Tracking sensory system atrophy and outcome prediction in spinal cord injury.
OBJECTIVE
In patients with subacute spinal cord injury (SCI), the motor system undergoes progressive structural changes rostral to the lesion, which are associated with motor outcome. The extent to which the sensory system is affected and how this relates to sensory outcome are uncertain.


METHODS
Changes in the sensory system were prospectively followed by applying a comprehensive magnetic resonance imaging (MRI) protocol to 14 patients with subacute traumatic SCI at baseline, 2 months, 6 months, and 12 months after injury, combined with a full neurological examination and comprehensive pain assessment. Eighteen controls underwent the same MRI protocol. T1-weighted volumes, myelin-sensitive magnetization transfer saturation (MT), and longitudinal relaxation rate (R1) mapping provided data on spinal cord and brain morphometry and microstructure. Regression analysis assessed the relationship between MRI readouts and sensory outcomes.


RESULTS
At 12 months from baseline, sensory scores were unchanged and below-level neuropathic pain became prominent. Compared with controls, patients showed progressive degenerative changes in cervical cord and brain morphometry across the sensory system. At 12 months, MT and R1 were reduced in areas of structural decline. Sensory scores at 12 months correlated with rate of change in cord area and brain volume and decreased MT in the spinal cord at 12 months.


CONCLUSIONS
This study has demonstrated progressive atrophic and microstructural changes across the sensory system with a close relation to sensory outcome. Structural MRI protocols remote from the site of lesion provide new insights into neuronal degeneration underpinning sensory disturbance and have potential as responsive biomarkers of rehabilitation and treatment interventions.
Spinal Cord Injury Center Balgrist, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Patrick
P
Grabher
Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom.
Martina F
MF
Callaghan
Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom.
John
J
Ashburner
Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom.|Department of Neurophysics, Max Planck Institute for Human Cognitive, and Brain Sciences, Leipzig, Germany.
Nikolaus
N
Weiskopf
Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom.
Alan J
AJ
Thompson
Spinal Cord Injury Center Balgrist, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Armin
A
Curt
Spinal Cord Injury Center Balgrist, University Hospital Zurich, University of Zurich, Zurich, Switzerland.|Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom.|Department of Neurophysics, Max Planck Institute for Human Cognitive, and Brain Sciences, Leipzig, Germany.|Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom.
Patrick
P
Freund
D000328:Adult; D000368:Aged; D001284:Atrophy; D001921:Brain / Q000473:pathology; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009186:Myelin Sheath / Q000473:pathology; D009410:Nerve Degeneration / Q000473:pathology; D009437:Neuralgia / Q000209:etiology / Q000503:physiopathology; D010147:Pain Measurement; D011237:Predictive Value of Tests; D012678:Sensation Disorders / Q000209:etiology* / Q000473:pathology*; D013116:Spinal Cord / Q000473:pathology; D013119:Spinal Cord Injuries / Q000473:pathology* / Q000503:physiopathology; D016896:Treatment Outcome; D055815:Young Adult