An optimized radiation dose on dual-source CT coronary angiography

Objective:To evaluate the image quality and radiation dose of dual-source CT coronary angiography(CTCA)with a more narrow exposure window.Methods:In all,360 cases underwent dual-source CTCA and were randomly divided into five groups according to the heart rate and scanning protocol.Group A,retrospective ECG-gated scan of the patients with heart rate65beats per minute(bpm)was performed from 70% to 80% of the R-R interval to reconstruct coronary artery;Group B,prospective ECG-gated scan of the patients with heart rate65bpm was performed with 1% of the total length of the exposure window;Group C,retrospective ECG-gated scan of the patients with heart rate≥65bpm was performed from 30% to 80% of the R-R interval to reconstruct coronary artery;Group D,prospective ECG-gated scan of the patients with heart rate≥65bpm was performed with 10%exposure window;Group E,low dose retrospective ECG-gated scan of the patients with heart rate≥65bpm was performed.The average effective radiation dose and image quality of coronary arteries(4-point scale)were calculated for each group,and statistical analysis was done.Results:Difference of radiation dose between each group was statistically significant(P0.05).A narrowed scan window on prospective ECG gated dual-source CTCA could reduce the radiation dose;while there was no significant difference in the image quality between the groups(P0.05).Conclusion:Prospective ECG-gated dual-source CTCA can reduce the radiation dose while maintaining good image quality by selecting 1% of the total length of the exposure window(heart rate65bpm),and 10% of the total length of the exposure window(heart rate≥65bpm)after obtaining the optimal interval by plain scan.