Proton Magnetic Resonance of Biological Systems

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Nuclear magnetic resonance (NMR), with its combined sensitivity to both structure and dynamics, is a well-proven technique for the study of biological systems. Since life processes occur in solution, the proton NMR of water in these systems should contain important information. Indeed, medical magnetic resonance imaging (MRI) relies on the exquisite contrast provided by differences in signal from tissue water between different types of normal tissue and between normal and pathological tissue. However, our understanding of the fundamental origins of this exquisite MR contrast is still at a primitive stage. At present our research is focused on brain and spine tissue in humans and animal models of human tissue. Our research program has three main themes: 1) exploring the fundamental mechanisms responsible for the nature of the magnetic resonance (MR) signal (or MRI contrast). 2) developing and optimising MR techniques which exploit the fundamental mechanisms to create unique contrasts and 3) application of these MR techniques to better understand normal and abnormal human tissue structure and function.  For the past two decades, our research group has worked on the measurement of myelin content non invasively by MRI. We pioneered the in vivo measurement of the myelin water fraction (the faction of signal from myelin water) which promises to provide an accurate in vivo MR measure of myelin. Myelin, which insulates neurons in brain, accelerates nerve signal conduction rates by two orders of magnitude and when myelin is damaged there are clinical deficits. Myelin plays a large role in how the brain works, consequently, much research has been dedicated to finding techniques for imaging myelin in humans in vivo. OBJECTIVES of this NSERC Discovery Grant Research Program:  1) To better understand myelin water imaging by characterising the fundamental mechanisms, particular the role of magnetization exchange.  2) To explore the mechanisms behind other magnetic resonance techniques which have been proposed to measure myelin in vivo – mcDESPOT and inhomogeneous MT.  3) To further optimise the myelin water imaging technique by reducing scan time and increasing signal to noise 4) To further understand the role of myelination in normal brain and spine function  The research will be carried out in two locations: UBC Physics where we shall use a NMR spectrometer to study ex vivo bovine (cow) brain and samples which model brain; and UBC Radiology where we shall study normal human brain and spine. This research will result in improvements to MRI techniques for measuring brain and spine myelination. The ability to measure myelin accurately will enable assessment of the efficacy of drugs designed to protect the brain from demyelination or to induce remyelination in abnormal brain. It will also aid in characterizing the role of myelination in normal brain and many neurological diseases, for example, multiple sclerosis.