Development of Novel Magnetic Resonance Imaging Techniques to Evaluate Plasticity in the Injured Human Cervical Spinal Cord

Traumatic injury to the human spinal cord is a devastating condition that results in motor and sensory impairment. The goal of this thesis is to develop magnetic resonance imaging techniques as a biomarker to evaluate the human spinal cord after injury. The specific aims are: 1a) to characterize the standard T1 and T2-weighted intramedullary spinal cord signal characteristics first used by clinicians treating spinal cord injury in order to classify patients along a spectrum of injury severity; 1b) to calculate the sensitivity and specificity of MRI biomarkers to determine neurological function and 1c) to determine whether standard T1 and T2-weighted imaging biomarkers offer an advantage over clinical examination to predict neurological outcomes. 2) To determine whether spinal functional MRI can be used to distinguish spinal cord injury patients from healthy controls by 2a) determining whether there is an abnormal neuro-vascular response to afferent stimulation in dermatomes of normal sensation, above the level of injury, in spinal cord injury (SCI) patients 2b) to determine whether the neuro-vascular response to afferent stimulation in dermatomes of altered sensory perception, below the level of injury, is correlated to the degree of sensory loss and 2c) to determine the functional connectivity between regions of the spinal cord that process an afferent stimulus and other regions of the brainstem-spinal cord axis. 3) To outline the diversity of segmental anatomy of the human spinal cord across a cohort of individuals by 3a) measuring the position of vertebral bodies and spinal cord segments relative to the ponto-medullary junction; 3b) to calculate the relative positions of vertebral bodies and spinal cord segments; and 3c) to predict the position of spinal cord segments. Results indicate that 1) standard T1 and T2-weighted intramedullary spinal cord signal characteristics offer no advantage over clinical examination to predict prognosis. 2) Spinal fMRI can be utilized to provide evidence of spinal cord plasticity after traumatic injury and 3) there is natural diversity of the position of vertebral and spinal cord segments relative to the ponto-medullary junction that should be taken into account for advanced imaging studies. Collectively, the new knowledge presented herein contributes to the advancement of imaging techniques to investigate the human spinal cord.