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目的:通过比较图像质量与辐射剂量,评价64层螺旋CT低剂量回顾性心电门控冠脉成像技术临床应用的可行性。方法:选取拟行CT冠状动脉造影的患者80例(心率小于65次/min,心率波动范围小于5次/min),所选患者分为两组,分别进行低剂量回顾性心电门控(40例,开启ECG管电流调制技术,70%～80%期相满电流输出)及常规回顾性心电门控(40例,35%～80%期相满电流输出)CT冠脉造影,依据患者体质量指数选择管电流(400～800 mA),管电压120 kV。比较两组的辐射剂量及图像质量。P<0.05认为差异具有统计学意义。结果:低剂量回顾门控组与常规回顾门控组图像质量差异无统计学意义(Z=-4.78,P=0.23)。低剂量回顾门控组CTCA辐射剂量平均(13.76±2.38)mSv,常规回顾门控组CTCA辐射剂量平均(20.06±3.35)mSv,差异有统计学意义(t=-8.39,P=0.00),使用低剂量回顾门控降低了31.4%的辐射剂量。结论:低心率患者行回顾门控CTCA通过修改ECG管电流调制技术参数得到的图像质量与常规回顾门控CTCA无差别,而辐射剂量显著减低。
OBJECTIVE: To evaluate the feasibility of low-dose retrospective ECG-gated coronary angiography with 64-slice spiral CT by comparing image quality with radiation dose. Methods: Totally 80 patients undergoing coronary angiography (heart rate less than 65 beats / min and heart rate fluctuation less than 5 beats / min) were enrolled in this study. The patients were divided into two groups and received low-dose retrospective ECG gating 40 cases, open ECG tube current modulation technology, 70% to 80% full phase current output) and conventional retrospective ECG gating (40 cases, 35% to 80% phase full current output) CT coronary angiography, based on Patient body mass index selected tube current (400 ~ 800 mA), tube voltage 120 kV. Radiation dose and image quality were compared between the two groups. P <0.05 considered that the difference was statistically significant. Results: There was no significant difference in image quality between low-dose gating group and conventional gating group (Z = -4.78, P = 0.23). The average dose of CTCA radiation in gated group was (13.76 ± 2.38) mSv and the average dose of CTCA radiation in gated group was 20.06 ± 3.35 mSv (t = -8.39, P = 0.00) Low dose review Gating reduced the radiation dose by 31.4%. CONCLUSIONS: Patients with low heart rate underwent retrospective gated CTCA. Image quality obtained by modifying the ECG tube current modulation technique was indistinguishable from conventional retrospective gated CTCA with significantly reduced radiation dose.