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Assessment of cortical damage in early multiple sclerosis with quantitative T 2 relaxometry
Author(s) -
Gracien RenéMaxime,
Reitz Sarah C.,
Hof StephanieMichelle,
Fleischer Vinzenz,
Zimmermann Hilga,
Droby Amgad,
Steinmetz Helmuth,
Zipp Frauke,
Deichmann Ralf,
Klein Johannes C.
Publication year - 2016
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.3486
Subject(s) - cerebral cortex , cortex (anatomy) , relaxometry , pathology , clinically isolated syndrome , magnetization transfer , magnetic resonance imaging , multiple sclerosis , lesion , medicine , nuclear medicine , neuroscience , biology , radiology , psychiatry , spin echo
T 2 relaxation time is a quantitative MRI in vivo surrogate of cerebral tissue damage in multiple sclerosis (MS) patients. Cortical T 2 prolongation is a known feature in later disease stages, but has not been demonstrated in the cortical normal appearing gray matter (NAGM) in early MS. This study centers on the quantitative evaluation of the tissue parameter T 2 in cortical NAGM in a collective of early MS and clinically isolated syndrome (CIS) patients, hypothesizing that T 2 prolongation is already present at early disease stages and variable over space, in line with global and focal inflammatory processes in MS. Additionally, magnetization transfer ratio (MTR) mapping was performed for further characterization of the expected cortical T 2 alteration. Quantitative T 2 and MTR maps were acquired from 12 patients with CIS and early MS, and 12 matched healthy controls. The lesion‐free part of the cortical volume was identified, and the mean T 2 and MTR values and their standard deviations within the cortical volume were determined. For evaluation of spatial specificity, cortical lobar subregions were tested separately for differences of mean T 2 and T 2 standard deviation. We detected significantly prolonged T 2 in cortical NAGM in patients. T 2 prolongation was found across the whole cerebral cortex and in all individual lobar subregions. Significantly higher standard deviations across the respective region of interest were found for the whole cerebral cortex and all subregions, suggesting the occurrence of spatially inhomogeneous cortical damage in all regions studied. A trend was observed for MTR reduction and increased MTR variability across the whole cortex in the MS group, suggesting demyelination. In conclusion, our results suggest that cortical damage in early MS is evidenced by spatially inhomogeneous T 2 prolongation which goes beyond demyelination. Iron deposition, which is known to decrease T 2 , seems less prominent. Copyright © 2016 John Wiley & Sons, Ltd.