Lean body wight dose determined contrast injection protocol in spectral CT of colorectal cancer
Objective To observe the impact of lean body weight(LBW)dose determined contrast injection protocol on imaging quality of contrast enhanced spectral CT for dispalying colorectal cancer,and to select the optimal scanning energy level.Methods Totally 150 patients with suspected colorectal tumors were prospectively enrolled and randomly divided into total body weight(TBW)group(group A),500LBW group(group B)and 400LBW group(group C)(each n=50).Contrast-enhanced abdominal spectral CT images were acquired with contrast medium of 500 mgI/kg(TBW),500 mgI/kg(LBW)or 400 mgI/kg(LBW)in group A,B and C,respectively,and then 2-phase iodine-based material decomposition images were reconstructed.Images in group A and B were reconstructed at 70 keV,while in group C was reconstructed 40-70 keV(with 10 keV interval)(C40-70 kev subgroups).CT values of arterial phase superior mesenteric artery(SMA)and inferior mesenteric artery(IMA),as well as of liver in venous phase were measured.Then signal-to-noise ratio,contrast-to-noise ratio and liver enhanced CT value(△HU)were calculated,and imaging qualities were comparatively analyzed.Results Compared with group A,the contrast media doses of B group and C group decreased by 23.00％and 37.19％,respectively(both P＜0.05).During arterial phase,CT values of SMA and IMA in group A,B and C40-60keV subgroups images were all over 350 HU.The variation rate of CT value of SMA and IMA in group A was 9.42％and 9.32％,while in C60 keV was 9.82％and 10.09％,respectively,all lower than those in group A(all P＜0.05).During venous phase,△HU in images of group A,B and C40-60 kev subgroups were all over 50 HU.The variation rate of △HU in group B and C60 keV was 8.60％and 8.67％,respectively,both lower than in group A(both P＜0.05).No significant difference of arterial nor venous phases normalized iodine concentration was found among 3 groups(both P＞0.05).In group C,C60 keV subgroup had the highest subjective scores in both arterial and venous phases,which were not significantly different with those in group A(both P＞0.05),while subjective scores of other subgroups were lower than that in group A(all P＜0.05).Conclusion Low contrast injection protocol based on LBW combined with spectral CT could provide high quality images and reducing dose of contrast media.60 keV was the most recommended level for scanning.
colorectal neoplasmstomography,X-ray computedprospective studieslean body weight
万方数据
维普
