320排CT冠状动脉成像平均心率对图像质量和辐射剂量的影响

目的:探讨不同心率条件下320排容积CT冠状动脉血管成像的图像质量和辐射剂量.方法:将259例临床怀疑或确诊的冠状动脉疾病的患者(含35例心律失常患者)分为3组；A组79例,心率≤65次/分；B组120例,65＜心率＜80次/分；C组60例,心率≥80次/分.扫描完成后选用最佳的重建时相,对冠状动脉进行容积再现(VR)...

Impact of mean heart rate on image quality and radiation dose in 320-detector coronary artery angiography

Objective：To evaluate the image quality and radiation dose of coronary computed tomography angiography （CTA） on patients with various heart rate using320-detector CT scanner.Methods：A total of two hundred and fifty nine patients who were suspected or known with coronary artery disease underwent coronary CTA.These patients were divided in three subgroups： group A（79 cases）,with heart rate below 65 beats per minute;group B（120 cases）,with heart rate from 65 to 80 beats per mminute;group C（60 cases）,with heart rate more than 80 beats per minute.All images with best phase were transferred to a workstation for further post-processing,including VR,MIP,MPR and CPR.Image quality was scored based on 4-point Likert scale in a coronary segmental basis.Statistic analysis was made for grade of image quality and radiation dose,and the relationship between the heart rate and radiation dose was analyzed.Results： No significant difference was found for image quality scale and score in group A,group B and group C（χ2 = 4.216,P = 0.121）.Nonassessable segments were not found in 35 patients with arrhythmias.Positive correlation was shown between heart rate and image quality score（r = 0.177,P = 0.000）.Mean effective dose was（3.47 ± 2.48） mSv,（10.28 ± 4.25） mSv,（15.76 ± 6.09） mSv in group A,B and C respectively,there was a significant difference（χ2 = 149.14,P = 0.000）.Positive correlation was found between heart rate and effective dose（r = 0.401,P 0.001）.Conclusion： 320-detector CT scanner can provide diagnostic image quality within relatively wide range of heart rate and be relevantly adaptive to higer heart rate.Radiation dose was reduced especially for patients with heart rate below 65 beats per minute.