T₂ selective π Echo-Planar Imaging for porous media MRI

Area of Science:

• Magnetic Resonance Imaging
• Materials Science
• Physics

Background:

• Proton density imaging using Echo Planar Imaging (PEPI) can characterize fluids in porous media.
• Distinguishing multiple T2 relaxation components within image voxels is crucial for detailed analysis.
• Existing methods may lack the specificity to resolve diverse fluid properties.

Purpose of the Study:

• To explore T2-selective imaging using adiabatic inversion preparation with PEPI readout.
• To develop a method for discriminating multiple T2 components in porous media.
• To generate spatially resolved T2 distributions for enhanced characterization.

Main Methods:

• Utilized adiabatic inversion as a magnetization preparation sequence prior to PEPI readout.
• Employed Bloch equation simulations to predict responses of different species to inversion pulses.
• Acquired images with and without inversion pulses to isolate relaxation components.
• Introduced T2 weighting by adjusting spatial encoding gradients within the PEPI sequence.
• Extracted T2 decay curves voxel-wise from a series of T2-weighted images.

Main Results:

• Successfully implemented T2-selective imaging with PEPI for porous media.
• Demonstrated the ability to acquire different relaxation components by combining prepared and unprepared images.
• Generated spatially resolved T2 distributions by analyzing T2 decay curves.
• Achieved remarkable agreement between the results of the two tested methods.

Conclusions:

• The developed T2-selective PEPI method reliably discriminates multiple fluid components in porous media.
• This technique enables detailed characterization of fluid properties through spatially resolved T2 distributions.
• While reliable, the method's current implementation is noted to be slow, suggesting avenues for future optimization.