目的 采用回顾性心电门控模拟前瞻性心电门控冠状动脉CT 成像(CCTA),探讨前瞻性心电门控CCTA 在中等心率病人中的可行性.方法 本研究共纳入63 例病人[心率(HR)为65～75 次/min,心率变异性(HRv)＜5次/min,钙化积分＜400 分]行回顾性心电门控CCTA,扫描结束后以R-R 间期60%的相位为中心,按400 ms 占据曝光平均心率R-R 间期的比例以5%的间隔重建期相,以冠状动脉节段为单位,对所有重建的图像进行评分(5 分制:5分为优,1 分为差),以统计描述可用于诊断的冠状动脉节段数目所占比例评价前瞻性心电门控CCTA 在中等心率病人中的应用价值.结果 共有822 个冠状动脉节段参与评分,平均得分4.15±0.72,可用于诊断的冠状动脉节段数目比例为97.76%.结论 中等心率下前瞻性心电门控技术可通过预设60%采集期相,重叠时间设置为200 ms 可以重建出满足诊断的图像,且理论上可以大幅降低辐射剂量.%Objective To evaluate robustness of coronary artery computed tomographic (CT) angiography withprospectively gated axial (PGA) CT technique at intermediate heart rate (65~75 beats per minute) using retrospectively gatedhelical (RGH) CT technique in 64-slice spiral CT. Methods 63 consecutive patients with heart rates (HR) of 65 to 75 bpm,heart rate variability of below 5 bpm underwent CT angiography with RGH technique (tube voltage was 120 kV and tubecurrent tailored to BMI). The 5% acquired data during each intermediate temporal window in the R-R interval were used toreconstruct images. The intermediate temporal window was 400 ms in the R-R interval at current mean HR, and the centre ofthe temporal window was 60%. All coronary artery segments were evaluated for image quality with 5-point scale. The meanimage quality score and the percentage of assessable coronary artery segments were used to evaluate diagnostic value on theselected temporal window. Results 822 coronary artery segments were depicted and were evaluated. The mean imagequality score was 4.15 ±0.72. The percentage of assessable coronary artery segments was 97.76% . Conclusion PGAcoronary CT angiography with proper revise image acquisition phase and padding time could offer assessable image quality atintermediate HR.
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