Objective Spinal fMRI Metrics Distinguish Complete and Incomplete Clinical Grade in Chronic Spinal Cord Injury

David Cadotte, MD1, Patrick Stroman, PhD1, David Mikulis, MD, PhD1, Rachael Bosma1, Michael Fehlings, MD, PhD1

1Toronto, Canada

Keywords: cervical spine, trauma, magnetic resonance imaging, spinal cord, spinal cord injury

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Abstract

      
     In an effort to define quantitative spinal fMRI metrics that can be used to distinguish between ASIA complete and incomplete injury, we compare a cohort of healthy controls to those with chronic SCI (<1 year) who are either complete (ASIA A) or incomplete (ASIA B, C, or D).
     32 people were examined: 20 control, 3 ASIA A complete SCI and 9 incomplete SCI.
     Using an automated thermal delivery system, heat (44°C) was applied to 2 dermatomes above and 2 below the level of SCI. Spinal fMRI data was collected on a 3T system using a SEEP-based protocol developed by our group (SSFSE, TE=30msec, TR=1sec). Data were spatially normalized and analyzed using the general linear model (P=0.001). We divided the cervical spinal cord into zones based on known anatomical relationships of nerve rootlets entering the cord from the segmental nerve root. We calculated the number of active voxels in the stimulated zones of the spinal cord.
      The average number of active voxels in the dorsal quadrant of the spinal cord zone (corresponding to the dermatome stimulated) was calculated. The average number of active voxels are: Chronic SCI patients: 325 (complete injury); 619 (incomplete injury) and 760 in healthy controls.
     This is a retrospective study.
     This work represents the first attempt to define objective metrics that distinguish between clinical grades of injury.
     The number of active voxels in the dorsal quadrant of the spinal cord zone (corresponding to the dermatome stimulated) shows a robust ability to distinguish between ASIA complete, incomplete injury and healthy controls.


Acknowledgements

Project Roles:

D. Cadotte (), P. Stroman (), D. Mikulis (), R. Bosma (), M. Fehlings ()