A Multidimensional NMR Molecular Diffusion Coupling Imaging Method

Abstract

The invention relates to a multidimensional nuclear magnetic resonance molecular diffusion coupling imaging method, which comprises the following that S1: a nuclear magnetic resonance pulse sequence is designed to realize measurement of a sample to be tested, and nuclear magnetic resonance signal acquisition of the sample to be tested is completed; S2: the acquired nuclear magnetic resonance signal is subjected to nuclear magnetic resonance data processing and analysis to obtain local voxel molecular diffusion coupling information; S3: the layer selection gradient, phase encoding gradient andfrequency encoding gradient are adjusted to obtain molecular diffusion coupling distribution of the sample to be tested under different spatial positions, and the molecular diffusion coupling distribution under all the spatial positions is reconstructed to obtain three-dimensional molecular diffusion coupling imaging results of the sample to be tested. The method of the invention avoids the problem of collecting signal difference caused by the very short relaxation time of biological tissue or material, and uses CPMG echo string in the acquisition process to add the signal amplitudes of different echoes together, and further to improve the signal to noise ratio of the signal, and to ensure the accuracy and reliability of the processing results.

Description

Technical field [0001] The invention relates to a multidimensional nuclear magnetic resonance molecular diffusion coupling imaging method, which belongs to the technical field of nuclear magnetic resonance. Background technique [0002] At present, multi-dimensional experiments in various physical methods, such as optics, neutron scattering, ultrasound, and nuclear magnetic resonance, can obtain more detailed information about the test sample by coupling and correlating corresponding physical quantities in different dimensions. In 1965, Stejeskal and Tanner established a mathematical connection between the diffusion of water molecules and the dispersion of the magnetization vector. The method they developed to measure the diffusion of water molecules has become the most classic magnetic resonance diffusion technique. By using two gradient pulses with the same size and direction, the so-called diffusion sensitive gradient pulse, the measured MR signal is compared with the MR signa...

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Problems solved by technology

[0003] However, the existing method adopts multi-diffusion and relaxation / diffusion encoding. Due to the need for diffusion editing in multiple directions, the entire experiment time is relatively long, and the acquired magnetic resonance signal is greatly affected by the relaxation time, so it is only suitable for transverse relaxation. Tissues or materials with long dwell time and insignificant internal magnetic field effect

If multidimensional diffusion and relaxation / diffusion coding sequences are combined with imaging gradients, the loss of signal will be even more pronounced, the signal-to-noise ratio will be lower, and the diffusion coefficients obtained by data processing will have large errors in all directions, resulting in low confidence in the results

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