NMR measurement of self-diffusion coefficients by slice selection

Area of Science:

• Magnetic Resonance Imaging
• Physical Chemistry

Background:

• Traditional inversion-recovery experiments typically analyze the entire sample's longitudinal nuclear magnetization.
• The region of interest is usually defined by the transmitting-receiving coil's limits.

Purpose of the Study:

• To investigate the effects of spatially limiting the region of interest to a thin slice in inversion-recovery experiments.
• To explore the use of magnetic field gradients for slice selection in these experiments.
• To develop novel methods for measuring molecular self-diffusion coefficients.

Main Methods:

• Utilized radio-frequency (B(1)) field gradients for slice selection.
• Developed novel procedures leveraging the natural inhomogeneity of the B(1) field from a saddle coil.
• Theoretically accounted for molecular self-diffusion effects on magnetization recovery within the selected slice.

Main Results:

• Demonstrated that molecular self-diffusion influences magnetization recovery when the region of interest is confined to a thin slice.
• Experimental observations of self-diffusion effects were successfully explained by an appropriate theory.
• The proposed approach allows for straightforward physical assessment of these phenomena.

Conclusions:

• Spatially limiting the region of interest in inversion-recovery experiments provides insights into molecular self-diffusion.
• Novel methods using B(1) gradients offer a new avenue for measuring self-diffusion coefficients.
• This technique enhances the versatility of magnetic resonance methods for studying molecular dynamics.