Date of Award

Spring 2008

Document Type

Dissertation - Restricted

Degree Name

Doctor of Philosophy (PhD)


Biomedical Engineering

First Advisor

Schmit, Brian D.

Second Advisor

Ropella, Kristina M.

Third Advisor

Kurpad, Shekar N.


Diffusion tensor magnetic resonance imaging (DTMRI or DTI) is a magnetic resonance imaging (MRI) technique that quantifies the diffusion of hydrogen atoms, primarily in unbound water molecules. In the central nervous system (CNS) diffusion is anisotropic, having a preferred direction of free diffusion parallel with axon orientation. Diffusion perpendicular to axons is restricted due to boundaries from the axon cell membrane, myelin sheath, as well as internal structures including neurofilaments and microtubules. Thus, by monitoring the changes in diffusion characteristics within the CNS in vivo, or more specifically the spinal cord, we may deduce the microstructural organization along with predict white matter integrity following traumatic injury. The primary purpose of this study was to characterize the spatiotemporal changes in diffusion characteristics following spinal cord injury (SCI) using DTI. In order to accomplish this objective a rat model of spinal cord injury was used and the rat spinal cord was imaged using high-field in vivo and ex vivo DTI at various time points and spatial locations during the progression of injury. Previous studies aimed at characterizing DTI in SCI have focused only up to 6 mm rostral and caudal from the lesion, and only up to 12 weeks post-injury. Based on our preliminary experience with human acute and chronic SCI, we hypothesized significant changes in DTI characteristics remote and near to the lesion exist, and these changes continue to evolve much longer than 12 weeks after injury...



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