心率及心率波动对64层螺旋CT冠状动脉成像质量的影响

目的回顾性分析心率及心率波动对64层螺旋CT冠状动脉图像质量的影响。方法将129例疑为冠心病的患者行64层螺旋CT冠状动脉检查的原始数据在心动周期的40%～80%时相上进行图像重组。对直径>1.5mm冠状动脉节段进行评分(≤3分为满足临床诊断)。采用Pearson相关分析方法分析平均心率及心率波动对图像质量的影响。结果扫描时所有患者心率33～108次/min,平均62.2次/min。心率波动0.2～46.9次/min,平均4.4次/min。在最佳重组时相上,可满足诊断的图像占93.9%。图像质量与平均心率及心率波动显著相关。心率<69.7次/min及心率波动<15.7次/min时,可获得优良的图像质量;心率<63次/min时,舒张期重组的图像质量佳;心率>67次/min时,收缩期重组的图像质量佳。重组时相窗从舒张期切换至收缩期的心率范围为63～67次/min。结论心率及心率波动对64层螺旋CT冠状动脉图像质量有重要影响,减低心率及心率波动可提高图像质量。

Effect of heart rate and heart rate variability on image quality of coronary angiography with 64-slice CT

Objective To evaluate retrospectively the effect of average heart rate and heart rate variability on image quality of 64-slice computed tomographic(CT)coronary angiography.Methods 129 patients were studied with 64-slice CT coronary angiography.Data sets were reconstructed from 40% to 80% of R-R interval.Image quality of each coronary segment at least 1.5 mm in diameter was rated.Pearson correlation analysis was performed to observe the effect of average heart rate and heart rate variability on image quality of each patient.Results Diagnostic image quality(score≤3)was attained in 93.9% segments at the best reconstruction interval.Image quality was correlated with heart rate and heart rate variability.Good to excellent image quality could be achieved at heart rates of 69.7 or fewer beats per minute and heart rate variability of 15.7 or fewer beats per minute.Best image quality was obtained at diastole with heart rate lower than 63 beats per minute and at systole with heart rate higher than 67 beats per minute.Conclusion Image quality of 64-slice CT coronary angiography is highly dependent on average heart rate and heart rate variability.Reducing average heart rate and heart rate variability is beneficial to reducing artifacts.