Whole cord diffusion imaging of post-mortem human spinal cord injury reveals extent and potential timeline of axonal swelling and degeneration

Motivation: Following spinal cord injury (SCI) changes in tissue microstructure occur throughout the length of the cord which are not detectable with conventional MRI. Goal(s): To characterize whole cord diffusion MRI metrics in human SCI post-mortem tissue, including the effect of injury-to-death interval on diffusion MRI metrics. Approach: Two full-length spinal cords were imaged at 7T. DTI and ActiveAx metrics were extracted from white matter tracts. Results: Changes in fractional anisotropy, axon density, and axon diameter were observed downstream of the injury epicentre in the case with a longer injury-to-death interval. Transience in diffusion metrics may indicate the extent of axonal degeneration and swelling. Impact: Diffusion MRI may be a useful tool in understanding the extent and progression of spinal cord injury. Insight into axonal swelling and degeneration following spinal cord injury could aid clinicians in predicting patient prognosis.