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Quantifying Mixing using Magnetic Resonance Imaging
Published on: January 25, 2012
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Quantifying MRI frequency shifts due to structures with anisotropic magnetic susceptibility using pyrolytic graphite
Matthew J Cronin1,2, Richard Bowtell3
1Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University Park, Nottingham, NG7 2RD, UK.
Scientific Reports
|April 21, 2018
Summary
Anisotropic magnetic susceptibility in tissues like nerves creates unexpected contrast in magnetic resonance imaging (MRI). This study validates models of field variations from anisotropic structures, improving MRI interpretation.
Area of Science:
- Physics
- Biophysics
- Medical Imaging
Background:
- Magnetic susceptibility variations in tissues are crucial for magnetic resonance imaging (MRI) contrast.
- Traditionally, isotropic magnetic susceptibility is assumed, but anisotropic susceptibility in ordered tissues like nerves and muscle causes unexpected contrast.
- Sub-voxel microstructural elements generate field variations not directly visualized in MRI.
Purpose of the Study:
- To investigate the impact of anisotropic magnetic susceptibility on MRI contrast.
- To validate theoretical models of magnetic field variations generated by anisotropic structures.
- To provide a method for directly visualizing and validating these field patterns.
Main Methods:
- Utilized pyrolytic graphite sheets with high magnetic susceptibility anisotropy.
- Fabricated structures of known geometry (slabs, spherical shells, cylindrical shells) at a scale visible in MRI.
- Mapped the resulting magnetic field variations directly using MRI.
Main Results:
- Demonstrated that anisotropic magnetic susceptibility significantly alters magnetic field patterns compared to isotropic models.
- Successfully mapped field variations from precisely engineered anisotropic structures.
- Validated theoretical expressions for field patterns generated by anisotropic materials with biologically relevant shapes.
Conclusions:
- Anisotropic magnetic susceptibility is a critical factor in MRI contrast for ordered biological tissues.
- Direct MRI visualization of field patterns from engineered anisotropic structures validates theoretical predictions.
- This work enhances understanding and interpretation of MRI contrast in biological systems.
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