目的 评价应用变速扫描克服多扇区重建算法引起的心率与球管旋转速度之间的谐振现象的可行性.方法 回顾性选择66例接受螺旋CT冠状动脉造影的患者,当心动周期与球管旋转周期比值为2:1与3:2时形成谐振点,为谐振组,共16例;其余50例为非谐振组.比较两组的冠状动脉成像质量.结果 谐振组大部分图像质量评分为3级.非谐振组与谐振组心率相同、但选择不同球管旋转速度者图像质量评分全部为1级,差异有统计学意义(G=36.07,P＜0.01).非谐振组50例,共显示540支血管,可用于评估的冠状动脉分支515支,占95.37%(515/540).结论 通过变速扫描.可消除心率与球管旋转速度呈谐振状态而对图像质量造成的不利影响,提高冠状动脉图像质量.%Objective To observe the feasibility of using variable gantry rotations on conquering the harmonic of heart rate and gantry rotation caused by multi-sector reconstruction algorithm during multislice spiral CT coronary angiography (MSCTCA). Methods Sixty-six patients undergoing MSCTCA with 64-slice spiral CT were enrolled. According to the relations of cardiac cycle and gantry rotations, the patients were divided into two groups, i.e. synchronous group (ratio 2:1,3:2, n=16) and asynchronous group (n=50). Imaging qualities of the two groups were compared. Results In synchronous group, the scores of most images were 3. When gantry rotation was changed, all the scores were 1 in patients with the same range of heart rate in difference groups (G=36. 07, P＜0. 01). Of the 50 patients in asynchronous group, 540 segments of coronary arteries were depicted, among which 515 segments could be evaluated (515/540, 95.37 ％ ). Conclusion Changing gantry ratation speed is able to avoid the harmonic of heart rate and gantry rotation caused by multi-sector reconstruction algorithm, therefore is helpful to improving imaging quality of MSCTCA.
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