title: Altered topological organization of white matter structural networks in patients with neuromyelitis optica.
abstract: OBJECTIVE
  To investigate the topological alterations of the whole-brain white-matter (WM) structural networks in patients with neuromyelitis optica (NMO).
  
  
  METHODS
  The present study involved 26 NMO patients and 26 age- and sex-matched healthy controls. WM structural connectivity in each participant was imaged with diffusion-weighted MRI and represented in terms of a connectivity matrix using deterministic tractography method. Graph theory-based analyses were then performed for the characterization of brain network properties. A multiple linear regression analysis was performed on each network metric between the NMO and control groups.
  
  
  RESULTS
  The NMO patients exhibited abnormal small-world network properties, as indicated by increased normalized characteristic path length, increased normalized clustering and increased small-worldness. Furthermore, largely similar hub distributions of the WM structural networks were observed between NMO patients and healthy controls. However, regional efficiency in several brain areas of NMO patients was significantly reduced, which were mainly distributed in the default-mode, sensorimotor and visual systems. Furthermore, we have observed increased regional efficiency in a few brain regions such as the orbital parts of the superior and middle frontal and fusiform gyri.
  
  
  CONCLUSIONS
  Although the NMO patients in this study had no discernible white matter T2 lesions in the brain, we hypothesize that the disrupted topological organization of WM networks provides additional evidence for subtle, widespread cerebral WM pathology in NMO.
authors.affiliation: Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, PR China.
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: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Mingrui
authors.initials: M
authors.lastname: Xia
authors.forename: Chunshui
authors.initials: C
authors.lastname: Yu
authors.forename: Huiqing
authors.initials: H
authors.lastname: Dong
authors.forename: Jing
authors.initials: J
authors.lastname: Ye
authors.forename: Helmut
authors.initials: H
authors.lastname: Butzkueven
authors.forename: Kuncheng
authors.initials: K
authors.lastname: Li
authors.forename: Ni
authors.initials: N
authors.lastname: Shu
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology*; D009471:Neuromyelitis Optica / Q000473:pathology*