Diffusion Tensor Imaging of Motor Connectivity in Selected Subjects with Stroke

Type of content
Theses / Dissertations
Publisher's DOI/URI
Thesis discipline
Physics
Degree name
Master of Science
Publisher
University of Canterbury. Physics and Astronomy
Journal Title
Journal ISSN
Volume Title
Language
Date
2007
Authors
Smale, Peter Rich
Abstract

Diffusion Tensor Magnetic Resonance Imaging (DTI) is a recently-developed technique that can image in vivo the white matter pathways of the central nervous system. This study used 12-direction diffusion-weighted MRI data from nine stroke patients acquired as part of a three-year stroke rehabilitation study coordinated by the Movement Neuroscience Laboratory at the University of Auckland. DTI was used to investigate corticospinal connectivity. From the FA maps, it is found that in those patients whose motor connectivity has been compromised by the stroke to the extent that no motor evoked potential (MEP) can be elicited from a selected affected muscle group, the asymmetry in mean FA values in the posterior limbs of the internal capsules (PLICs) is correlated with functional recovery as measured by the Fugl-Meyer clinical score. Using probabilistic tractography in the contralesional hemisphere produced CST location and somatotopy results that were consistent with those of previous studies. However, in the ipsilesional hemisphere, connectivity results were highly variable. A measure of change in symmetry of mean connectivity is found to correlate with functional recovery as measured by change in FM score. This supports previous work which has correlated CST integrity and functional improvement and it supports the theory that functional recovery after stroke depends on the extent to which motor CNS symmetry can be regained in the new post-stroke architecture. It also suggests that the movement of the fMRI activations occurs in such a way as to make the most of the preserved white matter connectivity.

Description
Citation
Keywords
DTI, diffusion tensor imaging, MRI, magnetic resonance imaging, stroke, tractography
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Rights
Copyright Peter Rich Smale