基于胸围大小优化前置多模型迭代重组技术在胸部低剂量CT扫描的应用

Application of A Preset Adaptive Statistical Iterative Reconstruction Veo (ASIR-V) in Chest Low-Dose CT Scanning Based on Chest Circumference-Adapted

目的探讨基于胸围大小优化前置多模型迭代重组(ASIR-V)技术在胸部低剂量CT扫描中的应用价值。方法搜集行胸部CT平扫的健康体检者450名,依照胸围大小分为3组,每组150名。A组胸围<90 cm,B组90~100 cm,C组>100 cm。每组再随机分为5个亚组(n=30),各亚组前置ASIR-V比值范围为0~80%,以20%间隔递增。比较不同胸围范围内,各亚组间图像质量和辐射剂量的差异。图像质量的客观评价及辐射剂量比较采用单因素方差分析,主观评分采用Kruskal-Wallis H检验。结果 A、B和C组,随着前置ASIR-V比值的升高各亚组图像噪声略降低;降主动脉对比噪声比(CNR)值略升高,前置60%ASIR-V时最高,但组间差异无统计学意义;各组间辐射剂量逐渐降低,差异有统计学意义(P<0.000)。相同胸围范围内,前置60%ASIR-V时肺窗和纵膈窗图像质量的整体评分开始下降,A组和B组,前置80%ASIR-V时纵隔窗分值较其余各亚组差异有统计学意义(P<0.05);C组前置80%ASIR-V亚组肺窗和纵隔窗评分在3分以下,影响诊断,且较其余亚组差异有统计学意义(P<0.05)。结论胸部低剂量CT扫描依据检查者胸围大小选择最佳的前置ASIR-V权重比值,可在保证图像质量前提下降低辐射剂量。当胸围<100 cm时,推荐使用前置80%ASIR-V重组;当胸围>100 cm时,推荐使用前置60%ASIR-V重组。

Objective To investigate the value of preset adaptive statistical iterative reconstruction Veo(ASIR-V)technique in chest CT low-dose scanning based on chest circumference-adapted.Methods A total of 450 healthy subjects who underwent chest CT scan were enrolled.According to the size of the chest circumference(cm),they were divided into 3 groups(n=150):group A(<90 cm),group B(90-100 cm)and group C(>100 cm).Each group was randomly divided into 5 subgroups(n=30).The pre-ASIR-V ratio of each subgroup ranged from 0%to 80%,increasing at 20%intervals.Compare the differences in image quality and radiation dose between subgroups within different chest circumferences.The objective evaluation of image quality and radiation dose comparison was analyzed by one-way ANOVA,and the subjective scores were analyzed by Kruskal-Wallis H test.Results In group A,B and C,the image noise of each subgroup decreased slightly with the increase of pre-ASIR-V ratio;the CNR value of descending aorta increased slightly,and the highest was 60%ASIR-V.The difference was not statistically significant;the radiation dose between the groups gradually decreased,and the difference was statistically significant(P<0.000).In the same chest area,the overall score of the image quality of the lung window and the mediastinal window began to decrease when the front 60%ASIR-V,group A and group B,the longitudinal window value of the front 80%ASIR-V was lower than the rest.The difference between the two groups was statistically significant(P<0.05).The scores of the lung window and mediastinal window of the 80%ASIR-V subgroup were less than 3 points,which affected the diagnosis and was statistically different from the other subgroups.P<0.05).Conclusion The chest CT low-dose scan selects the optimal pre-ASIR-V weight ratio according to the examiner’s chest size,which can reduce the radiation dose while ensuring image quality.(When the chest circumference is less than 100 cm,it is recommended to use the front 80%ASIR-V reconstruction;when the chest circumference exceeds 100 cm,it is recommended to use the front 60%ASIR-V reconstruction).