In vivo histology of the myelin g-ratio with magnetic resonance imaging.
Neuroimage
; 118: 397-405, 2015 Sep.
Article
em En
| MEDLINE
| ID: mdl-26004502
ABSTRACT
The myelin g-ratio, defined as the ratio between the inner and the outer diameter of the myelin sheath, is a fundamental property of white matter that can be computed from a simple formula relating the myelin volume fraction to the fiber volume fraction or the axon volume fraction. In this paper, a unique combination of magnetization transfer, diffusion imaging and histology is presented, providing a novel method for in vivo magnetic resonance imaging of the axon volume fraction and the myelin g-ratio. Our method was demonstrated in the corpus callosum of one cynomolgus macaque, and applied to obtain full-brain g-ratio maps in one healthy human subject and one multiple sclerosis patient. In the macaque, the g-ratio was relatively constant across the corpus callosum, as measured by both MRI and electron microscopy. In the human subjects, the g-ratio in multiple sclerosis lesions was higher than in normal appearing white matter, which was in turn higher than in healthy white matter. Measuring the g-ratio brings us one step closer to fully characterizing white matter non-invasively, making it possible to perform in vivo histology of the human brain during development, aging, disease and treatment.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Axônios
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Encéfalo
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Imagem de Difusão por Ressonância Magnética
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Bainha de Mielina
Limite:
Adult
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Animals
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Humans
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Male
Idioma:
En
Revista:
Neuroimage
Assunto da revista:
DIAGNOSTICO POR IMAGEM
Ano de publicação:
2015
Tipo de documento:
Article