Detection of the neuronal activity occurring caudal to the site of spinal cord injury that is elicited during lower limb movement tasks

Study design: Functional magnetic resonance imaging ( fMRI) of the spinal cord ( spinal fMRI) was used to detect neuronal activity elicited by passive and active lower limb movement tasks, in regions caudal to the injury site in volunteers with spinal cord injury. Objectives: The objectives of this project are: ( 1) to assess the use of spinal fMRI as a tool for detecting neuronal function in the spinal cord below an injury, and ( 2) to characterize the neuronal response to active and passive movement tasks. Setting: Institute for Biodiagnostics, National Research Council of Canada, Winnipeg, Manitoba, Canada. Methods: fMRI of the spinal cord was carried out in 12 volunteers with cervical or thoracic spinal cord injuries. Spinal fMRI was carried out in a 1.5 T clinical MR system using established methods. Active and passive lower limb movement tasks were performed, and sagittal images spanning the entire lumbar spinal cord were obtained. Results: Activity was detected in all volunteers regardless of the extent of injury. During both active and passive participation, activity was seen caudal to the injury site, although the number of active voxels detected with passive movement was less than with the active movement task. Average percent signal change was 13.6% during active participation and 15.0% during passive participation. Conclusions: Spinal fMRI is able to detect a neuronal response during both active and passive lower limb movement tasks in the spinal cord caudal to the injury site. Sponsorship: This work was funded by a grant from the International Spinal Research Trust ( UK) and the Canada Research Chairs Program.