T₁ relaxation and inhomogeneous magnetization transfer in brain : physics and applications
department or school: Science, Faculty of
department or school: Physics and Astronomy, Department of
data provider: DSpace
degree campus: UBCV
creator: Manning, Alan Patrick
issued: 2019-01-03T17:11:02Z
issued: 2018
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: A major goal of the Magnetic Resonance Imaging (MRI) community is quantifying myelin in white matter. MRI contrast depends on tissue microstructure, so quantitative models require detailed understanding of Nuclear Magnetic Resonance (NMR) physics in white matter's complex, heterogeneous environment. In this thesis, we study the underlying physics behind two different ¹H contrast mechanisms in white and grey matter tissue: T₁ relaxation and the recently developed inhomogeneous Magnetization Transfer (ihMT). Using ex-vivo white and grey matter samples of bovine brain, we performed a comprehensive solid-state NMR study of T₁ relaxation under six diverse initial conditions. For the first time, we used lineshape fitting to quantify the non-aqueous magnetization during relaxation. A four pool model describes our data well, matching with earlier studies. We also show examples of how the observed T₁ relaxation behaviour depends upon the initial conditions. ihMT's sensitivity to lipid bilayers, like those in myelin, was originally thought to rely upon hole-burning in the supposedly inhomogeneously-broadened lipid lineshape. Our work shows that this is incorrect and that ihMT only requires the presence of dipolar couplings, not a specific kind of line broadening. We developed a simple explanation of ihMT using a spin-1 system. Using solid-state NMR, we then performed measurements of ihMT and T₁D (dipolar order relaxation time) on four samples: a multilamellar lipid system (Prolipid-161), wood, hair, and bovine tendon. ihMT was observed in all samples, even those with homogeneous broadening (wood and hair). Moreover, we saw no evidence of hole-burning. Lastly, we present results from ihMT experiments with CPMG acquisition on the bovine brain samples. We show that myelin water has a higher ihMT signal than water outside the myelin. It was determined that this was due to the unique thermal motion in myelin lipids. In doing so, we developed a useful metric for determining the rel…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/68152
note: T1 Relaxation and Inhomogeneous MagnetizationTransfer in Brain: Physics and ApplicationsbyAlan Patrick ManningB.Sc., Carleton University, 2011M.Sc., The University of British Columbia, 2013A THESIS SUBMITTED IN PARTIAL FULFILLMENTOF THE REQUIREMENTS FOR THE DEGREE OFDoctor of PhilosophyinTHE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES(Physics)THE UNIVERSITY OF BRITISH COLUMBIA(Vancouver)December 2018© Alan Patrick Manning, 2018The following individuals certify that they have read, and recommend to the Faculty ofGraduate and Postdoctoral Studies for acceptance, the dissertation entitled:T1 Relaxation and Inhomogeneous Magnetization Transfer in Brain: Physics and Applicationssubmitted by Alan Manning in partial fulfillment of the requirements forthe degree of Doctor of Philosophyin PhysicsExamining Committee:Carl Michal, Department of Physics & AstronomyResearch SupervisorAlex MacKay, Department of Physics & Astronomy and Department of RadiologyCo-SupervisorSteven Plotkin, Department of Physics & AstronomySupervisory Committee MemberPiotr Kozlowski, Department of Radiology and Department of Urological SciencesSupervisory Committee MemberElliot Burnell, Department of Chemistry (Emeritus)University ExaminerLawrence McIntosh, Department of Chemistry and Department of Biochemistry & Molecular Bi-ologyUniversity ExaminerHarald E. Möller, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig; andFelix Bloch Institute for Solid State Physics, University of LeipzigExternal ExamineriiAbstractA major goal of the Magnetic Resonance Imaging (MRI) community is quantifying myelin inwhite matter. MRI contrast depends on tissue microstructure, so quantitative models requiredetailed understanding of Nuclear Magnetic Resonance (NMR) physics in white matter’scomplex, heterogeneous environment. In this thesis, we study the underlying physics behindtwo different 1H contrast mechanisms in white and grey matter tissue: T1 relaxation and therecently developed inhomogeneous Ma…
has type: Thesis/Dissertation
date issued: 2019-02
is shown at: 10.14288/1.0375841
language: eng
degree discipline: Physics
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-ShareAlike 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-sa/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/68152