基于体重指数调整的儿童上腹部低剂量CT扫描研究

Application of Different Body Mass Index Adjustment in the Low-dose CT Scan of Upper Abdomen in Children

目的:研究基于体重指数调整的儿童上腹部低剂量CT扫描方案的辐射剂量、主客观图像质量和诊断准确性。方法:对比分析不同体重指数儿童上腹部低剂量CT扫描中的差异,前瞻性分析50%自适应统计迭代重建(adaptive statistical iterative reconstruction,ASIR)常规剂量和基于体重指数调整的上腹部低剂量CT扫描方案检查,年龄1个月~14岁。使用五点量表主观评估包括噪音,清晰度,伪影和诊断可接受性在内的图像质量。结果:3名医师对图像质量主观评分的一致性大,差异无统计学意义(κ=0.76,P>0.01)。各组肝实质CT值比较差异无统计学意义(P>0.01);各组间SNR比较差异有统计学意义(P<0.01),图像质量均可接受。基于体重指数调整的上腹部B组所有辐射剂量参数均显著较低(P<0.01),其中A组正常高于B组正常,差异有统计学意义(P<0.01),后者剂量减少32.5%;A组超重高于B组超重,差异有统计学意义(P<0.01),后者剂量减少40.4%。结论:在正常体重和超重儿童中,50%ASIR重建的个性化低剂量CT扫描方案平均剂量明显低于常规剂量,而不会显著影响儿童上腹部CT检查的诊断图像质量。

Objective:To evaluate the feasibility of the radiation dose,subjective and objective image quality and diagnostic accuracy of the low-dose CT scanning scheme for the upper abdomen of children based on BMI adjustment.Method:The differences in low-dose CT scans of the upper abdomen of children with different BMI were compared,and the 50%routine adaptive statistical iterative reconstruction(ASIR)and low-dose CT scan protocol based on BMI were prospectively analyzed,ranging in age from 1 month to 14 years old.A five-point scale was used to evaluate the subjective image quality including noise,sharpness,artifact,and diagnostic acceptability.Result:Inter-observer agreement among the three radiologists was sufficient,no significant statistical difference was existed among each group(κ=0.76,P>0.01).There was no significant difference of CT values of liver parenchyma among each groups(P>0.01).The differences of SNR among each groups were statistically significant(P<0.01).The image quality in each group were acceptable.All radiation dose parameters were significantly reduced in the group B based on BMI(P<0.01).Normal weight in group A was higher than that in group B,and the differences between two groups were statistically significant(P<0.01);and the dose of the normal weight children in group B was reduced by 32.5%.Overweight in group A was higher than that in group B,and the differences between two groups were statistically significant(P<0.01),and the dose of the overweight children in group B was reduced by 40.4%.Conclusion:In normal weight and overweight children,50%of the personalized low-dose CT scan regimen with ASIR reconstruction was significantly lower than the routine dose,without significantly affecting the diagnostic image quality of the upper abdominal CT examination in children.