title: Application of diffusion tensor imaging in multiple system atrophy: the involvement of pontine transverse and longitudinal fibers.
abstract: OBJECTIVE
  Many studies have demonstrated the degeneration of pontine transverse and longitudinal tracts in multiple system atrophy (MSA). One purpose of this study was to assess whether diffusion tensor imaging (DTI) can show microstructural abnormalities in these tracts in patients with MSA cerebellar type (MSA-C). Another purpose was to determine the correlation between cross sign progress and pontine fiber degeneration in these patients.
  
  
  METHODS
  Thirty patients with MSA-C and 30 healthy volunteers underwent conventional magnetic resonance imaging (MRI) and DTI. Regions of interest were placed in both cerebral peduncles, the posterior limbs of the internal capsule and the pontine crossing tract of each subject. Quantitative indexes such as fractional anisotropy (FA) and mean diffusivity (MD) were compared between groups by analysis of variance. Cross sign was divided into three grades as follows: 0, no cross sign; 1, vertical line only; 2, clear cross sign. Spearman rank correlation analysis was used between FA, MD, and the cross grade in patients with MSA-C.
  
  
  RESULTS
  FA and MD in the MSA-C group, and each cross grade, showed statistically significant differences compared to control groups. There was a close correlation between all measures. FA decreased and MD increased, and cross grade formed gradually in the patients.
  
  
  CONCLUSIONS
  DTI can identify microstructural abnormalities in pontine transverse and longitudinal fibers even in patients without abnormalities on conventional MRI. Along with pontine transverse tract degeneration, the cross sign develops accompanied by the start of longitudinal tract degeneration, ultimately resulting in the complete formation of a cross sign.
authors.affiliation: Department of Radiology, Xiangya Hospital, Central South University , Changsha, Hunan , China.
authors.forename: Haixia
authors.initials: H
authors.lastname: Yang
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Wang
authors.forename: Weihua
authors.initials: W
authors.lastname: Liao
authors.forename: Gaofeng
authors.initials: G
authors.lastname: Zhou
authors.forename: Lang
authors.initials: L
authors.lastname: Li
authors.forename: Lirong
authors.initials: L
authors.lastname: Ouyang
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016880:Anisotropy; D002531:Cerebellum / Q000473:pathology; D065850:Cerebral Peduncle / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D020772:Internal Capsule / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000473:pathology*; D011149:Pons / Q000473:pathology*; D013223:Statistics as Topic
keywords: diffusion tensor imaging (DTI); fractional anisotropy (FA); magnetic resonance imaging (MRI); mean diffusivity (MD); multiple system atrophy (MSA)