title: Macro- and microstructural changes in patients with spinocerebellar ataxia type 6: assessment of phylogenetic subdivisions of the cerebellum and the brain stem.
abstract: OBJECTIVE
  Site-specific degeneration patterns of the infratentorial brain in relation to phylogenetic origins may relate to symptoms in patients with spinocerebellar degeneration, but the patterns are still unclear. We investigated macro- and microstructural changes of the infratentorial brain based on phylogenetic origins and their correlation with symptoms in patients with spinocerebellar ataxia type 6.
  
  
  METHODS
  MR images of 9 patients with spinocerebellar ataxia type 6 and 9 age- and sex-matched controls were obtained. We divided the infratentorial brain on the basis of phylogenetic origins and performed an atlas-based analysis. Comparisons of the 2 groups and a correlation analysis assessed with the International Cooperative Ataxia Rating Scale excluding age effects were performed.
  
  
  RESULTS
  A significant decrease of fractional volume and an increase of mean diffusivity were seen in all subdivisions of the cerebellum and in all the cerebellar peduncles except mean diffusivity in the inferior cerebellar peduncle in patients compared with controls (P < .0001 to <.05). The bilateral anterior lobes showed the strongest atrophy. Fractional volume decreased mainly in old regions, whereas mean diffusivity increased mainly in new regions of the cerebellum. Reflecting this tendency, the International Cooperative Ataxia Rating Scale total score showed strong correlations in fractional volume in the right flocculonodular lobe and the bilateral deep structures and in mean diffusivity in the bilateral posterior lobes (r = 0.73 to ±0.87).
  
  
  CONCLUSIONS
  We found characteristic macro- and microstructural changes, depending on phylogenetic regions of the infratentorial brain, that strongly correlated with clinical symptoms in patients with spinocerebellar ataxia type 6.
authors.affiliation: From the Russell H. Morgan Department of Radiology and Radiological Science (K.S., K.I., K.O., S.M.) Department of Radiology (K.S.), Juntendo University School of Medicine, Tokyo, Japan satokana.tky@gmail.com.
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.affiliation: From the Russell H. Morgan Department of Radiology and Radiological Science (K.S., K.I., K.O., S.M.) Department of Radiology (K.I.), University of Yamanashi, Yamanashi, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ishigame
authors.affiliation: Departments of Radiology (S.H.Y.) Neurology (S.H.Y.) Ophthalmology (S.H.Y.).
authors.forename: S H
authors.initials: SH
authors.lastname: Ying
authors.affiliation: From the Russell H. Morgan Department of Radiology and Radiological Science (K.S., K.I., K.O., S.M.).
authors.forename: K
authors.initials: K
authors.lastname: Oishi
authors.affiliation: Center for Imaging Science (M.I.M.), Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: M I
authors.initials: MI
authors.lastname: Miller
authors.affiliation: From the Russell H. Morgan Department of Radiology and Radiological Science (K.S., K.I., K.O., S.M.) F.M. Kirby Research Center for Functional Brain Imaging (S.M.), Kennedy Krieger Institute, Baltimore, Maryland.
authors.forename: S
authors.initials: S
authors.lastname: Mori
mesh_terms: D000328:Adult; D000368:Aged; D001284:Atrophy / Q000473:pathology; D001933:Brain Stem / Q000473:pathology*; D002531:Cerebellum / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D012720:Severity of Illness Index; D020754:Spinocerebellar Ataxias / Q000473:pathology*