An Improved Two- Dimensional Inversion Algorithm for Low-Field NMR Diffusion- Transverse Relaxation Correlation Data

Abstract

Abstract:

NMR spectra acquired at low field often show severe signal overlap. Under such circumstance, two-dimensional (2D) diffusion-transverse relaxation (D-T₂) correlation data are useful to differentiate signals from different components in the sample. The currently available inversion algorithms for D-T₂ correlation data are time- and memory-consuming. To overcome this problem, we developed an improved 2D D-T₂ inversion algorithm, which is more effective and consumes less memory and time than the traditional inversion algorithms. In brief, the logarithm values of discrete diffusion coefficient and transverse relaxation time were first obtained and used to construct two core matrices according to the signal collection conditions. Singular value decomposition was then carried out for the two matrices, followed by application of a cutoff value to remove negligible values. The inverse matrices of the thresholded core matrices were calculated and used to derive the initial inversion result. Finally, the initial inversion results were iterated with non-negative constraints to derived the final inversion results.

Key words: nuclear magnetic resonance, diffusion, transverse relaxation, two-dimensional inversion

CLC Number:

TP391. 9

LI Xin-jun1，NIE Sheng-dong1*，WANG Yuan-jun1，YANG Pei-qiang2. An Improved Two- Dimensional Inversion Algorithm for Low-Field NMR Diffusion- Transverse Relaxation Correlation Data[J]. Chinese Journal of Magnetic Resonance.

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