64层探测器CT冠状动脉成像依据不同心率的最佳重建方案

64 detector row computed tomographic coronary angiography optimization of image reconstruction protocol according to the heart rate

目的:探讨64层螺旋CT冠状动脉成像不同心率下冠状动脉各节段血管的最佳重建时相。方法:对61例患者行64层螺旋CT冠状动脉成像,扫描后原始数据分别按R-R间期30%、35%、40%、45%、50%、60%、70%、75%的相位进行后处理重组,按扫描期间平均心率分组,Ⅰ组30例,心率<70次/min;Ⅱ组31例,心率≥70次/min。分析不同心率组不同R-R时相对各支冠状动脉血管的显示情况。结果:Ⅰ组的所有的冠状动脉节段可以在单一的75%相位上获得最佳图像质量;Ⅱ组的所有冠状动脉可以在单一的45%或40%的相位上获得最佳图像质量,多时相重建并不能显著提高图像质量。结论:随着64层螺旋CT时间分辨率的充分发展,所有冠状动脉节段能在一个重建时相得到有诊断价值的图像,多时相重建并不能显著提高图像质量。

Objective：To explore the optimal reconstruction protocol of coronary artery angiography with 64 detector-row CT according to the heart rate.Methods：Sixty-one patients underwent coronary angiography using 64detector-row CT.Raw helical CT data were reconstructed at 30%～75% of the cardiac cycle with increments of 5% by several postprocessing techniques.Sixty-one patients were divided into two groups：group Ⅰ（n=30）with heart rates less than 70 bpm;group Ⅱ（n=31）with heart rates more than 70 bpm;Image quality score（IQS）was assessed by independent observers using a 5-point scale from non-diagnostic（1）to excellent（5）.The image quality of coronary artery in different reconstruction phases for different groups was evaluated.Results：At heart rates 70 bpm,diagnostic image quality of all coronary segments can be obtained at a single reconstruction R-R phase of 75%.At heart rates ≥70 bpm,the optimal image quality was found in all coronary segments at a single reconstruction R-R phase 45% or 40%.Conclusion：By using 64-row multidetector CT,the need for adjusting the reconstruction point to each coronary segment might be overcome.Best image quality was achieved with image reconstruction at a single reconstruction R-R phase for all coronary segments as well as each coronary artery.