Research Assistant Professor, Departments of Radiology & Clinical Neurosciences, University of Calgary, Canada

Speech Title: Imaging assessment of remyelination using novel meaures of tissue directionality
Abstract: Precise measurement of remyelination has been an ogoing challenge. The goal here was to evaluate myelin changes using a new method named structure tensor analysis in histology and magnetic resonance imaging (MRI) using a model of multiple sclerosis (MS). Demyelination was induced in the dorsal column of mouse spinal cord. Nine mice underwent 9.4T MRI at days 0 (healthy myelin), 7 (demyelination), and 14 & 28 days (remyelination). Corresponding histological images were stained with luxol fast blue for myelin. Structure tensor analysis was applied to MRI and histology to quantify the alignment of both lesions and the control tissue. Demyelinated lesions had significantly lower coherency and energy but higher angular entropy than intact myelin. During remyelination, all of these metrics show significant improvement, particularly the energy, which is a measure of total alignment directions in an area. This pattern of change is consistent between MRI and histology. These findings suggest that remyelination is associated with reduced complexity of tissue alignment and can be detected using MRI. Structure tensor analysis may serve as a new quantitative tool for assessing white matter repair, which is critical for monitoring disease development and treatments in MS and similar disorders.
Keywords: structure tensor analysis, MRI, MS, remyelination, tissue alignment