Maps of self-diffusion coefficients by radiofrequency field gradient NMR microscopy

Area of Science:

• Magnetic Resonance Imaging
• Materials Science
• Physical Chemistry

Background:

• Conventional radiofrequency field gradient methods for measuring spatially resolved diffusion coefficients yield 1D profiles modulated by spatial coordinates.
• This modulation complicates the direct acquisition of diffusion-weighted images, necessitating extensive data processing.

Purpose of the Study:

• To present a new magnetic resonance imaging (MRI) sequence that eliminates the modulation issue.
• To enable straightforward generation of true self-diffusion coefficient maps.
• To offer an alternative to conventional methods affected by background gradients.

Main Methods:

• Development of a novel MRI sequence utilizing radiofrequency field gradients.
• Implementation of a method that avoids cosine function modulation of diffusion profiles.
• Validation using phantoms and application to diverse materials like rubber, membranes, and plants.

Main Results:

• The new sequence successfully generates true self-diffusion coefficient maps without cumbersome data processing.
• Demonstrated feasibility and reliability in phantom studies.
• Successful application to complex systems including solvent-swelled rubber, membranes, and plant tissues.

Conclusions:

• The presented MRI sequence provides a direct and reliable method for mapping self-diffusion coefficients.
• This technique overcomes significant limitations of existing methods, improving diffusion imaging capabilities.
• The approach is versatile and applicable to a range of scientific and material systems.