Three-tissue compositional analysis reveals in-vivo microstructural heterogeneity of white matter hyperintensities following stroke

Wasim Khan; Natalia Egorova; Mohamed Salah Khlif; Remika Mito; Thijs Dhollander; Amy Brodtmann

doi:10.1016/j.neuroimage.2020.116869

Three-tissue compositional analysis reveals in-vivo microstructural heterogeneity of white matter hyperintensities following stroke

Neuroimage. 2020 Sep:218:116869. doi: 10.1016/j.neuroimage.2020.116869. Epub 2020 Apr 22.

Authors

Wasim Khan¹, Natalia Egorova², Mohamed Salah Khlif³, Remika Mito³, Thijs Dhollander⁴, Amy Brodtmann⁵

Affiliations

¹ Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia; Department of Neuroimaging, Institute of Psychiatry, Psychology, and Neuroscience (IoPPN), King's College London, UK. Electronic address: will.khan@monash.edu.
² Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia; Melbourne School of Psychological Sciences, University of Melbourne, Victoria, Australia.
³ Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
⁴ Developmental Imaging, Murdoch Children's Research Institute, Melbourne, Australia.
⁵ Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia; Melbourne Dementia Research Centre, University of Melbourne, Victoria, Australia.

PMID: 32334092
DOI: 10.1016/j.neuroimage.2020.116869

Abstract

White matter hyperintensities (WMHs) are frequently observed on brain scans of older individuals and are associated with cognitive impairment and vascular brain burden. Recent studies have shown that WMHs may only represent an extreme end of a diffuse pathological spectrum of white matter (WM) degeneration. The present study investigated the microstructural characteristics of WMHs using an advanced diffusion MRI modelling approach known as Single-Shell 3-Tissue Constrained Spherical Deconvolution (SS3T-CSD), which provides information on different tissue compartments within each voxel. The SS3T-CSD method may provide complementary information in the interpretation of pathological tissue through the tissue-specific microstructural compositions of WMHs. Data were obtained from stroke patients enrolled in the Cognition and Neocortical Volume After Stroke (CANVAS) study, a study examining brain volume and cognition after stroke. WMHs were segmented using an automated method, based on fluid attenuated inversion recovery (FLAIR) images. Automated tissue segmentation was used to identify normal-appearing white matter (NAWM). WMHs were classified into juxtaventricular, periventricular and deep lesions, based on their distance from the ventricles (3-10 mm). We aimed to compare in stroke participants the microstructural composition of the different lesion classes of WMHs and compositions of NAWM to assess the in-vivo heterogeneity of these lesions. Results showed that the 3-tissue composition significantly differed between WMHs classes and NAWM. Specifically, the 3-tissue compositions for juxtaventricular and periventricular WMHs both exhibited a relatively greater fluid-like (free water) content, which is compatible with a presence of interstitial fluid accumulation, when compared to deep WMHs. These findings provide evidence of microstructural heterogeneity of WMHs in-vivo and may support new insights for understanding the role of WMH development in vascular neurodegeneration.

Keywords: 3-Tissue; Compositional analysis; Diffusion MRI; Stroke; White matter hyperintensities.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aged
Brain / diagnostic imaging*
Brain / pathology
Diffusion Magnetic Resonance Imaging / methods
Female
Humans
Image Interpretation, Computer-Assisted / methods*
Male
Middle Aged
Neuroimaging / methods*
Stroke / diagnostic imaging*
Stroke / pathology
White Matter / diagnostic imaging*
White Matter / pathology