Objective To explore the application value of multi-model adaptive statistical iterative reconstruction-Veo (ASiR-V) in ultra-low dose chest CT examination of children in the plateau area. Methods The children who underwent chest CT examination in Xizang Autonomous Region People's Hospital were enrolled in this study and assigned into two groups according to the scanning conditions.Group A underwent scanning at a tube voltage of 100 kV and ASiR-V 50% reconstruction,and group B underwent scanning at a tube voltage of 80 kV and ASiR-V 0 (Group B1) and ASiR-V 50% (Group B2) reconstruction.The image quality of each group was evaluated objectively and subjectively.The radiation dose and image quality were compared between groups. Results Groups A and B showed the volume CT dose indexes of (2.33±0.62) mGy and (0.86±0.01) mGy and the dose length products of (65.01±25.12) mGy·cm and (23.55±3.38) mGy·cm,respectively,which presented differences between groups (both P<0.001).The image noise in the bilateral upper and middle lung areas in group B2 was lower than that in group B1 but higher than that in group A (all P<0.001).There was no significant difference in image quality score of the lung window among groups (all P>0.05).Groups A,B1,and B2 had no significant differences in ascending aorta (P=0.538) or liver CT value (P=0.175) in the mediastinal window.The signal-to-noise ratios and contrast-to-noise ratios of ascending aorta and liver in group B2 were higher than those in group B1 (all P<0.001) and lower than those in group A (all P<0.05).The image quality score of the mediastinal window followed a descending order of group A>group B2>group B1 (all P<0.001). Conclusion ASiR-V combined with low tube voltage can effectively reduce the radiation dose and guarantee the image quality of chest CT of children in the plateau area.
目的 探讨多模型自适应统计迭代重建(ASiR-Ⅴ)算法在高原地区儿童超低剂量胸部CT检查中的应用价值。方法 收集西藏自治区人民医院行胸部CT检查的儿童患者,根据扫描条件分为两组:A组采用管电压100 kV,并进行ASiR-Ⅴ 50%重建;B组采用管电压80 kV,分别进行ASiR-Ⅴ 0(B1组)和ASiR-Ⅴ 50%(B2组)重建,对各组图像质量进行主观及客观评分,比较各组的辐射剂量及图像质量。结果 A组和B组容积CT剂量指数分别为(2.33±0.62)、(0.86±0.01)mGy,两组比较差异有统计学意义(P＜0.001),剂量长度乘积分别为(65.01±25.12)、(23.55±3.38)mGy·cm,两组比较差异有统计学意义(P＜0.001)。肺窗B2组双上肺、双中肺噪声值低于B1组,但均高于A组(P均＜0.001);各组肺窗图像质量评分比较差异均无统计学意义(P均＞0.05)。纵隔窗A组、B1组和B2组升主动脉(P=0.538)和肝脏CT值(P=0.175)比较差异无统计学意义,B2组升主动脉和肝脏信噪比(P均＜0.001)、对比噪声比(P均＜0.001)均高于B1组,且低于A组(P均＜0.05);纵隔窗图像质量评分A组高于B2组,且均高于B1组(P均＜0.001)。结论 ASiR-Ⅴ联合低管电压在有效降低辐射剂量的同时,能够保障高原地区儿童胸部CT的图像质量。.
Keywords: adaptive statistical iterative reconstruction-Veo; children; low dose; multislice spiral CT.