Evaluation of the pathologic characteristics of excitotoxic spinal cord injury with MR imaging.
OBJECTIVE
Although high-resolution MR imaging is a valuable diagnostic tool, in vivo MR imaging has not yet been compared with in vitro MR imaging and histologic techniques following experimental spinal cord injury (SCI). The goal of the present study was to evaluate the feasibility of using in vivo MR imaging, in vitro MR imaging, and histologic techniques to study pathologic changes associated with excitotoxic SCI at a single time point. These results are important for future research using in vivo MR imaging to study the temporal profile of pathologic changes following SCI.


METHODS
Rats received intraspinal injections of quisqualic acid at the T12-L2 spinal level. In vivo T1- and T2-weighted and dynamic contrast-enhanced MR images were collected 17-24 days postinjury. Once completed, spinal cords were removed and in vitro MR microscopy and histologic assessment were performed. MR images were collected using 4.7-T (in vivo) and 14.1-T magnets (in vitro).


RESULTS
Pathologic changes--including hemorrhage, neuronal loss, cavities, and central canal expansion--were visible in T2-weighted in vivo MR images. Evaluation of the blood-spinal cord barrier after injury with contrast agent enhancement showed no disruption at the time points evaluated. In vitro MR images and histologic evaluation confirmed pathologic details observed in vivo.


CONCLUSIONS
Results show that high-resolution in vivo MR imaging has the potential to be used in studying the progression of pathologic changes at multiple time points following SCI. This strategy may provide a way of studying structure-function relationships between therapeutic interventions and different pathologic characteristics of the injured spinal cord.
Berens
Sara A
SA
Comprehensive Center for Pain Research, University of Florida, Gainesville, FL, USA.
Colvin
Daniel C
DC
Yu
Chen-Guang
CG
Yezierski
Robert P
RP
Mareci
Thomas H
TH
D000818:Animals; D002199:Capillary Permeability; D018690:Excitatory Amino Acid Agonists / Q000008:administration & dosage; D005240:Feasibility Studies; D006470:Hemorrhage / Q000139:chemically induced / Q000473:pathology; D007278:Injections, Spinal; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D016318:Quisqualic Acid / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000098:blood supply / Q000473:pathology*; D013118:Spinal Cord Diseases / Q000139:chemically induced* / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology
D018690:Excitatory Amino Acid Agonists; D016318:Quisqualic Acid