目的通过比较64排螺旋CT前瞻 性心电门控与回顾性心电门控冠状动脉 成像的图像质量和辐射剂量，探讨前瞻 性心电门控冠状动脉成像技术在降低辐 射剂量中的作用。资料与方法 157例疑 似冠状动脉疾病的患者随机分为两组， 前瞻性心电门控组85例和回顾性心电门 控组72例，两组心率均＜65次/min，记 录两组的成像质量和辐射剂量，并进 行统计学分析。结果 前瞻性心电门控 组有效辐射剂量(4.42±1.52)mSv明显 低于回顾性心电门控组(14.84±3.98) mSv(P<0.01)，差异有统计学意义；前瞻 性心电门控和回顾性心电门控两组冠状 动脉成像质量评价差异无统计学意义(P ＞0.05)，且前瞻性心电门控组图像优秀 率略高于回顾性心电门控组。结论 在较 低且平稳的心率(≤65次/min)条件下， 采用64排螺旋CT前瞻性心电门控技术即 能有效降低辐射剂量，又能保证临床诊 断所需的冠状动脉图像质量。

Objective To explore the role of prospective ECG-gated coronary angiography in reducing radiation dose by comparing image quality and radiation dose of prospective and retrospective ECG-gated 64-row CT coronary angiography. Materials and Methods 157 patients suspected coronary artery disease were divided in two groups. 85 patients were taken prospective ECG gating axial scan and 72 were taken retrospective ECG gating helical scan.The heart rate was ﹤65bmp.Coronary artery segments were assessed for imaging quality and radiation dose values were calculated. Results Effective radiation dose of prospective ECG gating group (4.42±1.52mSv) was significantly lower than that of retrospective ECG gating group (14.84±3.98mSv)(P<0. 01). There was no significant difference in image quality between two groups(P﹥0.05),and image excellent rates of prospective ECG gating group was higher than that of retrospective ECG gating group. Conclusion Prospective ECG gating axial scan effectively reduces the radiation dose and receives similar image quality compared with retrospective ECG gating coronary angiography in patients with heart rates ﹤65bpm.