Optimized combination of pre-and post-adaptive statistical iterative reconstruction-V in low dose abdominal CT scanning / 中国医学影像技术

ABSTRACT

Objective To observe the impact of adaptive statistical iterative reconstruction-V (ASiR-V) on image quality and radiation dose in abdominal CT imaging,and to optimize combination of pre-and post ASiR-V percentage.Methods Totally 160 patients underwent plain and contrast-enhanced abdominal CT were randomly divided into study group or control group (each n=80).In study group,plain images were reconstructed with 20％ pre ASiR-V combined with 20％,40％,60％ and 80％ post-ASiR-V,the arterial phase images were reconstructed with 40％ pre-ASiR V combined with 40％,60％ and 80％ post-ASiR-V,while the venous phase images with 60％ pre-ASiR-V combined with 60％ and 80％ post-ASiR-V,and the delayed phase images with 80％ pre-ASiR-V combined 80％ post-ASiR-V.In control group,images were reconstructed with filtered back projection (FBP) and 0 pre-ASiR-V combined post-ASiR-V (20％ in plain,40％ in arterial phase,60％ in venous phase and 80％ in delayed phase imaing).The objective parameters (image noise [SD] and CNR) and image quality scores were analyzed and compared.Results CT dose index,dose length product and effective dose of each phase in study group were lower than those in control group (all P＜0.001).In study group,with the increasing of post-ASiR-V percentage,SD values gradually decreased (P＜0.01),and CNR gradually increased or did not change.With the increasing of post-ASiR-V (20％-60％),image quality scores increased,and image quality of 80 ％ post-ASiR-V was low.In study group,image quality of 20％ pre-ASiR-V combined 40％ or 60％ post-ASiR-V was similar to 20％ post-ASiR-V image in control group in plain,and that of 40％ pre-ASiR-V combined 60％ post-ASiR-V was similar to 40％ post-ASiR-V image in control group in arterial phase (all P＞0.05),while image quality scores of other combinations of pre-and post-ASiR-V percentages were lower than those in control group.Conclusion ASiR-V can improve abdominal CT image quality,and 40％ pre-ASiR-V combined 60％ post-ASiR V is recommended.