Signal-to-noise ratio in diffusion-ordered spectroscopy: how good is good enough?
Signal-to-noise ratio in diffusion-ordered spectroscopy: how good is good enough?
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扩散有序光谱中的信噪比：多好才算足够好？
DOI：
10.5194/mr-2-733-2021
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Morris GA
中科院分区：
文献类型：
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作者：
Guest J;Kiraly P;Nilsson M;Morris GA
扩散有序核磁共振波谱（DOSY）通过脉冲场梯度自旋或受激回波的实验测量，构建了显示信号强度作为拉莫尔频率和扩散系数函数的多维光谱。扩散域中的峰位置由实验数据拟合到某种Stejskal-Tanner方程中估计的扩散系数决定，峰宽度由拟合过程中估计的标准误差决定。因此，DOSY光谱中扩散域的准确性和可靠性取决于实验数据中的不确定性，因此部分取决于所测实验光谱的信噪比。本文利用cram<s:1> - rao下界、蒙特卡罗方法和实验数据，研究了二维DOSY实验中信噪比、实验参数和扩散域精度之间的关系。实验结果证实，除噪声外的其他误差源对时间平均法提高扩散域精度造成了限制。
Diffusion-ordered NMR spectroscopy (DOSY) constructs multidimensional spectra displaying signal strength as a function of Larmor frequency and of diffusion coefficient from experimental measurements using pulsed field gradient spin or stimulated echoes. Peak positions in the diffusion domain are determined by diffusion coefficients estimated by fitting experimental data to some variant of the Stejskal–Tanner equation, with the peak widths determined by the standard error estimated in the fitting process. The accuracy and reliability of the diffusion domain in DOSY spectra are therefore determined by the uncertainties in the experimental data and thus in part by the signal-to-noise ratio of the experimental spectra measured. Here the Cramér–Rao lower bound, Monte Carlo methods, and experimental data are used to investigate the relationship between signal-to-noise ratio, experimental parameters, and diffusion domain accuracy in 2D DOSY experiments. Experimental results confirm that sources of error other than noise put an upper limit on the improvement in diffusion domain accuracy obtainable by time averaging.