Image quality and required radiation dose for coronary computed tomography angiography using an automatic tube potential selection technique.

Abstract

To investigate the image quality and the minimum required radiation dose for automatic tube potential selection (ATPS) in dual-source computed tomography (DSCT) coronary computed tomography angiography (CCTA). Three hundred twenty-five consecutive patients (153 men and 172 women) undergoing CCTA were assigned to either the ATPS group (n=172) or the control group (n=153); the control group underwent imaging at a constant current of 120kV. All patients were scanned in either prospectively ECG-triggered high-pitch helical mode or sequential mode. The subjective image quality score, attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), volume CT dose index (CTDIvol), and effective dose (ED) were compared between the two groups with the Student t test or Mann-Whitney U test. The subjective image quality score was not significantly different between the two groups. Imaging noise and attenuation were both significantly higher in the ATPS group than in the control group (imaging noise: 25.6±7.6 versus 15.8±4.0HU, P<0.001; attenuation: 559.6±142.0 versus 412.5±64.3HU, P<0.001). SNR and CNR were significantly lower in the ATPS group than in the control group (SNR: 23.21±7.40 versus 27.71±8.25, P<0.001; CNR: 27.81±8.44 versus 33.94±9.69, P<0.001). ED was significantly lower in the ATPS group than in the control group (ED: 1.25±1.24 versus 2.19±1.77mSv, P<0.001). For both groups, ED was significantly lower in the high-pitch mode than in the sequential mode. The use of ATPS for CCTA significantly reduced the radiation dose while maintaining image quality.