Comparative study of prospective and retrospective electrocardiogram gated dual-source computed tomography coronary angiography

Objective:To compare the image quality and radiation dose values of prospectine and retrospective electrocardiogram(ECG) Gated dual-source computed tomography coronary angiography(CTCA).Methods:A total of one hundred and ten patients referred for coronary dual-source CT angiography were randomly divided into 2 groups: group A(60 cases)using prospective ECG-triggering sequence scan mode and group B(50 cases)using retrospective ECG-gating helical scan.Inclusion criteria included heart rate ≤75 bpm,and heart rate variability ≤10 bpm.Patients with a body mass index(BMI) ≥25 kg/m2 were examined with a tube voltage of 120 kV,whereas,BMI﹤25 kg/m2 were examined with 100 kV.The radiation dose was recorded and the image quality was blindly evaluated.The image quality and radiation dose were compared with Wilcoxon rank sum test and t-test between the two groups respectively.Results:The mean score of image quality in group A was(3.74±0.51) and that in group B was(3.68±0.58).There was no significant difference in image quality between the two groups(Z=-1.891,P=0.059).Mean estimated radiation dose of group A,B was(2.38±0.83),(9.49±3.38) mSv,respectively.There was a significant difference between the two groups(t=-14.522,P﹤0.001),and the radiation dose of group A was reduced by 75%.Conclusion:In patients with low and stable heart rates,the sequential scan technique is a promising method to effectively reduce radiation exposure and to maintain diagnostic image quality on dual-source CT.