The effect of chest circumference index adjusting tube voltages technique on image quality and radiation dose at coronary CT angiography / 中华放射学杂志

ABSTRACT

Objective To explore the effect of chest circumference index adjusting tube voltage techniquey on image quality and radiation dose at coronary CTA. Methods One hundred and twenty consecutive patients [body mass index(BMI)90 cm, n=20). All patients were examined by coronary CTA. The patients in conventional group were performed using retrospective ECG-gating technology and reconstructed by filtered back projection algorithm. The tube voltage/tube current was 120 kV/1 000 mAs. Prospective ECG?gating technology and iterative algorithm reconstruction were used in low dose group. The tube voltages/currents were 80 kV/150 mAs, 100 kV/150 mAs, 120 kV/150 mAs in A, B, C group, respectively. Image quality was assessed by subjective evaluation (image quality score) and objective evaluation (signal?to?noise ratio).The effective radiation dose was calculated. Analyses of the differences between groups were compared with image quality, radiation dose by single factor variance and Wilcoxon signed ranks test.Results The image quality scores and signal?to?noise ratio of aorta were respectively (3.47 ± 0.38), (3.48 ± 0.27), (3.45 ± 0.32), (3.46±0.29) and (15.5±3.6), (15.8±3.6), (15.8±4.1), (16.2±3.9) in conventional, A, B and C groups, there was no statistical difference between the four groups (P=0.24, 0.43). The effective radiation dose of four groups were respectively (17.15 ± 3.25), (0.88 ± 0.02), (1.38 ± 0.05), (2.32 ± 0.04) mSv, the difference was statistically significant (P=0.02). The effective radiation dose of A, B, C group was significantly lower than that in the conventional group. Conclusion Chest circumference index adjusting tube voltages technology at coronary CT angiography can effectively reduce the effective radiation without compromise of image quality.