title: A reliability assessment of constrained spherical deconvolution-based diffusion-weighted magnetic resonance imaging in individuals with chronic stroke.
abstract: BACKGROUND
  Diffusion-weighted magnetic resonance imaging (DW-MRI) is commonly used to assess white matter properties after stroke. Novel work is utilizing constrained spherical deconvolution (CSD) to estimate complex intra-voxel fiber architecture unaccounted for with tensor-based fiber tractography. However, the reliability of CSD-based tractography has not been established in people with chronic stroke.
  
  
  METHODS
  Establishing the reliability of CSD-based DW-MRI in chronic stroke. High-resolution DW-MRI was performed in ten adults with chronic stroke during two separate sessions. Deterministic region of interest-based fiber tractography using CSD was performed by two raters. Mean fractional anisotropy (FA), apparent diffusion coefficient (ADC), tract number, and tract volume were extracted from reconstructed fiber pathways in the corticospinal tract (CST) and superior longitudinal fasciculus (SLF). Callosal fiber pathways connecting the primary motor cortices were also evaluated. Inter-rater and test-retest reliability were determined by intra-class correlation coefficients (ICCs).
  
  
  RESULTS
  ICCs revealed excellent reliability for FA and ADC in ipsilesional (0.86-1.00; p<0.05) and contralesional hemispheres (0.94-1.00; p<0.0001), for CST and SLF fibers; and excellent reliability for all metrics in callosal fibers (0.85-1.00; p<0.05). ICC ranged from poor to excellent for tract number and tract volume in ipsilesional (-0.11 to 0.92; p≤0.57) and contralesional hemispheres (-0.27 to 0.93; p≤0.64), for CST and SLF fibers.
  
  
  CONCLUSIONS
  Like other select DW-MRI approaches, CSD-based tractography is a reliable approach to evaluate FA and ADC in major white matter pathways, in chronic stroke.
  
  
  CONCLUSIONS
  Future work should address the reproducibility and utility of CSD-based metrics of tract number and tract volume.
authors.affiliation: Graduate Program in Rehabilitation Sciences, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Snow
authors.affiliation: Graduate Program in Rehabilitation Sciences, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
authors.forename: Sue
authors.initials: S
authors.lastname: Peters
authors.affiliation: Division of Physical Therapy, School of Medicine, Emory University, Atlanta, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Borich
authors.affiliation: Biomedical Engineering Graduate Program, Faculty of Applied Science, University of British Columbia, Vancouver, Canada.
authors.forename: Navid
authors.initials: N
authors.lastname: Shirzad
authors.affiliation: Graduate Program in Rehabilitation Sciences, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Auriat
authors.affiliation: Graduate Program in Rehabilitation Sciences, Faculty of Medicine, University of British Columbia, Vancouver, Canada; The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia.
authors.forename: Kathryn S
authors.initials: KS
authors.lastname: Hayward
authors.affiliation: Graduate Program in Rehabilitation Sciences, Faculty of Medicine, University of British Columbia, Vancouver, Canada; Graduate Program in Neuroscience, Faculty of Medicine, University of British Columbia, Vancouver, Canada. Electronic address: lara.boyd@ubc.ca.
authors.forename: Lara A
authors.initials: LA
authors.lastname: Boyd
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016880:Anisotropy; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000473:pathology; D002908:Chronic Disease; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology; D009929:Organ Size; D015203:Reproducibility of Results; D020521:Stroke / Q000473:pathology*
keywords: Constrained spherical deconvolution; Diffusion-weighted magnetic resonance imaging; Intra-class correlation coefficient; Reliability; Stroke