The feasibility analysis of coronary computed tomography angiography with low tube voltage and low iodine concentra-tion contrast

JIA Yanrong; ZHANG Haoliang; XU Yandong; LIU Zhijun; QI Lixia; DU Hai; LIU Hui; GENG Mingming

Abstract：Objective To investigate the feasibility of using low tube voltage and low iodine concentration contrast ( Dual Low) CT scan techniques in Coronary CTA ( CCTA) .Methods 170 patients undergoing CCTA with BMI<28 kg/m2 were di-vided into two groups randomly.Group A (85 patients) was the dual-low group, which was scanned with tube voltage of 100 kVp, tube current of 500 mAs and injected with iso-osmolarity contrast agent Visipaque 270(270 mgI/ml) with ASiR 40%reconstruc-tion.Group B (85 patients) was the control group, which was scanned with tube voltage of 120 kVp, tubecurrent of 500 mAs and injected with low-osmolarity contrast agent Omnipaque 350(350 mgI/ml) with FBP reconstruction.Both groups were scanned with perspective cardiac gating, after scanning the images transmited to the workstation for reprocessing.The images were assessed sub-jectively by two experienced radiologists with double-blindly.Objective assess was five ROIs that were placed onto the ascending root of Aorta (AO), Left Main Artery (LM), Left Anterior Descending (LAD), Left Circumflex Artery (LCX), Right Coronary Artery ( RCA) , and the image qualities were evaluated objectively using CT values, noise, Signal Noise Ratio ( SNR) , Contrast Noise Ratio ( CNR) .The radiation dosages ( CTDIvol, DLP and ED) and iodine intake were also recorded and compared.Statis-tics were used two independent samples paired t-test and nonparametric test, P <0.05 considered the difference was statistically significant.Results On radiation dose, CTDIvol, DLP, ED and iodine intake of group A (Dual Low) were obviously lower than Group B ( P <0.05).The image qualities of the two groups were not significantly different, the subjective assess of group A was superior to the group B.On Objective assess, the half of indexs ( 10 ) of the image quality was improved significantly ( P <0.05) , especially the CT value, in five parts, were all have improved significantly.In addition, in group A, multiple correlation analysis of the CNR and SNR was significantly negative correlation with BMI( P <0.05), while in the group B, we can't think there was acorrelation between them.Conclusion Cardiac CTA examination of using lower tube voltage 100 KVP, low concentra-tion contrast 270 mgI/ml with ASiR 40%can not only obtain good image, but also reduce the radiation dose and iodine intake sig-nificantly.