RESUMO
Objective To investigate the clinical feasibility of spectral monochromatic imaging combined with adaptive statistical iterative reconstruction-V (ASIR-V) in upper abdominal enhanced scanning with double-low technique for severe liver cirrhosis.Methods Totally 126 cases performed abdominal contrast-enhanced CT scanning were collected prospectively and assigned to 3 groups with 42 cases in each group with random number table method.The filtered back projection algarithm,120 kV and contrast agent dose of 420 mgI/kg were used for the cases of control group.The cases for spectral group and combined group were scanned with spectral imaging mode and contrast agent dose of 300 mgI/kg.The 60 keV monochromatic images combined with pre-0％ and post-40％ ASIR-V were selected and analyzed for spectral group.Combined group with pre-40％ ASIR-V was divided into 2 subgroups with 50 keV,post -50％ ASIR-V and 60 keV,post-40％ ASIR-V separately.One-way ANOVA test was used for analysis of radiation dose and quantitative parameters,and Rank sum test was used for image subject evaluation.Results The CT numbers and CNR had significant differences among spectral group,combined group and control group(F=4.293-13.134,P＜0.05) except for the images of liver parenchyma in PVP and that of 50 keV combined 50％ASIR-V group were higher than that of control group (q=1.825-3.736,P＜0.05).No significant differences existed for image noise and overall image quality scores of organs in four groups.The visualization of hepatic vascular branches in 50 keV combined 50％ASIR-V group was higher than that of other three groups(Z=2.793-6.328,P＜0.05).The radiation dose of combined group was lower than that of spectral and control group (q =-4.879--2.531,P ＜ 0.001).Conclusions Spectral monochromatic imaging combined with pre-and post-ASIR-V can reduce contrast agent dose and radiation dose without degrading image quality for the severe liver cirrhosis in upper abdominal enhanced scanning.