Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, New York, NY, USA.
Radiology, Columbia University College of Physicians and Surgeons, New York, NY, USA.
NMR Biomed. 2021 May;34(5):e4129. doi: 10.1002/nbm.4129. Epub 2019 Jul 17.
The aim of this study was to develop a novel software platform for the simulation of magnetic resonance spin systems, capable of simulating a large number of spatial points (128 ) for large in vivo spin systems (up to seven coupled spins) in a time frame of the order of a few minutes. The quantum mechanical density-matrix formalism is applied, a coherence pathway filter is utilized for handling unwanted coherence pathways, and the 1D projection method, which provides a substantial reduction in computation time for a large number of spatial points, is extended to include sequences of an arbitrary number of RF pulses. The novel software package, written in MATLAB, computes a basis set of 23 different metabolites (including the two anomers of glucose, seven coupled spins) with 128 spatial points in 26 min for a three-pulse experiment on a personal desktop computer. The simulated spectra are experimentally verified with data from both phantom and in vivo MEGA-sLASER experiments. Recommendations are provided regarding the various assumptions made when computing a basis set for in vivo MRS with respect to the number of spatial points simulated and the consideration of relaxation.
本研究的目的是开发一种新的磁共振自旋系统模拟软件平台，能够在几分钟的时间框架内模拟大量的空间点（多达 128 个）的大的活体自旋系统（多达七个耦合自旋）。应用量子力学密度矩阵形式，利用相干途径滤波器来处理不需要的相干途径，并将提供大量空间点计算时间大大减少的 1D 投影方法扩展到包括任意数量的射频脉冲序列。新的 MATLAB 编写的软件包可在个人台式计算机上对三脉冲实验计算具有 128 个空间点的 23 种不同代谢物（包括葡萄糖的两个差向异构体、七个耦合自旋）的基集，耗时 26 分钟。模拟谱与来自幻影和体内 MEGA-sLASER 实验的数据进行了实验验证。针对活体 MRS 计算基集时有关模拟的空间点数量和弛豫考虑的各种假设，提供了建议。
