Relationship of Cortical MRI to ASIA Impairment Scale in Chronic Spinal Cord Injury

Preliminary data suggests that spinal cord and sensorimotor cortical function is disrupted following SCI and individuals with SCI have a different pattern of brain activation compared to individuals without any injury. We will perform:

1. Diffusion tensor imaging (DTI) to perform fiber tracking
2. Both task-activated and resting state functional magnetic resonance imaging (fMRI) to study functional connectivity
3. Structural MRI to acquire conventional structural images such as T1-weighted (T1w) and T2-weighted (T2w) images to characterize the effect of SCI on the central nervous system

Our goal is to related neurological function after SCI to MRI assessment of the integrity of cortical white matter, organizational changes to the structure of the central nervous system, functional activity, and changes in activity of the brain, including:

1. Structural preservation of white matter tracts in motor and sensory cortical areas measured by metrics derived from DTI (fractional anisotropy (FA), mean diffusivity (MD), and eigenvalues) will be abnormal in SCI subjects, reflecting structural changes such as atrophy and Wallerian degeneration. Degree of abnormality will be higher in patients with complete (American Spinal Injury Association (ASIA) A) injury as compared to incomplete (ASIA B-D) injury.
2. Preservation of functional networks in motor and sensory cortical areas measured by fMRI-derived metrics (mean t values and blood oxygen level dependent contrast (BOLD) volume) will relate with ASIA scores. In particular, higher degree of depression of mean t value, motor and sensory BOLD volume will relate with a complete motor and sensory impairment (ASIA A) as compared to incomplete impairment (ASIA B-D).