Study On The Basic Experiment And Clinical Application Of Low Dose Abdominal CT Scan In Children

Objective: To explore the adaptive statistical iterative reconstruction-V in CT scanning of children’s abdomen,and provide reference for optimizeing combination of pre-and post-ASi R-V percentage in children’s abdominal CT scan.Materials and Methods: 1.After the piglet was anesthetized,the piglet was supine on the examination bed,and the abdomen was scanned with 0%,20%,40%,60%,80%and 100% pre-ASi R-V,respectively.After the abdominal plain scan,piglets were enhancement scanned with 100%,80%,60%,40%,20% and 0% pre-ASi R-V.A total of 12 sets of images were obtained.12 groups of images were reconstructed by adding ASi R-V.A total of 42 sets of images were obtained.The image quality of 42 groups was evaluated by 2 senior radiologists using a blind method and a 5-point scale.CT values,noises,subjective scores,and radiation doses of unenhanced and enhanced abdominal tissues were analyzed respectively,and the data between each group were statistically analyzed.Based on the results of image quality and radiation dose,an appropriate pre-and post-ASi R-V percentage scheme was selected.2.According to the results of the basic experiment,10 children who received GE Revolution 256-slice CT scan for plain and enhanced abdominal CT scan from October2019 to January 2020 were prospectively collected and scanned with appropriate preand post-ASi R-V percentage.Ten cases of children who underwent GE Revolution256-slice CT scan from August 2018 to August 2019 for plain and enhanced abdominal.CT scan were retrospectively collected.A retrospective study was conducted to collect10 cases of children who underwent GE Discovery HD750 64-slice energy spectrum CT scan between August 2018 and August 2019 for abdominal plain and enhanced CT scan.Three groups of children’s abdominal plain scan and three stage enhanced image quality evaluation,using a 5-point scoring system,the three groups of subjective score for statistical analysis.Results: 1.With the increase of pre-ASi R-V,the radiation dose in piglets gradually decreased(P<0.05).In the same pre-ASi R-V group and with the increase of post-ASi R-V,SD values was gradually decreased,and the CNR values did not change or increased.In plain scan images,the subjective score of the images with 40%pre-ASi R-V combined 60% post-ASi R-V was similar to 0% pre-ASi R-V combined60% post-ASi R-V,and the radiation dose was reduced by 31.61%.In the enhanced images,the subjective score of the images with 60% pre-ASi R-V combined 60%post-ASi R-V was similar to 0% pre-ASi R-V combined 60% post-ASi R-V,and the radiation dose was reduced by 48.9%.2.40% pre-ASi R-V combined 60% post-ASi R-V was used for plain CT scan of children’s abdomen,and 60% pre-ASi R-V combined with 60% post-ASi R-V was used for enhanced CT scan of children’s abdomen,with good image quality and no influence on diagnosis.Compared with the retrospective collection of CT images of the abdomen of children reconstructed with 40% pre-ASi R-V combined with 40% post-ASi R-V,the subjective score was similar(P>0.05).Compared with the retrospectively collected CT images of children’s abdomen reconstructed with FBP,the subjective score was higher and the difference was statistically significant(P<0.05).Conclusion: ASi R-V can significantly reduced the radiation dose without affecting image quality,it is recommended to use 40% pre-ASi R-V combined with 60%post-ASi R-V for children’s abdominal CT plain scan,and 60% pre-ASi R-V combined with 60% post-ASi R-V for children’s abdominal CT enhanced scan,which is beneficial to theoretically reduce the damage of radiation dose.