非刚性配准运动校正算法与双扇区重组对改善冠状动脉CTA图像质量的对比分析

目的一种基于非刚性配准的运动校正算法智能边缘修复技术(intelligent boundary registration,IBR)已应用于冠状动脉CTA成像。通过与双扇区重组图像质量的比较,评估IBR技术应用于冠状动脉成像的效果。方法本回顾性研究经医院伦理委员会批准,并获得患者的知情同意。收集本院行能谱CT冠状动脉CTA检查且平均心率为65次/min(范围58~75次/min)的70例可疑心肌缺血患者,在最佳心动时相进行双扇区图像重组(SSB2),即为SSB2组;在最佳心动时相进行单扇区图像重组,基于最佳单扇区重组执行IBR重组以生成IBR图像,即为IBR组。采用5分制评分(5=图像质量优秀;1=不能满足诊断要求),评价指标包括:整体图像质量、血管的评估(连续性、有无运动伪影、血管的边缘模糊与否)。由两位心血管放射学医师通过双盲和独立观察比较,对SSB2和IBR处理后的图像分别进行冠状动脉整体水平和冠状动脉节段评分。结果共分析了70位患者冠状动脉的984个节段。两位医师的评分结果具有良好的一致性(k0.81),SSB2组和IBR组的平均评分分别为(4.02±1.28)和(4.45±1.01),两者间的差异具有统计学差异(Z=-9.22,P0.01)。在基于冠状动脉节段的分析中,可接受的图像质量不低于3分的百分比分别为88.3%和91.2%,具有统计学差异(X~2=5.68,P0.05);可接受的图像质量不低于4分的百分比为分别为73.3%和88.5%,具有统计学差异(X~2=6.47,P0.05)。在重组的血管中不可评估的节段IBR组明显低于SSB2组,差异具有统计学意义(4.2%与9.5%,X~2=12.13,P0.01)。结论能谱CT冠状动脉IBR技术可以提高冠状动脉CTA的图像质量,减少阶梯状伪影。

Improving the image quality of coronary CT angiography using a novel non-rigid registration based motion correction algorithm: in comparison with bi-sector reconstruction

Objective Intelligent boundary registration (IBR) is a novel non-rigid registration based motion correction algorithm and is recently introduced for coronary CT angiography (CTA).The aim of this study was to compare the image quality of IBR with that of bi-sector reconstruction in coronary CTA.Methods Coronary CTA was performed on 70 patients with mean heart rates of 65 bpm (range:58-75 bpm) using a 64-row MDCT scanner.Bi-sector muhiphase reconstructions were performed to select the optimal cardiac phase.Single sector reconstruction was used to select the optimal cardiac phase.IBR reconstruction was then performed based on the optimal single sector reconstruction to generate the IBR images.The image quality was evaluated by two blinded and independent observers on the workstation using a 5-point scale (5=excellent to 1 =non-diagnostic).The image quality of the two reconstruction methods was compared.Evaluation criteria included overall image quality,continuity,motion artifacts,blurred or sharp edges of blood vessels.Results A total of 984 coronary artery segments from 70 patients was analyzed.There was good inter-observer agreement (k ＞0.81).The average score of IBR (4.45±1.01) was significantly higher (Z=-9.22,P＜0.01) than that of bi-sector reconstruction (4.02± 1.28).On coronary artery segment analysis,the percentage of acceptable image quality score ≥ 3 or ≥4 was significantly higher (x2=5.68,P＜0.05;x2=6.47,P＜0.05) with IBR (91.2％,88.5％) than bi-sector reconstruction (88.3％,73.3％).IBR reconstruction showed significantly lower (x2=12.13,P＜0.01) non-assessable segments (4.2％) than bisector reconstruction (9.5％).Conclusion IBR improves the image quality of coronary CTA,especially in patients with stair-step artifacts.