心率及心率波动对256层CT回顾性心电门控冠状动脉成像质量的影响简

目的 探讨心率及心率波动对256层计算机断层扫描（computerized tomography,CT）冠状动脉成像图像质量的影响.方法 150例疑为冠状动脉粥样硬化性心脏病（冠心病）的患者行256层CT回顾性心电门控冠状动脉检查,对直径＞1.5 mm的冠状动脉节段进行评分.根据平均心率分为3组：A组,心率＜65次/min;B组,65次/min～80次/min;C组,心率≥80次/min.比较不同心率组间的图像质量,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,并采用线性回归方程确定需进行干预的心率临界点.结果 在最佳重组时相上,可满足诊断要求的图像占97.9％.冠状动脉总体、右冠状动脉、左前降支及左旋支的图像质量评分与心率显著相关,相关系数分别为0.473、0.425、0.409、0.413（P均＜0.001）,冠状动脉图像质量与心率波动无明显相关（P＞0.05）.不同心率组间冠状动脉图像质量比较,差异有统计学意义（P＜0.05）.当心率＜83.1次/min时,可获得优良的图像质量,而为获取满足临床诊断要求的图像,心率应＜119.1次/min.心率＜65次/min时,舒张期重建的图像质量佳;心率＞71次/min时,收缩期重建的图像质量佳.结论 心率波动对256层CT同顾性心电门控冠状动脉图像质量无显著影响,但心率仍是影响图像质量的一个重要因素;降低心率有助于提高图像质量.

Impact of heart rate and heart rate variability on image quality in retrospectively ECG-gated 256-slice coronary CT angiography

Objectives To evaluate the impact of average heart rate and heart rate variability on image quality in 256-slice computed tomography （CT） coronary angiography.Methods Retrospectively electrocardiography （ECG）-gated coronary angiography using 256-slice CT was performed in 150 patients.And image quality of each coronary segment larger than 1.5 mm in diameter was rated.These patients were divided into 3 groups with the heart rate ＜65 beats/min as group A,65-80 beats/min as group B and ≥ 80 beats/min as group C.The image quality of coronary artery in different heart rate groups was compared.And Pearson correlation analysis was performed to observe the effect of average heart rate and heart rate variability on image quality.Regression analysis was performed to calculate heart rate thresholds for future intervention.Results Diagnostic image quality （score ≤ 3） was attained in 97.9％ segments at the best reconstruction interval.A significant correlation was observed between heart rate and coronary artery,right coronary artery,left anterior descending branch,left circumflex image qualities （r=0.473,0.425,0.409,0.413,all P＜0.001）,but not for heart rate variability and image quality（P＞0.05）.Significant difference was found in image quality of different heart rate groups （P＜0.05）.Good to excellent image quality and diagnostic image quality could be achieved at the heart rate of 83.1 and 119.1 or fewer beats per minute,respectively.Best image quality was obtained at diastole with heart rate lower than 65 beats/min and at systole with heart rate higher than 71 beats/min.Conclusions There is no significant impact of heart rate variability on image quality of 256-slice CT coronary angiography,while heart rate still plays a key role in obtaining good image quality.Reducing average heart rate is beneficial for getting better image quality.