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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。
Objective: To investigate the influence of dynamic 500-row volumetric spiral shuttle (VHS) with adaptive statistical iterative reconstruction (ASiR) platform on CT perfusion imaging of liver tumors. Methods: The dynamic data of 28 patients diagnosed with liver cancer were examined by CT perfusion imaging. The original data were reconstructed by FBP (reconstruction thickness 2.5 mm). The CT values of abdominal aorta were measured. Noise and hepatic tumor perfusion parameters including surface permeability (PS), mean transit time (MTT), hepatic blood flow (BF), hepatic blood volume (BV), Wilcoxon signed-rank test and two reconstruction algorithms The differences in the values of various perfusion parameters. Two radiologists subjectively evaluated the two groups of images. Results: Compared with FBP and reconstruction, the CT values of 40% ASi R were (58.33 ± 9.19) and (58.78 ± 9.30) HU, respectively, with no significant difference (P = 0.258) (10.9 ± 1.49) was significantly lower than that of FBP group (13.20 ± 1.65), the difference was statistically significant (P <0.01). The perfusion parameters (PS, MTT, BV and BF) measured by the two reconstruction algorithms There was no significant difference (P> 0.05). The image quality score of 40% ASi R group (4.25 ± 0.42) was higher than that of FBP group (3.79 ± 0.48), the difference was statistically significant (P = 0.001); the subjective score of the two groups of images had good agreement (Kappa = 0.821). CONCLUSION: Dynamic 500-slice scanning technique based on ASi R platform can effectively reduce the image noise of 40% ASi R algorithm and significantly improve the quality of CT in liver tumor perfusion imaging. The measured perfusion parameters and FBP reconstruction algorithm compared to no significant difference.