Extended arrays for nonlinear susceptibility magnitude imaging

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Materials Science

Background:

• Nonlinear susceptibility magnitude imaging (SMI) is an emerging technique for visualizing material properties.
• Previous work established pilot-scale feasibility, necessitating larger-scale demonstrations.

Purpose of the Study:

• To implement and evaluate an enhanced nonlinear SMI system with a larger coil array and field-of-view.
• To assess the feasibility of extending SMI for complex imaging patterns and medical applications.

Main Methods:

• Utilized multifrequency intermodulation and phase encoding for nonlinear SMI.
• Constructed a hexagonal 61-voxel grid with 3.5-mm diameter wells containing Fe3O4 magnetic nanoparticles (mNPs).
• Configured imaging hardware with three excitation and three detection coils.

Main Results:

• Successfully imaged hexagonal and bar patterns of mNPs with high fidelity (R2>0.9) across orientations.
• Demonstrated effective phase encoding and imaging of reduced mNP sample sizes.
• Validated the feasibility of extending the nonlinear SMI method beyond pilot scale.

Conclusions:

• Nonlinear SMI with enhanced hardware and complex patterns is feasible.
• The demonstrated system shows significant promise for future development into practical medical imaging solutions.