title: Local tissue anisotropy decreases in cerebellopetal fibers and pyramidal tract in multiple system atrophy.
abstract: BACKGROUND
  One of the cardinal features in multiple system atrophy (MSA) is the white matter pathology: loss of myelin, astrocytosis, and glial cytoplasmic inclusions. The pathological changes of tissue microstructure can modify the diffusion behavior of water molecules, which can be assessed by diffusion tensor imaging (DTI).
  
  
  OBJECTIVE
  To explore the hypothesis of white matter degeneration in MSA.
  
  
  METHODS
  We studied 11 patients with clinically probable MSA and 10 age-matched controls. DTI was performed in both groups to measure fractional anisotropy (FA) in various regions of interest: the inferior cerebellar peduncle (ICP), middle cerebellar peduncle (MCP), superior cerebellar peduncle (SCP), basis pontis, internal capsule, and corpus callosum.
  
  
  RESULTS
  FA values in SCP and corpus callosum showed no significant difference between the MSA group and controls. By contrast, FA values decreased in the MSA group in the MCP, basis pontis and internal capsule. In addition, FA values in the MCP were negatively correlated with ataxia severity in the MSA group.
  
  
  CONCLUSIONS
  The areas showing decreased tissue anisotropy in DTI corresponded well with pathologically vulnerable areas in MSA. In addition, the local tissue anisotropy of MCP decreased in accordance with functional disability. These observations implied that DTI is a feasible method for in vivo evaluation of the white matter pathology in MSA.
authors.affiliation: Department of Neurology and Geriatrics, Department of Radiology, Kyoto Prefectural University of Medicine, Kaijicho 465 Kamigyo-ku, Kyoto, 601-0841, Japan. kenshiga@koto.kpu-m.ac.jp
authors.forename: Kensuke
authors.initials: K
authors.lastname: Shiga
authors.forename: Kei
authors.initials: K
authors.lastname: Yamada
authors.forename: Kenji
authors.initials: K
authors.lastname: Yoshikawa
authors.forename: Toshiki
authors.initials: T
authors.lastname: Mizuno
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Nishimura
authors.forename: Masanori
authors.initials: M
authors.lastname: Nakagawa
mesh_terms: D000368:Aged; D016880:Anisotropy; D002531:Cerebellum / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000473:pathology*; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D011712:Pyramidal Tracts / Q000473:pathology*