动态500排联合ASiR技术对肝脏肿瘤CT灌注成像参数的影响

目的:探讨具有自适应统计迭代重建(ASi R)平台的动态500排容积螺旋穿梭技术(VHS)对肝脏肿瘤CT灌注成像参数的影响。方法:28例确诊肝脏肿瘤患者行动态首次通过法CT灌注成像检查,所得原始数据采用滤波反投影(FBP)法进行重建(重建层厚2.5 mm),测量二组图像腹主动脉CT值、噪声及肝脏肿瘤灌注参数,包括表面通透性(PS)、平均通过时间(MTT)、肝血流量(BF)、肝血容量(BV),采用Wilcoxon符号秩和检验分析两种重建算法所测量的各项灌注参数值的差异。由两名放射科医师对2组图像质量进行主观评价。结果:40% ASi R与FBP和重建算法比较:腹主动脉CT值分别为(58.33±9.19)和(58.78±9.30) HU,差异无统计学意义(P=0.258);40% ASi R组图像噪声(10.9±1.49)明显低于FBP组(13.20±1.65),差异有统计学意义(P<0.01);两种重建算法所测量的各项灌注参数(PS、MTT、BV和BF)值差异均无统计学意义(P>0.05)。40% ASi R组图像质量评分(4.25±0.42)高于FBP组(3.79±0.48),差异有统计学意义(P=0.001);两组图像的主观评分结果一致性较好(Kappa=0.821)。结论:基于ASi R平台的动态500排扫描技术在肝脏肿瘤CT灌注成像中,40% ASi R算法的图像噪声有效降低,质量显著改善。所测量的各项灌注参数与FBP重建算法相比无明显差异。

Effect of Volume Helical Shuttle Mode with ASiR Technique on the Quality of CT Perfusion Imaging in Liver Tumor

Objective: To investigate the effect of VHS mode with ASi R on the quality of CT perfusion images of liver tumors. Methods: Twenty-eight patients with liver tumor underwent first-pass perfusion CT with volume helical shuttle technique. The raw date had been reconstructed by using FBP, the slice thickness being 2.5 mm. The CT values of aorta and the image noise were recorded for both groups. The parametric maps for the permeability surface(PS), blood volume(BV), blood flow(BF), transit time mean(MTT) were calculated. Paired samples t test or Wilcoxon signed sum test was used to analyze the difference.Image quality was assessed by two radiologists. Results: Compared with FBP reconstruction technique, 40% ASi R demonstrates low image noise((13.20 ±1.65) vs(10.9 ±1.49), P<0.01), with no statistical difference in CT values of aorta((58.33 ±9.19) vs(58.77 ±9.30), P=0.258). All the functional parameters of CT perfusion between two groups, including PS, BV, BF and MTT, showed no statistical difference. 40% ASi R group as quality score(4.14 ±0.36) higher than that of group FBP(3.79 ±0.48), the difference was statistically significant(P=0.001); Conclusion: Application of ASi R demonstrates no influence parameters acquired from CT perfusion with VHS mode in liver tumor, though the noise is lower than FBP.