title: Spinal cord atrophy in spinocerebellar ataxia type 3 and 6 : impact on clinical disability.
abstract: OBJECTIVE
  To quantify spinal cord atrophy and its impact on clinical disability in spinocerebellar ataxia (SCA) type 3 and 6.
  
  
  METHODS
  Atrophy of the upper spinal cord was assessed by high resolution T1-weighted MRI of patients with SCA3 (n = 14) and SCA6 (n = 10). Furthermore, two groups of age- and sex-matched healthy control subjects (n = 24,) corresponding to the two SCA groups, were studied. Images were post-processed by a semi-automated volumetry method combining a marker based segmentation and an automatic histogram method facilitating highly reliable quantification and morphometry of the upper cervical cord in vivo.
  
  
  RESULTS
  We found a significant reduction of normalized mean crosssectional area of the spinal cord in SCA3 (p < 0.0005), whereas in SCA6 patients normalized mean crosssectional area was in the normal range (p = 0.379). No correlation was found between spinal cord atrophy and disease duration as well as CAG repeat length in both subtypes. In SCA6 a negative dependency between clinical disability, as expressed by the International Cooperative Ataxia Rating Scale as a well established ataxia score, and the mean cross-sectional area was found (p = 0.02). A similar correlation was observed in SCA3 but did not reach statistical significance.
  
  
  CONCLUSIONS
  Our results quantify for the first time in vivo spinal cord atrophy as a non-cerebellar neurodegenerative process in SCA3. Our results suggest MR volumetry of the upper cervical cord as a marker of functional importance in SCA3 and SCA6.
authors.affiliation: Dept. of Diagnostic and Interventional Radiology and Nuclear Medicine, St. Josef Hospital Ruhr University Bochum, Gudrunstr. 56, 44791, Bochum, Germany. Carsten.Lukas@ruhr-uni-bochum.de
authors.forename: Carsten
authors.initials: C
authors.lastname: Lukas
authors.forename: Horst K
authors.initials: HK
authors.lastname: Hahn
authors.forename: Barbara
authors.initials: B
authors.lastname: Bellenberg
authors.forename: Kerstin
authors.initials: K
authors.lastname: Hellwig
authors.forename: Christoph
authors.initials: C
authors.lastname: Globas
authors.forename: Sebastian K
authors.initials: SK
authors.lastname: Schimrigk
authors.forename: Odo
authors.initials: O
authors.lastname: Köster
authors.forename: Ludger
authors.initials: L
authors.lastname: Schöls
mesh_terms: D000328:Adult; D000368:Aged; D001284:Atrophy / Q000209:etiology; D016022:Case-Control Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D017827:Machado-Joseph Disease / Q000150:complications*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013116:Spinal Cord / Q000473:pathology*; D020754:Spinocerebellar Ataxias / Q000150:complications*; D018709:Statistics, Nonparametric