Homogeneous B0 coil design method for open-access ultra-low field magnetic resonance imaging: A simulation study.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Imaging

Background:

• Integrating functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) offers novel insights into brain function.
• Ultra-low-field MRI (ULF-MRI) scanners are crucial for multimodal systems, requiring static magnetic field (B0) coils that can be deactivated during MEG.
• Existing electromagnetic B0 coils face a trade-off between size and magnetic field homogeneity.

Purpose of the Study:

• To propose and design an optimized multi-stage circular coil arrangement for ULF-MRI.
• To maximize magnetic field homogeneity and minimize total wiring length.
• To achieve a compact coil design suitable for multimodal fMRI-MEG systems.

Main Methods:

• Designed a multi-stage circular coil arrangement.
• Optimized the number of coils to enhance magnetic field homogeneity.
• Minimized the total wiring length of the coils.

Main Results:

• The optimized coil arrangement has an external diameter of 600 mm and height of 600 mm, with a 600 mm diameter aperture and 300 mm height.
• Achieved magnetic field homogeneity of <100 ppm over a 210 mm diameter spherical volume.
• The new design is 1/1.9 times smaller in diameter compared to previous arrangements with similar homogeneity.

Conclusions:

• The proposed multi-stage circular coil design offers a significant reduction in size while maintaining excellent magnetic field homogeneity.
• This advancement facilitates the development of more compact and effective ULF-MRI systems for multimodal neuroscience applications.
• The design addresses key engineering challenges in integrating fMRI and MEG for enhanced brain function studies.