降低人工髋关节CT扫描金属伪影的探析

目的:探讨IMAR(Iterative Metal Artifact Reduction, IMAR)算法对降低人工髋关节病人术区金属伪影的作用.方法:26例髋关节植入患者纳入本次研究,采用西门子双源CT(Siemens, SOMATOM Perspective)进行成像,CT重建的管电压分别采用80kVp和130kVp.分别在人工髋关节周围的肌肉和骨骼内选取4个感兴趣区(ROI),在每个ROI内测定出相应的平均CT值,并在同一扫描层面上远离人工髋关节的肌肉和骨骼内分别选取4个ROI作为对照,在两种管电压情况下比较IMAR和常规FBP(filtered back projections, FBP)两种算法的CT值.结果:IMAR算法与FBP算法对周围及远端肌肉和骨骼的CT值在两种管电压下均有明显差异,有统计学意义(P<0.01),IMAR均显示更低的CT值.结论:采用IMAR算法较传统的FBP算法相比能够明显降低人工髋关节植入后造成的金属伪影,并且采用IMAR算法结合高管电压较低管电压降低金属伪影效果更好.

Analysis of reducing artifacts in CT scanning of artificial hip joint

Objective: To investigate the effect of IMAR algorithm on reducing artifacts in the area of artificial hip joint.Methods: 26 cases of hip joint were included in this study, using SIEMENS dual source CT (Siemens, SOMATOM Perspective) imaging, CT reconstruction of the tube voltage were 80kVp and 130kVp.Selected 4 regions of interest in and around the bones of artificial hip joint muscle (ROI), set in each ROI measured the corresponding average CT value, and away from the hip at the same level of muscle and bone scan within 4 ROI were selected as control group, compared with IMAR in two kinds of tube voltage the case and the conventional FBP (filtered back projections, FBP) of the two algorithms CT.Results: IMAR algorithm and FBP algorithm had significant differences in the CT values of the peripheral and distal muscles and bones in two kinds of tube voltage, there was statistical significance (P<0.01), IMAR showed lower CT value.Conclusion:Compared with the traditional FBP algorithm, the IMAR algorithm can significantly reduce the artifacts caused by the implantation of artificial hip joint, and use the IMAR algorithm combined with the lower voltage of the executive voltage to reduce the effect of metal artifacts.