title: MR Imaging in Spinocerebellar Ataxias: A Systematic Review.
abstract: Polyglutamine expansion spinocerebellar ataxias are autosomal dominant slowly progressive neurodegenerative diseases with no current treatment. MR imaging is the best-studied surrogate biomarker candidate for polyglutamine expansion spinocerebellar ataxias, though with conflicting results. We aimed to review quantitative central nervous system MR imaging technique findings in patients with polyglutamine expansion spinocerebellar ataxias and correlations with well-established clinical and molecular disease markers.
  
  
  
  We searched MEDLINE, LILACS, and Cochrane data bases of clinical trials between January 1995 and January 2016, for quantitative MR imaging volumetric approaches, MR spectroscopy, diffusion tensor imaging, or other quantitative techniques, comparing patients with polyglutamine expansion spinocerebellar ataxias (SCAs) with controls. Pertinent details for each study regarding participants, imaging methods, and results were extracted.
  
  
  
  After reviewing the 706 results, 18 studies were suitable for inclusion: 2 studies in SCA1, 1 in SCA2, 15 in SCA3, 1 in SCA7, 1 in SCA1 and SCA6 presymptomatic carriers, and none in SCA17 and dentatorubropallidoluysian atrophy. Cerebellar hemispheres and vermis, whole brain stem, midbrain, pons, medulla oblongata, cervical spine, striatum, and thalamus presented significant atrophy in SCA3. The caudate, putamen and whole brain stem presented similar sensitivity to change compared with ataxia scales after 2 years of follow-up in a single prospective study in SCA3. MR spectroscopy and DTI showed abnormalities only in cross-sectional studies in SCA3. Results from single studies in other polyglutamine expansion spinocerebellar ataxias should be replicated in different cohorts.
  
  
  
  Additional cross-sectional and prospective volumetric analysis, MR spectroscopy, and DTI studies are necessary in polyglutamine expansion spinocerebellar ataxias. The properties of preclinical disease biomarkers (presymptomatic) of MR imaging should be targeted in future studies.
authors.affiliation: From the Departments of Radiology (A.K., L.M.V.).
authors.forename: A
authors.identifier: 0000-0003-1345-3810
authors.initials: A
authors.lastname: Klaes
authors.affiliation: Medical Genetics Services (E.R., L.B.J., J.A.M.S.), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.
authors.forename: E
authors.identifier: 0000-0002-3065-3550
authors.initials: E
authors.lastname: Reckziegel
authors.affiliation: Departments of Neurology (M.C.F., T.J.R.R.).
authors.forename: M C
authors.identifier: 0000-0003-0898-2419
authors.initials: MC
authors.lastname: Franca
authors.affiliation: Departments of Neurology (M.C.F., T.J.R.R.) Cosmic Rays and Chronology (T.J.R.R.), Universidade Estadual de Campinas, Campinas, Brazil.
authors.forename: T J R
authors.identifier: 0000-0003-0765-4587
authors.initials: TJ
authors.lastname: Rezende
authors.affiliation: From the Departments of Radiology (A.K., L.M.V.) Department of Internal Medicine (L.M.V., L.B.J.).
authors.forename: L M
authors.identifier: 0000-0002-1653-5582
authors.initials: LM
authors.lastname: Vedolin
authors.affiliation: Medical Genetics Services (E.R., L.B.J., J.A.M.S.), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil Department of Internal Medicine (L.M.V., L.B.J.) Postgraduate Program in Medicine: Medical Sciences (L.B.J.), Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: L B
authors.identifier: 0000-0001-6907-5068
authors.initials: LB
authors.lastname: Jardim
authors.affiliation: Medical Genetics Services (E.R., L.B.J., J.A.M.S.), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil jsaute@hcpa.edu.br.
authors.forename: J A
authors.identifier: 0000-0003-1141-6573
authors.initials: JA
authors.lastname: Saute
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D059906:Neuroimaging / Q000379:methods*; D020754:Spinocerebellar Ataxias / Q000000981:diagnostic imaging* / Q000473:pathology*