前瞻性心电触发轴位扫描技术在64层螺旋CT中的应用

目的探讨在64层螺旋CT冠状动脉成像中采用前瞻性心电触发轴位扫描技术的图像质量和辐射剂量。方法选择采用前瞻性心电触发轴位扫描技术进行64层螺旋CT冠状动脉成像的患者160例作为前瞻组。将相同扫描参数输入回顾性心电门控螺旋扫描程序,获得扫描剂量数据作为回顾组。由2名放射科医师分别进行图像重建和图像质量评价。冠状动脉图像质量分级采用4级评分法。结果 2名放射科医师在图像重建和图像质量评价方面均有良好的一致性。160例患者除8例图像有严重血管错层伪影、2例冠状动脉严重钙化,共显示1449个冠状动脉节段。1～3分以上的1431个节段(98.76%)具有较好的图像质量,可以满足临床诊断要求。前瞻组与回顾组的平均有效剂量差异有统计学意义(3.17±1.17)mSv vs (22.09±6.72)mSv,P0.01]。结论在64层螺旋CT冠状动脉成像中采用前瞻性心电触发轴位扫描技术可在保证图像质量的同时显著降低辐射剂量。

The application of prospective ECG-triggered axial scan technique to 64-row MDCT

Objective To explore the image quality and radiation dose of coronary CT angiography with prospective ECG-triggered axial scan protocol.Methods 160 patients who underwent prospective ECG-triggered coronary 64-MDCT angiography were chosen as prospective group.Before prospective CT scan,the retrospective ECG-gated protocol was loaded onto the computer to get the dose index of retrospective group.Two independent radiologists performed the image reconstruction and evaluated the image quality ( 1,excellent;4 ,poor) with the 17-segment American Heart Association classification model.Results Acceptable image quality ( scores 1 — 3 ) was achieved in 1431(98.76%) of 1449 coronary segments with prospective CT angiography.The mean effective doses of prospective group and retrospective group were respectively(3.17 ± 1.17) mSv and (22.09 ± 6.72) mSv,and the difference had statistical significance (P < 0.01).Conclusion In 64-row MDCT coronary angiography,with prospective ECG-triggered axial scan technique, the radiation dose can be greatly reduced compared with retrospective ECG-gated coronary 64-row MDCT angiography,while acceptable image quality can be obtained.