title: Whole brain white matter changes revealed by multiple diffusion metrics in multiple sclerosis: a TBSS study.
abstract: OBJECTIVE
  To investigate whole brain white matter changes in multiple sclerosis (MS) by multiple diffusion indices, we examined patients with diffusion tensor imaging and utilized tract-based spatial statistics (TBSS) method to analyze the data.
  
  
  METHODS
  Forty-one relapsing-remitting multiple sclerosis (RRMS) patients and 41 age- and gender-matched normal controls were included in this study. Diffusion weighted images were acquired by employing a single-shot echo planar imaging sequence on a 1.5 T MR scanner. Voxel-wise analyses of multiple diffusion metrics, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) were performed with TBSS.
  
  
  RESULTS
  The MS patients had significantly decreased FA (9.11%), increased MD (8.26%), AD (3.48%) and RD (13.17%) in their white matter skeletons compared with the controls. Through TBSS analyses, we found abnormal diffusion changes in widespread white matter regions in MS patients. Specifically, decreased FA, increased MD and increased RD were involved in whole-brain white matter, while several regions exhibited increased AD. Furthermore, white matter regions with significant correlations between the diffusion metrics and the clinical variables (the EDSS scores, disease durations and white matter lesion loads) in MS patients were identified.
  
  
  CONCLUSIONS
  Widespread white matter abnormalities were observed in MS patients revealed by multiple diffusion metrics. The diffusion changes and correlations with clinical variables were mainly attributed to increased RD, implying the predominant role of RD in reflecting the subtle pathological changes in MS.
authors.affiliation: Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China. asiaeurope80@gmail.com
authors.forename: Yaou
authors.initials: Y
authors.lastname: Liu
authors.forename: Yunyun
authors.initials: Y
authors.lastname: Duan
authors.forename: Yong
authors.initials: Y
authors.lastname: He
authors.forename: Chunshui
authors.initials: C
authors.lastname: Yu
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Huang
authors.forename: Jing
authors.initials: J
authors.lastname: Ye
authors.forename: Paul M
authors.initials: PM
authors.lastname: Parizel
authors.forename: Kuncheng
authors.initials: K
authors.lastname: Li
authors.forename: Ni
authors.initials: N
authors.lastname: Shu
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000473:pathology*; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult