Victor CARVALHO - Early-Stage Researcher - 2016 Class

Investigation of magnetization transfer in myelin using magnetic resonance imaging and spectroscopy

Magnetization transfer (MT) magnetic resonance imaging (MRI) is an in vivo imaging modality that is sensitive to the macromolecular content of biological tissues. In myelin, the wide nuclear magnetic resonance (NMR) spectrum results from dipolar coupling between the protons of the lipid chains composing myelin and is dominated by the methylene proton pair contribution. The strong dipolar interaction within the lipid methylene gives rise to dipolar order, and associated dipolar relaxation, and can be selectively detected using a modified MT sequence, named Inhomogeneous magnetization transfer (ihMT), which combines single- and dual-frequency offset off-resonance saturation. In vivo ihMT images have shown tremendous specificity for brain white matter, which is rich in myelin. The aim of this PhD thesis is to study the relation between ihMT signal and myelin content and structure, as ihMT may contribute to a better understanding of neurodegenerative disorders, such as Multiple Sclerosis (MS).

Key-words: Magnetization Transfer, Inhomogeneous Magnetization Transfer, Nuclear Magnetic Resonance, Magnetic Resonance Imaging, myelin, dipolar coupling.