不同迭代重建强度对冠状动脉小内径支架显示影响的体外实验

Visual improvement for 3 mm or less coronary artery stent imaging by using different iterative reconstruction strength grade:An in vitro experiment

目的评价联合基于原始数据的迭代重建（SAFIRE）与集成电子探测器在不同迭代重建强度下对直径≤3mm冠状动脉支架显示的影响。方法选取不同类型7枚内径3mm或2.5mm支架,释放于模拟冠状动脉血管的体外模型中,行配有Stelllar光子探测器的双源CT冠状动脉前瞻扫描,层厚0.5mm,按迭代重建强度Strength 1~4重建分为4组。对4组图像行双盲主观评价和客观评价[包括支架内径差异（ALN）、支架内腔衰减和图像噪声],对各组数据进行统计学分析。结果图像质量主观评分一致性较好（Kappa=0.77）,Strength 2组获取的图像质量明显优于其他各组（P=0.034、0.046、0.015）。Strength 2组ALN值明显低于其他各组（P=0.013、0.009、0.005）。各组支架管腔内衰减差异无统计学意义（P均〉0.05）。随着迭代强度增加,噪声明显降低。结论对于直径≤3mm支架,联合SAFIRE迭代强度2与集成电子探测器获取的图像质量整体最佳,可为临床提供质量更好的支架图像。

Objective To evaluate the influence on ≤3 mm coronary artery stent visualization by using different sinogram affirmed iterative reconstruction （SAFIRE） strength grade combined with integrated circuit detector. Methods Seven 3 mm or 2.5 mm coronary artery stents were selected to make in-vitro coronary artery model. Prospective coronary artery scan using Definition Flash CT with Stellar detector was performed. The data by different iterative reconstruction strength grades （divided into Strength 1--4 group） with 0.5 mm slice thickness were reconstructed. Double-blind and independent qualitative and quantitative assessment including artificial lumen narrowing （ALN）, luminal attenuation difference and im- age noise among groups were performed, and the differences between the groups were analyzed. Results The interobserv- er agreement for image subjective quality scores was good （Kappa=0. 77） , the image quality of the Strength 2 group was significantly higher than other groups （P=0. 034, 0. 046, 0. 015）. The ALN of the Strength 2 group was the lowest, and had statistically significant differences between other groups （P= 0. 013, 0. 009, 0. 005）. But the value of the lumin- al attenuation difference between the four groups all had no statistical significance （all P〉 0.05 ）. With the increasing of the iterative reconstruction strength grades, the image noise decreased obviously. Conclusion For ≤3 mm coronary artery stents, combining integrated circuit detector with iterative reconstruction strength 2 can provide the best over-all image quality.