The comparison among image qualities of CTA at different dose in both lower extremity artery / 中华放射医学与防护杂志

ABSTRACT

Objective To explore the differences among CT angiography(CTA) at different doses in both lower extremity arteries,and the relationship among volume rendering(VR) image quality,CT number and standard deviation(SD) value.Method CTA in lower extremity artery was performed in 90 patients.The participants were randomly divided into three groups,including a routine group (120 kV,150 mAs),120 kV and 80 mAs group,and 100 kV and 130 mAs group with 30 cases in each group.The images were processed with VR and classified into three degrees,the first class,the second class and the third class,and VR image quality levels of three groups were compared.The receiver operating characteristic curve(ROC) was used to analyze the correlation among VR image quality level,CT number and SD value.Results The percentage of VR image level at the first class was 93.3％ in the routine group,86.6％ in the 120 kV and 80 mAs group and 96.6％ in the 100 kV and 130 mAs group.According to the correlation analysis between the SD value and VR image quality of CTA in lower extremity artery,the area under curve in ROC analysis was 0.9078.According to the correlation analysis between the CT number and VR image quality of CTA in lower extremity artery,the area under curve in ROC analysis was 0.9116.Conclusions The low-dose CAT in lower extremity artery is feasible.Application of 100 kV and 130 mAs could ensure better image quality.