Year: 2000
Type: dissertation
Abstract: Magnetization transfer (MT) imaging is a relatively new magnetic resonance imaging (MRI) technique that generates contrast dependent upon the phenomenon of magnetization exchange between semi-solid macromolecular protons and water protons. This technique has the ability to indirectly image semi-solids, such as protein matrices and cell membranes, whose magnetization dies away too quickly to be imaged directly. Preliminary in vitro and in vivo results suggest that MT quantification may allow improved characterization of the pathologically heterogeneous lesions of multiple sclerosis (MS) by providing a measure of demyelination. However, MT imaging, as currently applied, is only a semi-quantitative technique that reflects a complex combination of tissue and experimental parameters in addition to MT. In this thesis a novel quantitative imaging technique is described that yields all of the observable properties of the binary spin bath model for MT. Based on a new model of the steady-state behavior of the magnetization during a pulsed MT weighted imaging sequence, as well as new methodological developments in MRI relaxometry, this approach yields parametric images of the fractional size of the restricted pool, the magnetization exchange rate, the T2 of the restricted pool and the relaxation times in the free pool. Validated experimentally on agar gels and samples of uncooked beef, the method is demonstrated in studies of two normal subjects and a patient with multiple sclerosis.
Source: eScholarship@McGill (McGill)
DOI: 10.82308/8031
Author: Sled, John G.
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2189396106