Theory of Relaxation Times Associated with Contrast Agents in Magnetic Resonance Imaging

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This project is aimed at a first-principles understanding of the influence of paramagnetic ion systems on the relaxation times of protons of water molecules and therefore on the contrast-noise ratio for magnetic resonance imaging (MRI). The magnetic moment distributions between the paramagnetic ion and its ligands will be studied using both ab initio and approximate theoretical techniques, and the effects of these distributions on the contact and dipolar hyperfine interactions will be assessed. Systems to be studied include transition-metal and rare-earth ions, and such ions linked to protein molecules. These studies are expected to contribute to a more detailed understanding and interpretation of the biomedically important MRI technique. The images produced by MRI can be sharpened (i.e., heighten the contrast and reduce the noise) by chemical compounds containing certain metal atoms, but these may also have toxic side effects. This project is aimed at a fundamental understanding of how these compounds work to sharpen the image; appropriate non-toxic substances for administration to patients can then be devised.