MRI correlates of white matter structure in intact myelin vs. myelin debris –ex vivo study in injured rat spinal cord

Introduction A wide array of processes occurs after spinal cord injury, including white matter demyelination and proximal and distal Wallerian degeneration. The demyelination and interruption of the axonal tract ultimately leads to the functional loss seen in spinal cord injuries. Therefore it is important to have a non-invasive technique that is able to track myelin in spinal cords. There are several MR techniques aimed at this, including quantitative T2, diffusion tensor imaging (DTI), and quantitative magnetization transfer. Because myelin cannot be imaged directly with MR, these techniques focus on indirect measurement of myelin through probing the properties of the surrounding water. While quantitative T2 and DTI are able to generate indirect measures of myelin and axonal density, there is currently no technique capable of distinguishing between intact/functioning myelin and myelin debris. This study focuses on comparing several MR parameters between intact myelin and myelin debris in a rat spinal cord injury model.