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目的采用新型心脏动态体模,对16层螺旋CT冠状动脉成像图像质量相关影响因素进行分析,并探讨在不同心率下的扫描速度和重组算法选择。材料与方法采用GE公司研制的新型心脏动态体模,心率设置为40~95次/min(间隔5次/min)共12组。采用GE LightSpeed16层螺旋CT,以心脏冠状动脉扫描模式对不同心率下的心脏体模进行扫描,X线球管转速(即扫描速度)设置为0.5s/r和0.6s/r。所有的扫描数据在R-R间期90%时相分别以单扇区(Snapshot segment)、双扇区(Burst-2)和四扇区重组(Burst-4)3种心脏重组算法进行重组。所有重组数据传至AW4.1工作站行后处理成像。后处理方法采用容积再现(VR)、多平面重组(MPR)。分别对不同重组图像进行评分。统计学处理采用析因分析和多元线性回归分析。结果(1)总模型具有统计学意义(F=11.15,P<0.0001),不同心率(F=11.99,P<0.0001)、不同转速(F=5.76,P=0.00196)、不同重组算法(F=9.21,P=0.0003)对图像质量有显著的影响,三者的交互作用均无显著差别(P>0.05);(2)不同心率间比较,心率≤65次/min时图像质量评分较高(P<0.05);(3)不同扫描速度比较,0.5s/r时,图像质量评分较高(P<0.05);(4)不同重组算法之间比较:重组算法为Burst-4和Burst-2时,图像质量评分较高(P<0.05),但两者之间差异无统计学意义(P>0.05);(5)心率、扫描速度及重组算法与图像质量间具有多元线性回归关系(标准化回归系数分别为-0.70794、-0.16449和0.27341,F=34.43,P<0.0001),各回归系数具有显著性。结论心率、扫描速度及重组算法等是影响16层螺旋CT冠状动脉成像图像质量的主要因素,可采用新型心脏动态体模进行评估。合理利用扫描参数能有效提高图像质量和检查的成功率。
Objective To analyze the influencing factors of the 16-slice spiral CT coronary angiography image quality by new cardiac dynamic phantom and to explore the scanning speed and recombination algorithm selection under different heart rates. Materials and Methods A new type of heart dynamic phantom developed by GE Company was used. The heart rate was set at 40 to 95 beats / min (interval 5 times / min) for a total of 12 groups. Using GE LightSpeed 16-slice spiral CT, cardiac phantoms at different heart rates were scanned in coronary heart scan mode. X-ray tube rotational speed (ie, scan speed) was set at 0.5 s / r and 0.6 s / r. All the scanned data were reconstructed by three kinds of cardiac recombination algorithms of single shot (Snapshot segment), double-burst (Burst-2) and four-sector burst (Burst-4) at 90% of the R- All reorganized data is transmitted to the AW4.1 workstation post-processing imaging. Post-processing methods using volume reproduction (VR), multi-plane reorganization (MPR). Respectively, different reorganized images were scored. Statistical analysis using factorial analysis and multiple linear regression analysis. Results The total model had statistical significance (F = 11.15, P <0.0001), different heart rate (F = 11.99, P <0.0001), different rotation speed (F = 5.76, P = 0.00196) 9.21, P = 0.0003) had a significant effect on the image quality, and there was no significant difference in the interaction between them (P> 0.05); (2) The image quality score was higher when the heart rate was less than 65 beats / P <0.05); (3) The image quality score was higher at 0.5s / r at different scanning speeds (P <0.05); (4) Comparison between different recombination algorithms: the recombination algorithm was Burst-4 and Burst-2 (P <0.05), but there was no significant difference between them (P> 0.05). (5) The multiple linear regression of heart rate, scanning speed and recombination algorithm with image quality The regression coefficients were -0.70794, -0.16449 and 0.27341, respectively, F = 34.43, P <0.0001), and the regression coefficients were significant. Conclusions Heart rate, scanning speed and recombination algorithm are the main factors influencing the quality of 16-slice spiral CT coronary angiography. They can be evaluated by new cardiac dynamic phantom. Rational use of scanning parameters can effectively improve the image quality and the success rate of inspection.