Medical Physics, Dept. of Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Dept. of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.
Medical Physics, Dept. of Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.
J Magn Reson. 2019 Oct;307:106584. doi: 10.1016/j.jmr.2019.106584. Epub 2019 Aug 24.
The effect of anisotropic magnetic microstructure on the measurable Larmor frequency offset is investigated in media with heterogeneous magnetic susceptibility using Monte Carlo simulations. The focus is on the transition between the regimes of fast and slow diffusion of NMR-reporting molecules. Simulations demonstrate a perfect agreement with the previously developed analytic theory for fast diffusion. Beyond this regime, the frequency offset shows a pronounced dependence on the medium microarchitecture and the diffusivity of NMR-reporting spins in relation to the magnitude of the susceptibility-induced magnetic field.
利用蒙特卡罗模拟研究了各向异性磁微结构对具有不均匀磁化率的介质中可测量的拉莫尔频率偏移的影响。研究重点是在 NMR 报告分子快速和缓慢扩散的转变之间。模拟结果与之前开发的快速扩散分析理论完全吻合。超出这个范围，频率偏移与介质微结构以及与磁化率引起的磁场相比 NMR 报告自旋的扩散率有明显的关系。
