title: Diffusion tensor imaging shows structural remodeling of stroke mirror region: results from a pilot study.
abstract: BACKGROUND
  The role of the non-injured hemisphere in stroke recovery is poorly understood. In this pilot study, we sought to explore the presence of structural changes detectable by diffusion tensor imaging (DTI) in the contralesional hemispheres of patients who recovered well from ischemic stroke.
  
  
  METHODS
  We analyzed serial DTI data from 16 stroke patients who had moderate initial neurological deficits (NIHSS scores 3-12) and good functional outcome at 3-6 months (NIHSS score 0 or modified Rankin Score ≤1). We segmented the brain tissue in gray and white matter (GM and WM) and measured the apparent diffusion coefficient (ADC) and fractional anisotropy in the infarct, in the contralesional infarct mirror region as well as in concentrically expanding regions around them.
  
  
  RESULTS
  We found that GM and WM ADC significantly increased in the infarct region (p < 0.01) from acute to chronic time points, whereas in the infarct mirror region, GM and WM ADC increased (p < 0.01) and WM fractional anisotropy decreased (p < 0.05). No significant changes were detected in other regions.
  
  
  CONCLUSIONS
  DTI-based metrics are sensitive to regional structural changes in the contralesional hemisphere during stroke recovery. Prospective studies in larger cohorts with varying levels of recovery are needed to confirm our findings.
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. cristina.granziera@chuv.ch
authors.forename: Cristina
authors.initials: C
authors.lastname: Granziera
authors.forename: Hakan
authors.initials: H
authors.lastname: Ay
authors.forename: Susan P
authors.initials: SP
authors.lastname: Koniak
authors.forename: Gunnar
authors.initials: G
authors.lastname: Krueger
authors.forename: A Gregory
authors.initials: AG
authors.lastname: Sorensen
mesh_terms: D000328:Adult; D000368:Aged; D016880:Anisotropy; D001931:Brain Mapping; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000209:etiology; D010865:Pilot Projects; D012189:Retrospective Studies; D020521:Stroke / Q000473:pathology* / Q000503:physiopathology*; D013997:Time Factors; D055815:Young Adult