Clinical NeuroscienceA reliability assessment of constrained spherical deconvolution-based diffusion-weighted magnetic resonance imaging in individuals with chronic stroke

- Assessed reliability of constrained spherical deconvolution (CSD) in chronic stroke.
- Reliability was generally good to excellent in the selected white matter tracts.
- CSD is a reliable white matter imaging technique in persons with chronic stroke.

BackgroundDiffusion-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.New methodEstablishing 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).ResultsICCs 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.Comparison with existing methodLike 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.ConclusionFuture work should address the reproducibility and utility of CSD-based metrics of tract number and tract volume.