Characterization of a novel, magnetic resonance imaging-compatible rodent model spinal cord injury device.

Abstract

Rodent models of acute spinal cord injury (SCI) are often used to investigate the effects of injury mechanism, injury speed, and cord displacement magnitude, on the ensuing cascade of biological damage in the cord. However, due to its small size, experimental observations have largely been limited to the gross response of the cord. To properly understand the relationship between mechanical stimulus and biological damage, more information is needed about how the constituent tissues of the cord (i.e., gray and white matter) respond to injurious stimuli. To address this limitation, we developed a novel magnetic resonance imaging (MRI)-compatible test apparatus that can impose either a contusion-type or dislocation-type acute cervical SCI in a rodent model and facilitate MR-imaging of the cervical spinal cord in a 7 T MR scanner. In this study, we present the experimental performance parameters of the MR rig. Utilizing cadaveric specimens and static radiographs, we report contusion magnitude accuracy that for a desired 1.8 mm injury, a nominal 1.78 mm injury (SD = 0.12 mm) was achieved. High-speed video analysis was employed to determine the injury speeds for both mechanisms and were found to be 1147 mm/s (SD = 240 mm/s) and 184 mm/s (SD = 101 mm/s) for contusion and dislocation injuries, respectively. Furthermore, we present qualitative pilot data from a cadaveric trial, employing the MR rig, to show the expected results from future studies.