In vivo 4.0-T magnetic resonance investigation of spinal cord inflammation, demyelination, and axonal damage in chronic-progressive experimental allergic encephalomyelitis.
OBJECTIVE
To image and dissect the lumbar spinal cord of guinea pigs with chronic-progressive experimental allergic encephalomyelitis (CP-EAE) and directly correlate the pathology to the magnetic resonance (MR) image data obtained at 4 T and determine if these MR contrasts can accurately differentiate a specific type of pathology from control tissue.


METHODS
The amount of inflammation, demyelination, and axonal pathology were quantified in the whole cord cross sections. The signal intensities (SIs) for 228 individual regions of interest (ROIs) (normal-appearing white matter (NAWM) and tissue containing inflammation with or without demyelination) were measured directly from the corresponding area on the MR images.


RESULTS
Conventional MR contrast SIs and magnetization transfer ratio (MTR) were related to the degree of demyelination and presence of inflammation. MTR and proton density-weighted (PDw) SIs were both moderately related to axonal density. The SIs for NAWM and in lesions containing both cellular infiltrates and demyelination in all conventional MR contrast images were also increased, whereas the MTR was decreased when compared to control tissue.


CONCLUSIONS
The SIs from the conventional MR contrasts and MTR at 4 T were sensitive to the presence of disease within CP-EAE spinal cord, but were not specific to the underlying pathology.
Cook
Lisa L
LL
Physiology Department, University of Western Ontario, London, Ontario, Canada.
Foster
Paula J
PJ
Mitchell
J Ross
JR
Karlik
Stephen J
SJ
D000704:Analysis of Variance; D000818:Animals; D016009:Chi-Square Distribution; D002908:Chronic Disease; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000473:pathology*; D005260:Female; D006168:Guinea Pigs; D007249:Inflammation / Q000473:pathology; D008161:Lumbosacral Region; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012372:ROC Curve; D013116:Spinal Cord / Q000473:pathology*