Development and application of quantitative MRI methods for assessing white matter integrity in the mouse brain

التفاصيل البيبلوغرافية
العنوان: Development and application of quantitative MRI methods for assessing white matter integrity in the mouse brain
المؤلفون: Thiessen, Jonathan
المساهمون: Martin, Melanie (Physics and Astronomy), Gericke, Michael (Physics and Astronomy) King, Scott (Physics and Astronomy) Gough, Kathy (Chemistry) Kozlowski, Piotr (Physics and Astronomy, University of British Columbia)
سنة النشر: 2012
المجموعة: Theses Canada / Thèses Canada (Library and Archives Canada)
مصطلحات موضوعية: magnetic resonance imaging, diffusion tensor imaging, magnetization transfer imaging, relaxometry, demyelination, cuprizone, corpus callosum, myelin, electron microscopy, multiple sclerosis, white matter, image processing
الوصف: Healthy white matter in the brain and spinal cord is composed primarily of myelinated axons and glial cells. Myelinated axons transfer information between the peripheral nervous system and the central nervous system (CNS) as well as between centres within the CNS. Demyelination, a hallmark of neurodegenerative autoimmune diseases such as multiple sclerosis (MS), can cause nerve damage and degrade signal propagation. Magnetic resonance imaging (MRI) methods thought to assess myelin integrity and the structural integrity of axons are improving both the diagnosis and understanding of white matter diseases such as MS. Current methods, however, are sensitive to many different pathologies, making the interpretation of individual MRI results difficult. For this dissertation, several quantitative MRI methods were developed and compared, including single component T1 and T2 relaxometry, multicomponent T2 relaxometry, diffusion tensor imaging (DTI), and quantitative magnetization transfer imaging (qMTI). These methods were tested on agarose gels, fixed rat spinal cords, healthy control mice, and the cuprizone mouse model of demyelination. Quantitative MRI measurements were correlated to ultrastructural measurements of white matter to determine the influence myelin content and axonal structure have on different MRI methods. Cellular distributions measured in electron micrographs of the corpus callosum correlated strongly to several different quantitative MRI metrics. The largest Spearman correlation coefficient varied depending on cellular type: longitudinal relaxation rates (RA/T1) vs. the myelinated axon fraction ( r = 0.90/-0.90), the qMTI-derived bound pool fraction (f) vs. the myelin sheath fraction ( r = 0.93), and the DTI-derived axial diffusivity vs. the non-myelinated cell fraction (r = 0.92). Using Pearson’s correlation coefficient, f was strongly correlated to the myelin sheath fraction (r = 0.98) with a linear equation predicting myelin content (5.37f −0.25). Of the calculated MRI metrics, f was the strongest ...
نوع الوثيقة: other/unknown material
اللغة: unknown
العلاقة: http://hdl.handle.net/1993/9221Test
الإتاحة: http://hdl.handle.net/1993/9221Test
رقم الانضمام: edsbas.75B1141F
قاعدة البيانات: BASE