Development of a Helmet-Shape Dual-Channel RF coil for brain imaging at 54 mT using inverse boundary element method

Area of Science:

• Medical Imaging
• Biophysics
• Electrical Engineering

Background:

• Very-low field (VLF) magnetic resonance imaging (MRI) presents advantages in size, cost, and shielding but struggles with low signal-to-noise ratio (SNR).
• Optimizing radio frequency (RF) receive coils is critical for enhancing SNR in VLF MRI systems operating below 100 mT.

Purpose of the Study:

• To design and optimize a helmet-shaped, dual-channel RF receive coil for VLF brain MRI at 54 mT (2.32 MHz).
• To improve SNR and diagnostic potential in VLF MRI applications.

Main Methods:

• Utilized the inverse boundary element method (IBEM) for initial coil design and wiring, incorporating regularization terms for optimization.
• Determined optimal loop counts (9 axial, 8 radial) through theoretical modeling and physical AC resistance measurements.
• Validated the dual-channel coil's performance using phantom and in-vivo human brain imaging.

Main Results:

• The designed dual-channel RF coil achieved a 16-25% increase in SNR compared to single-channel coils in in-vivo brain imaging.
• Achieved high-quality T1, T2-weighted, and FLAIR images, demonstrating diagnostic potential.
• Observed slightly poorer B1 homogeneity with the dual-channel coil.

Conclusions:

• The developed helmet-shaped dual-channel RF coil effectively enhances SNR in VLF MRI brain imaging.
• The inverse problem approach provides an adaptable methodology for customizing RF coil designs for specific VLF MRI requirements.
• This advancement holds promise for improved diagnosis in neurological conditions like stroke and trauma.