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目的采用心脏动态体模,对64层螺旋 CT 冠状动脉成像图像质量的相关影响因素进行分析。方法采用 GE Light speed 64层螺旋 CT,以心脏扫描的模式对心脏动态体模进行扫描。心脏动态体模由3部分组成:动力部分、解剖结构模拟部分和控制部分组成。心率设置为40、45、50、55、60、65、70、75、80、85、90、95、100、105、110和115次/min,X 线管转速设置为每转0.35、0.40和0.45 s,分别对不同心率下的心脏动态体模进行冠状动脉成像扫描。所有扫描数据在 R-R 间期90%时相分别进行单扇区和多扇区重组。重组数据传至 AW 4.2工作站后处理成像。后处理方法采用容积重组(VR)、多平面重组(MPR)模式。分别对不同重组图像进行评分。统计学处理采用多元线性回归模型。结果 (1)心率对图像质量的影响有统计学意义(P<0.01),随着心率的增加,图像质量评分呈下降趋势。多元线性回归分析显示心率每增加1次,图像质量评分平均减低0.046;(2)重组算法对图像质量的影响有统计学意义(P<0.01),在同一条件下多扇区重组算法较单扇区重组算法能增加图像质量评分0.5。(3)X 线管转速在0.35、0.40和0.45 s 下对图像质量的影响无统计学意义(P>0.05),在40～115 次/min 心率时的重组图像,得到的最高评分时 X 线管转速分别为0.35和0.45 s。(4)心率、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-0.824和0.194)。结论心脏动态体模评价64层螺旋 CT 冠状动脉成像图像质量的影响因素,能够为其临床应用和基础研究提供帮助。
Objective To analyze the influential factors of coronary artery imaging with 64-slice spiral CT in cardiac dynamic phantom. Methods GE Light speed 64-slice spiral CT was used to scan cardiac dynamic phantom in cardiac scanning mode. Cardiac dynamic phantom consists of 3 parts: power part, anatomical structure and control part of the simulation part. The heart rate was set at 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, and 115 beats / min and the X-tube speed was set at 0.35, 0.45 s, respectively, under different heart rates of cardiac dynamic phantom coronary imaging. All scan data are individually sectorized and multi-sectorized at 90% of the R-R interval. The reassembled data is sent to the AW 4.2 workstation for post-processing imaging. Post-processing methods using volume reorganization (VR), multi-plane reorganization (MPR) mode. Respectively, different reorganized images were scored. Statistical analysis using multiple linear regression model. Results (1) The influence of heart rate on image quality was statistically significant (P <0.01). With the increase of heart rate, the image quality score showed a downward trend. Multivariate linear regression analysis showed that the image quality score decreased by 0.046 on average for each increase of heart rate. (2) The effect of recombination algorithm on image quality was statistically significant (P <0.01). Under the same conditions, Region recombination algorithm can increase the image quality score 0.5. (3) X-ray tube speed had no significant effect on the image quality at 0.35, 0.40 and 0.45 s (P> 0.05), at the time of 40 ~ 115 breaths / min, Tube speed were 0.35 and 0.45 s respectively. (4) There was a multiple linear regression between heart rate, recombination algorithm and image quality (normalized regression coefficients were -0.824 and 0.194, respectively). Conclusion Cardiac dynamic phantom evaluation of 64-slice spiral CT coronary angiography image quality factors that can help its clinical application and basic research.