Triple-Rule-Out Computed Tomographic Angiography with Prospective ECG Gating: A Clinical Study in Chest Pain Patients with Heart Rate Lower Than 75 bpm

Objective To analyze the value of triple-rule-out(TRO) computed tomographic angiography in chest pain patients with heart rate lower than 75bpm.Methods Eighty night patients with chest pain were randomly divided into A and B groups: Group A(n=45) performed prospectively gated axial scan(PGA) and Group B(n=44) performed retrospectively gated helical scan(RGH).The tube voltage was 120kV and tube current tailored to BMI.Image acquisition was performed at 75%/60% of the RR interval,and the padding time setting was 100 ms/200 ms tailored to HR in group A,ECG modulation,full mA on 35%-85% of the R-R interval and low mA on rest of phases were used in group B.The image quality and radiation dose were compared between two groups.Results The mean effective dose for group A was 8.08 mSv,which represented a 65% reduction compared with that for group B(mean,23.65 mSv;t=-11.729,P0.00001).The mean coronary artery segments score was 4.58 for group A and 4.37 for group B(Z=-0.704,P=0.481).Conclusion TRO CT angiography using PGA technique could offer high image quality and reduced effective radiation dose compared with traditional RGH technique at low intermediate HR.