Pathological correlates of magnetic resonance imaging texture heterogeneity in multiple sclerosis.
OBJECTIVE
To analyze the texture of T2-weighted magnetic resonance imaging (MRI) of postmortem multiple sclerosis (MS) brain, and to determine whether and how MRI texture correlates with tissue pathology.


METHODS
Ten brain samples from 3 subjects with MS were examined. Areas of complete, partial, or no loss of Luxol fast blue (myelin) and Bielschowsky (axons) staining were marked on histological images, and matched on corresponding MRI as lesions, diffusely abnormal white matter (DAWM), and normal-appearing white matter (NAWM). The number of CD45(+) cells (inflammation) was also counted. MRI texture was computed using polar Stockwell transform and compared to histology.


RESULTS
Thirty-four lesions, 17 DAWM regions, and 36 NAWM regions were identified. After mixed effects modeling, MRI texture heterogeneity was greater in lesions than in DAWM (p < 0.001) and NAWM (p < 0.001), and was greater in DAWM than in NAWM (p < 0.001); the number of CD45+ cells was greater in both lesions (p < 0.001) and DAWM (p = 0.005) than in NAWM. In MRI, a gradient of texture heterogeneity was detected in lesions, with gradual tapering toward perilesional NAWM. Moreover, besides univariate correlation with histological markers, texture heterogeneity correlated independently with normalized myelin density (p < 0.01) when random effects were considered. Within sample, MRI texture correlated with myelin and axonal density in 7 of 10 samples (p < 0.01).


CONCLUSIONS
Texture analysis performed on routine clinical magnetic resonance images may be a potential measure of tissue integrity. Tissues with more severe myelin and axonal pathology are associated with greater texture heterogeneity.
Department of Radiology, University of Calgary, Calgary, Alberta; Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta.
Yunyan
Y
Zhang
G R Wayne
GR
Moore
Cornelia
C
Laule
Thorarin A
TA
Bjarnason
Piotr
P
Kozlowski
Anthony
A
Traboulsee
David K B
DK
Li
D000328:Adult; D001369:Axons / Q000378:metabolism / Q000473:pathology; D001921:Brain / Q000473:pathology*; D002452:Cell Count; D005260:Female; D006801:Humans; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000473:pathology*; D009186:Myelin Sheath / Q000473:pathology; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009474:Neurons / Q000473:pathology; D055815:Young Adult
D017493:Leukocyte Common Antigens