绝对时相收缩期采集降低心房颤动患者冠状动脉CT成像辐射剂量的研究

Absolute phase acquisition versus relative phase acquisition for dual source CT coronary angiography in patients with atrial fibrillation

目的：研究绝对时相收缩期采集在心房颤动患者冠状动脉CT血管造影（CTA）的可行性,并与相对时相采集对照.方法：连续入组92例持续心房颤动患者,其中A组46例采用绝对时相收缩期采集（R波后200～400ms）,B组46例采用相对时相收缩期采集（R-R间期：30％ ～ 50％）.对两组扫描的冠状动脉分别做图像处理.比较两组的图像质量和辐射剂量.结果：A组冠状动脉段图像质量总体评分为（1.56±0.25）,B组为（1.62±0.28）,两组间差异无统计学意义（P =0.283）.两组之间可诊断的冠状动脉段比率差异无统计学意义（P =0.785）.A组有效剂量5.76（3.20,8.63） mSv;B组有效剂量9.27（4.74,12.65）mSv,两组间有效剂量差异有统计学意义（P =0.001）.绝对时相采集比相对时相采集降低辐射剂量约38％.结论：在心房颤动患者绝对时相收缩期采集具有可行性,该方案比相对时相采集显著降低辐射剂量,而不影响图像质量.

Objective：To investigate the feasibility of absolute phase systolic acquisition for coronary CT angiography （CCTA） in patients with atrial fibrillation （AF） with comparison to relative phase acquisition.Methods：Ninety-two patients with persistent AF were enrolled in the study,46 patients were scanned with absolute phase systolic acquisition （200-400 ms after the R wave） and another 46 were studied by relative phase systolic acquisition （30％-50％ of the R-R interval） for CCTA using the second generation dual source CT （DS-CT）.The imaging quality and radiation dose were compared between the two protocols.Results：There was no significant difference in overall image quality between the two groups （P =0.283）.Median effective doses of absolute phase acquisition and relative phase acquisition were 5.76 （3.20,8.63） mSv and 9.27 （4.74,12.65） mSv respectively （P =0.001）,showing that absolute phase acquisition reduced radiation dose by 38％ compared with that of relative phase acquisition.Conclusion：In patients with AF,absolute phase systolic acquisition is feasible in DS-CT coronary angiography,and can decrease radiation exposure by approximately 35％ compared with relative phase acquisition,while preserving image quality.