Abstract: Objective To assess the image quality and effective radiation dose of prospectively electrocardiogram -gated high-pitch spiral acquisition mode(flash mode)of coronary venous system angiography as compared with retrospectively ECG-gated spiral acquisition mode. Methods A total of 74 patients undergoing MSCT in our hospital from September 2013 to September 2014 were divided into two groups according to the scanning mode at random, named FLASH group(flash spiral mode, n=39)and RGH group(retrospective ECG-gated spiral acquisition mode, n=35).The image quality scores, contrast-to-noise ratio(CNR), effective radiation dose and influencing factors on image quality between the two groups were assessed.The image quality and radiation dose of patients in two subgroups(heart rate＜65 /min or ≥65 /min)were compared. Results Characteristics and scan parameters of patients in two groups had no significant difference.There were no significant differences in image quality scores and contrast-to-noise ratio between two groups image quality scores: 3.3±1.3(FLASH group)vs 3.2±1.2(RGH group), P＞ 0.05; CNR: 7.0±3.2(FLASH group)vs 7.5±3.2(RGH group), P＞ 0.05.Furthermore, the average image quality scores and mean CNR were similar between FLASH group and RGH group in spite of heart rate＜65 /min or≥65 /min.The estimated radiation dose was(0.8±0.2)mSv in FLASH group and(7.2±2.7)mSv in RGH group(P＜0.001). Conclusion Prospectively electrocardiogram-gated high-pitch spiral acquisition mode provides a similar image quality to the retrospectively ECG-gated spiral acquisition mode, with significant reduction of radiation exposure.