A simulation based method to assess inversion algorithms for transverse relaxation data
A simulation based method to assess inversion algorithms for transverse relaxation data
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DOI：
10.1016/j.jmr.2007.12.021
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发表时间：
2008-04-01
影响因子：
2.2
通讯作者：
Pan, Yong
中科院分区：
文献类型：
--
作者：
Ghosh, Supriyo;Keener, Kevin M.;Pan, Yong
核磁共振弛豫法是理解复杂多相体系中各种化学和物理现象的一种非常有用的工具。A Carr-Purcell-Meiboom-Gill（CPMG）[P.T. Callaghan，《核磁共振显微镜原理》，克拉伦登出版社，牛津，199 1]实验是一种在低场中获得横向驰豫常数（T-2）的简单而快速的方法。大多数样本通常具有T1值的分布。从嘈杂的衰变数据中提取T-2S的这种分布本质上是一个不适定的逆问题。迄今为止，已使用各种反演方法来解决这个问题。使用反演算法的一个主要问题是确定计算的分布有多精确。本文系统地分析了一种反演算法UPEN [G.C.波吉亚，RJS。Brown，P. Fantazzini，多指数衰减数据的均匀惩罚反演，磁共振杂志132（1998）65-77; G.C.波吉亚，RJS。布朗，P. Fantazzini。多指数衰减数据的均匀惩罚反演2。Data spacing，T2 data，systematic data errors，and diagnostics，Journal of Magnetic Resonance 147（2000）273-285]通过模拟CPMG数据生成进行。通过我们的模拟技术和统计分析，评估了各种实验参数对计算分布的影响。我们通过匹配一系列真实衰变数据和一个有噪声的模拟数据的反演结果来收敛到真实分布。除了模拟研究，同样的方法也适用于真实的实验数据，以支持模拟结果。(c)2008年爱思唯尔公司All rights reserved.
NMR relaxometry is a very useful tool for understanding various chemical and physical phenomena in complex multiphase systems. A Carr-Purcell-Meiboom-Gill (CPMG) [P.T. Callaghan, Principles of Nuclear Magnetic Resonance Microscopy, Clarendon Press, Oxford, 199 1] experiment is an easy and quick way to obtain transverse relaxation constant (T-2) in low field. Most of the samples usually have a distribution of T, values. Extraction of this distribution of T-2S from the noisy decay data is essentially an ill-posed inverse problem. Various inversion approaches have been used to solve this problem, to date. A major issue in using an inversion algorithm is determining how accurate the computed distribution is. A systematic analysis of an inversion algorithm, UPEN [G.C. Borgia, R.J.S. Brown, P. Fantazzini, Uniform-penalty inversion of multiexponential decay data, Journal of Magnetic Resonance 132 (1998) 65-77; G.C. Borgia, R.J.S. Brown, P. Fantazzini. Uniform-penalty inversion of multiexponential decay data II. Data spacing, T2 data, systematic data errors, and diagnostics, Journal of Magnetic Resonance 147 (2000) 273-285] was performed by means of simulated CPMG data generation. Through our simulation technique and statistical analyses, the effects of various experimental parameters on the computed distribution were evaluated. We converged to the true distribution by matching up the inversion results from a series of true decay data and a noisy simulated data. In addition to simulation studies, the same approach was also applied on real experimental data to support the simulation results. (c) 2008 Elsevier Inc. All rights reserved.