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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。
Objective: To study the influence of different scanning conditions of single-source dual-energy CT on the stability of water concentration. Methods: Single-source dual-energy CT (GE Discovery HD750) was used to select different scanning parameters for sequential combination scanning of standard water phantoms. The scanning parameters include: tube current: 260,275,360,375,550,600,630, 640m A; Rotational speed: 0.5,0.6,0.7,0.8,0.9,1.0 s / r; Scanning field: abdominal large and medium; Reconstruction layer thickness / spacing: 5mm, 5mm, 1.25mm, 1.25mm; Pitch: 1.375mm and 0.984 mm. A total of 552 sets of data were scanned and water-iodine images were generated by GSI general MD analysis software to measure the water concentration (ROI = 600 ± 30mm2) in the middle of each series. The stepwise function in Matlab 7.11.0 software was used to analyze the measured data to get the effect of five different scanning parameters on water-iodine concentration. Results: Four factors (speed, current, scan field and pitch) had significant effects on the change of water - iodine concentration (P <0.05), and the influence of rebuilt layer thickness on water - iodine concentration was not significant (P = 0.353) . CONCLUSION: Different scanning conditions affect the concentration of water-iodine in single-source dual-energy CT. The effects of rotation speed, current, scanning field and pitch on water iodine concentration are significant. The reconstruction layer thickness has no obvious effect on water-iodine concentration influences.