Abstract：Objective: To compare image quality, diagnostic accuracy and radiation dose of prospective and retrospective electro-cardiogram(ECG) gated dual-source computed tomography(DSCT). Methods: One hundred patients who underwent DS-CT coronary angiography(DS-CTCA) were enrolled in the study, 60 were scanned by prospective scan and another 60 were analyzed by gated CT scan retrospectively. Sixty patients were divided into two groups according to their heart rate, receiving either step-and-shoot(heart rate less than 70bpm) or adaptive sequential(more than 70bpm) ECG gated DSCT separately. Retrospective CT angiography was performed with DSCT in another sixty patients, which were divided into two groups according to their heart rates too. The imaging quality of coronary artery segments in the four groups was evaluated using a four-point grading scale by two independent reviewers. Patient radiation dose was calculated by multiplying dose length product by conversion coefficient of 0.017. Results: There was no significant difference between the two groups for age, BMI, heart rate, heart rate variability and image noise. Of the 2801 coronary segments scored, excellent or good image quality(score of 1 or 2) was achieved 95.9%(702/732), 83.8%(547/653), 97.1%(720/742), 86.9%(586/674), and with no significant differences for A and C, B and D groups(P＞0.05). Effective doses of prospective and retrospective gated scan were (3.28±0.23)mSv, (5.49±1.31)mSv, with an average of (4.35±1.44)mSv, and (15.29±0.55)mSv, (13.44±1.11)mSv, with an average of (14.51±1.32)mSv, respectively, and decreased 78.55%, 59.16%, with an average reduction of about 70.03%, respectively(P<0.001). In prospective gated group, there was statistically significant between high heart rate and low heart rate. Conclusion: Prospective gated DSCT scanning can provide adequate coronary diagnostic information, while significantly reduce the radiation dose. It can be used for suspected coronary artery disease screening.
2011, Vol. 22 
