A Preliminary Study Of High-pitch Dual-source CT Coronary Angiography Using Flash Spiral Mode In Low-kilovoltage Setting

Objective:To evaluate the feasibility of low tube voltage techniques in high-pitch dual-source CT coronary angiography using flash spiral mode in patients with a large range of body mass index(BMI). Methods:90consecutive patients (M/F57/33)underwent CTCA using flash spiral mode were enrolled into this study. Who were divided by BMI firstly, group A:n=41, BMI≤25kg/m2; group B:n=49,25kg/m2<BMI≤30kg/m2. Then they were divided into conventional voltage group and low tube voltage group, group Al: n=27,100kVp,group A2:n=14,120kVp;group B1:n=26,100kVp, group B2:n=23,120kVp.18patients underwent Coronary angiography(CAG) among group B1. The image quality score, Noise, Signal-to-noise Ratio(SNR),Contrast-to-noise Ratio(CNR),CT dose index volume(CTDIvoi), Dose length product (DLP)and Effective dose(ED)were compared between group Al and A2, B1and B2; The diagnostic accuracy of CTCA was calculated with CAG as reference standard. Result:(1)The non-diagnostic coronary artery segments were:group Al9.4%(28/297); group A28.2%(13/159); group B18.0%(23/286); groupB28.3%(21/254).(2)The image quality:There was significant difference in Noise among group A1and A2(P=0.000), The noise of group A1was higher than A2; There was significant difference in Noise among group B1and B2(P=0.000),The noise of group B1was higher than B2; however, there was no significant difference in image quality score, SNR and CNR among them(P>0.05).(3)Radiation dose:There was significant difference in CTDIvol, DLP and ED among group Al and A2(P=0.000).The average effective radiation dose of group Al was decreased48.17%compared with A2;There was significant difference in CTDIvol, DLP and ED among group B1and B2(P=0.000),The average effective radiation dose of group B1was decreased15.81%compared with B2. (4)Diagnostic accuracy:The diagnostic rate was90.53%(86/95). Conclusion:The low tube voltage techniques in high-pitch dual-source CT coronary angiography using flash spiral mode is feasible for patients with a large range of body mass index(25kg/m2<BMI≤30kg/m2).