16层螺旋CT冠状动脉造影质量的影响因素研究

目的:探讨16层螺旋CT冠状动脉血管造影质量的影响因素。方法:选择219例受检者行16层螺旋CT冠状动脉血管造影检查,层厚为1.25mm或0.625mm,pitch值0.325,注射速度3ml/s~5ml/s,所得的原始轴位图像传到后处理工作站进行三维重建,通常采用曲面重建(CPR),多平面重建(MPR),最大密度投影(MIP),容积重现(VR)和模拟血管内窥镜(VE)显示冠状动脉主干及其主要分支。结果:心率的快慢、心率的波动及后期重建的时相都会对心脏的最终图像质量产生影响,心率波动产生较多阶梯状伪影;心率平稳,心率在55次/min~75次/min,多层螺旋CT(MSCT)对冠状动脉主干主要分支85%以上达到诊断要求;心率>75次/min时,选取40%~50%时相图像质量最好;心率>90次/min时,冠状动脉的主要分支显示欠清。结论:心率平稳且<75次/min,使用合适的重建相位窗、对比剂及扫描参数,MSCT可得到满意冠状动脉影像。

Study on the Factors that Interference the Image Quality of 16 Slice Spiral CT in Coronary Angiography

Objective To assess the factors that interference the image quality of 16 slice spiral CT in coronary angiography. Methods There were 219 patients accepted the coronary angiography test with 16 slice spiral CT,which had 1.25 mm or 0.625 mm-thick-section,0.325 of pitch,rate 3 ml/s -5 ml/s of the injection. The primitive axial image could be reconstructed as three-dimensional in the after-finishing work-station. CPR,MPR,MIP,VR,VE modes were adopted to display the bole and the mainly branch of the coronary. Results Speed or fluctuation of heart rate or the phase of the after stage reconstitution influenced the final image quality, the fluctuation of heart rate generated many ladder-like shadow; It reached -the requisition of the diagnosis. When the stable heart rate waved between 55 bpm to 75 bpm , the manifestation of the bole and the mainly branch of the coronary was 85% according to MSCT. when exceeded 75 bpm, the 40% ～ 50% phase image quality was the best＇ ;when exceeded 90 bpm, the mainly branch of the coronary was not clear. Conclusion When the stable heart rate was lower than 75 bpm, the image quality of the coronary was content with MSCT in coronary angiography, using suitable phase-win- dow reconstruction ,contrast agent and scanning parameter.