minute and(74.4±2.5)beats per minute,respectively.The heart rate during injection was lower than that during breath holding in breathing training period,and also lower than that during quiet breathing,and the average decrease of heart rate in group A and group B was (3.00±0.7) beats per minute and (2.90±0.2) beats per minute, respectively. The radiation dose in group A andgroup B was (1.36±0.46) mSv and (2.79±0.52) mSv, respectively, and the difference was with statistical significance(t=-2.961, P<0.05).Conclusions: The heart rate will decrease when intravenous contrast agent is injected. Based onthis, the optimized critical heart rate acquisition scheme can effectively reduce the radiation dose while ensuring theimage quality, so that more subjects can benefit, which it is worthy of promotion.