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Evidence of demyelination in mild cognitive impairment and dementia using a direct and specific magnetic resonance imaging measure of myelin content
Author(s) -
Bouhrara Mustapha,
Reiter David A.,
Bergeron Christopher M.,
Zukley Linda M.,
Ferrucci Luigi,
Resnick Susan M.,
Spencer Richard G.
Publication year - 2018
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2018.03.007
Subject(s) - dementia , myelin , magnetic resonance imaging , magnetization transfer , vascular dementia , biomarker , medicine , psychology , white matter , neuroscience , pathology , disease , chemistry , radiology , central nervous system , biochemistry
We investigated brain demyelination in aging, mild cognitive impairment (MCI), and dementia using a direct magnetic resonance imaging marker of myelin. Methods Brains of young and old controls, and old subjects with MCI, Alzheimer's disease, or vascular dementia were scanned using our recently developed myelin water fraction (MWF) mapping technique, which provides greatly improved accuracy over previous comparable methods. Maps of MWF, a direct and specific myelin measure, and relaxation times and magnetization transfer ratio, indirect and nonspecific measures, were constructed. Results MCI subjects showed decreased MWF compared with old controls. Demyelination was greater in Alzheimer's disease or vascular dementia. As expected, decreased MWF was accompanied by decreased magnetization transfer ratio and increased relaxation times. The young subjects showed greater myelin content than the old subjects. Discussion We believe this to be the first demonstration of myelin loss in MCI, Alzheimer's disease, and vascular dementia using a method that provides a quantitative magnetic resonance imaging–based measure of myelin. Our findings add to the emerging evidence that myelination may represent an important biomarker for the pathology of MCI and dementia. This study supports the investigation of the role of myelination in MCI and dementia through use of this quantitative magnetic resonance imaging approach in clinical studies of disease progression, and relationship of functional status to myelination status. Furthermore, mapping MWF may permit myelin to serve as a therapeutic target in clinical trials.