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

该项目旨在从第一性原理上理解顺磁离子系统对水分子质子弛豫时间的影响，从而对磁共振成像(MRI)的对比度噪声比的影响。我们将用从头算和近似理论方法研究顺磁离子与其配体之间的磁矩分布，并评估这些分布对接触和偶极超精细相互作用的影响。将要研究的体系包括过渡金属离子和稀土离子，以及与蛋白质分子相连的此类离子。这些研究有望有助于更详细地理解和解释具有重要生物医学意义的核磁共振成像技术。核磁共振产生的图像可以通过含有某些金属原子的化合物来锐化(即提高对比度和降低噪音)，但这些化合物也可能有毒副作用。这个项目的目的是从根本上了解这些化合物是如何工作的，以提高图像的清晰度；然后可以设计出适当的无毒物质来给患者服用。

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.