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Updated: Jun 7, 2026
06:56
Micro/Nano-scale Strain Distribution Measurement from Sampling Moiré Fringes
Published on: May 23, 2017
The displacement correlation tensor: microstructure, ensemble anisotropy and curving fibers
Sune Nørhøj Jespersen1, Niels Buhl
1Center of Functionally Integrative Neuroscience, Aarhus University Nørrebrogade 44, Building 10G, 5th floor, Århus, Denmark. sune@cfin.au.dk
Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|November 2, 2010
Summary
The double wave vector diffusion experiment reveals pore structure and fiber curvature. This advanced diffusion MRI technique quantifies microstructural anisotropy and estimates sub-voxel fiber bending.
Area of Science:
- Magnetic Resonance Imaging
- Diffusion MRI
- Materials Science
Background:
- Standard diffusion Magnetic Resonance Imaging (dMRI) experiments provide limited information.
- Advanced dMRI techniques, such as multiple diffusion wave vector experiments, offer richer data.
- The double wave vector diffusion experiment is a specialized pulse sequence within this class.
Purpose of the Study:
- To introduce and analyze the displacement correlation tensor derived from the double wave vector diffusion experiment.
- To establish the link between the displacement correlation tensor and microstructural properties like surface-to-volume ratio and anisotropy.
- To explore novel applications of the double wave vector diffusion signal, including fiber curvature estimation.
Main Methods:
- Utilizing the cumulant expansion of the dMRI signal.
- Deriving and analyzing the displacement correlation tensor.
- Applying the Gaussian phase approximation for signal analysis.
- Employing computer simulations for validation.
Main Results:
- The short-time behavior of the displacement correlation tensor determines the surface-to-volume ratio of pore spaces.
- A general expression for the displacement correlation tensor was derived for model geometries.
- The scatter matrix, characterizing orientation distributions, is directly related to the displacement correlation tensor.
- The method accurately describes microstructural and ensemble anisotropy effects on the dMRI signal.
- The displacement correlation tensor shows potential for estimating fiber curvature and deflection angles in curving fibers.
Conclusions:
- The double wave vector diffusion experiment provides detailed microstructural information.
- The displacement correlation tensor is a powerful tool for characterizing porous media and anisotropic materials.
- This technique offers new avenues for analyzing complex microstructures and estimating fiber bending in biological tissues.
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