Individual Scanning for Multislice Spiral CT Coronary Angiography

Objective To evaluate a method to adjust scan parameters individually for reducing radiation dose of multislice CT coronary angiography.Methods There were 131 cases divided into conventional group(group A) and low dose group(group B) with 61 patients in group A and 70 patients in group B.Standard scan technique was used in group A and dose reduction techniques were employed in group B.Subsequently,group B were scanned with individually adjusted mA and kV according to BMI.CTDIvol,DLP,ED,SNR and CNR in the two groups were evaluated.Results The average age of both groups of patients,heart rate,scan length,height,weight and BMI were no differences(P0.05).The average CTDIvol in group A and group B was(40.7±6.7) mGy and(24.5±10.8) mGy,respectively.There was a statistical difference in CTDIvol between the two groups(t=10.1,P0.05).Effective dose(ED) was(9.5± 1.6) mSv,(5.5±2.6) mSv,respectively.There was a statistical difference in ED between the two groups(t =10.0,P0.05).The radiation dose of group B was lower by 45% than that of group A.SNR was 38.9±10.5 and 36.0±12.2 respectively,with t=1.5 and P0.05;CNR was 35.0±9.7and 32.2±11.0 respectively,with t=1.6 and P0.05;there were no differences in SNR and CNR between the two groups.Conclusion Adjusting scanning parameters according to body mass index and heart rate for multislice CT coronary angiography can reduce the radiation dose while having no influence on the quality of imaging.