The Enhancement of NMR/MRI Signals for Medical Imaging and Biomolecular Study.

摘要

Magnetic Resonance Imaging (MRI) has become a standard diagnostic tool in the clinical field, thanks to its non-invasive feature and superior soft tissue contrast. However, its application is still limited in many aspects, due to its intrinsically low sensitivity and the complexity of human bodies. The general aim of this dissertation is to enhance the NMR/MRI signals used for the purpose of clinical imaging and the study of macromolecules that may serve the interest of cancer treatment. In the first chapter, a brief introduction to basic NMR and MRI theory is presented. A method that holds the potential for the diagnostics of early stage disc degenerative disease is examined in Chapter 2. Aiming at one kind of polysaccharide molecule rather than the traditionally targeted water, this method provides dramatic sensitivity improvement compared to conventional techniques. Bone imaging is one of the hot areas in medical imaging research. Although many techniques have been developed, most of them require complicated pulse sequences or expensive hardware, while still suffering with limited resolutions. A new method for bone imaging is introduced in Chapter 3, although it is still in an early stage, we believe it will eventually contribute to bone imaging with better imaging contrast and resolution. It has long been known that the sensitivity of NMR signals could be enhanced with para-hydrogen hydrogenation reaction, yet this is the first time that this kind of hydrogenation is studied with a peptide (Chapter 4). Besides the expected signal enhancement, interesting phenomena such as polarization transfer and diastereoselectivity of the hydrogenation reaction are also observed. The final chapter will summarize the dissertation and discuss some future possible work.