不同扫描条件对单源双能CT水-碘浓度值稳定性的影响

The Influence on the Stability of Water-iodine Concentration in Different Single-Source Dual-Energy CT Scanning Conditions

目的:研究单源双能CT的不同扫描条件对水浓度值稳定性的影响。方法:使用单源双能CT(GE Discovery HD750)选取不同的扫描参数进行有序组合对标准水模进行扫描,扫描参数包括:管电流:260、275、360、375、550、600、630、640m A;转速:0.5、0.6、0.7、0.8、0.9、1.0 s/r;扫描野:腹部large和medium;重建层厚/间距:5mm、5mm、1.25mm、1.25mm;螺距:1.375mm和0.984mm。共扫描552组数据,利用GSI general MD analysis软件后处理生成水-碘图像,测量每个序列的中间层面图像中心区水浓度值(ROI=600±30mm2)。采用Matlab 7.11.0软件中的stepwise函数对测量所得数据进行分析以获得5个不同扫描参数对水-碘浓度值影响的大小。结果:转速、电流、扫描野、螺距4个因素对水-碘浓度值的变化有显著影响(P<0.05),重建层厚对水-碘浓度值的影响无统计学意义(P=0.353)。结论:不同扫描条件对单源双能CT的水-碘浓度值有影响,其中转速、电流、扫描野、螺距对水碘浓度值的影响较为显著,重建层厚对水-碘浓度值无明显影响。

Purpose：To investigate the influence on the stability of water-iodine concentration in different single-source dual-energy CT scanning conditions. Methods：A GE standard water model was scanned by different scanning parameters of single-source dual-energy CT. Five hundred and twenty-two groups of data was acquired by scanning parameters orderly combined below： tube current： 260,275,360,375,550,600,630,640 m A）; speed： 0.5,0.6,0.7,0.8,0.9,1.0s/rot）; FOV： large and medium; thickness： 5mm,1.25mm; pitch： 1.375 mm,0.984 mm. The central water concentration of each sequence on iodine-water images,which were reconstructed by GSI general MD analysis software（ROI=600±30mm^2）,was recorded. Influence of different scan parameters on the water concentrationwas analyzed with stepwise model on Matlab 7.11.Result：Speed,tube current,FOV and pitch were all with significant influence on water-iodine concentration,but thickness was with no significant influence（P =0.3530.05）. Conclusion：Different scanning parameters of single-source dual-energy CT have influence on water-iodine concentration,especially the parameters of speed,tube current,FOV and pitch.