基于场图的磁共振扩散张量成像变形矫正和信号补偿  

Field map-based rectification of susceptibility distortion and signal compensation in diffusion tensor imaging

作　　者：康泰山[1] 杨天和[1] 林建忠[1] 张家兴[2] KANG Tai-shan;YANG Tian-he;LIN Jian-zhong;ZHANG Jia-xing(Department of MRI, Zhongshan Affiliated Hospital of Xiamen University, Xiamen 361004, China;Institute of Brain Diseases and Cognition, Medical College of Xiamen University,Xiamen 361102, China)

机构地区：[1]厦门大学附属中山医院磁共振科,厦门361004 [2]厦门大学医学院脑疾病与认知研究所,厦门361102

出　　处：《磁共振成像》2017年第8期609-613,共5页Chinese Journal of Magnetic Resonance Imaging

基　　金：国家自然科学基金面上项目(编号:81471630)~~

摘　　要：目的采用基于体素的场图对磁共振弥散张量成像(diffusion-tensor imaging,DTI)进行几何变形矫正及信号补偿研究,扩大DTI临床研究及应用价值。材料与方法获取29名健康人脑场图,分别对其DTI进行相位反卷积计算及信号校准补偿,将结果配准到3D结构图像。选择对磁场敏感的双侧颅底额叶和颞叶作为观察脑区,对磁场不敏感的丘脑作为对照脑区,对部分各向异性(fractional anisotropy,FA)值及信号的差异及其与结构像的形态差异进行统计分析。结果在颅底额叶和颞叶,DTI的磁敏感变形得到了矫正,因场不均性导致的信号损失得到了补偿。结论高场中DTI的畸变及体素信号丢失可应用场图的校准得到明显矫正,有利于进一步扩大高场DTI在临床中的应用价值。Objective:This study was designed to employ the voxel-based fieldmap to rectify the geometric deformation and compensate the signal loss of diffusiontensor imaging(DTI),and thus facilitate the studies and clinical applications ofDTI.Materials and Methods:Brain field maps from29healthy persons were firstused to get B1field heterogeneous signals,and then the compensation and phasedisconsolation of signals were performed.Finally,the geometry deformations of DTIwere rectified and registered to3D images.Magnetic sensitive bilateral temporallobes and frontal lobes were selected as regions of interesting and meanwhile,magnetic insensitive thalamus was selected as control area.Results:Geometrydeformations of DTI produced by different susceptibilities between specific tissueswere completely rectified,and thus the signal loss was compensated and the accuracy ofDTI was significantly enhanced.Conclusion:Signal compensations and deformationrectifications can be well achieved using field map,which may improve theapplications of DTI in neurosurgery.

关 键 词：弥散张量成像 场图 变形矫正 信号补偿 

分 类 号：R445.2[医药卫生—影像医学与核医学] R338.2[医药卫生—诊断学]