Gradiometer pick-up coil design for a low field SQUID-MRI system

Area of Science:

• Medical Imaging
• Low-Field MRI
• Superconducting Devices

Background:

• Improving signal-to-noise ratio (SNR) is crucial for enhancing magnetic resonance imaging (MRI) quality, especially at low magnetic field strengths.
• Traditional MRI systems face challenges with interference and system interactions that can degrade image quality.

Purpose of the Study:

• To investigate the use of liquid helium-cooled gradiometer coils and a DC superconducting quantum interference device (SQUID) preamplifier for improving MRI SNR at 0.01 T.
• To evaluate the effectiveness of axial and planar (figure-of-eight) gradiometer configurations in reducing system interactions and rejecting interference.

Main Methods:

• Utilized liquid helium-cooled (4.2 K) gradiometer coils and a DC SQUID preamplifier.
• Tested both axial and planar (figure-of-eight) gradiometer configurations.
• Performed MRI on a human arm using the developed system.

Main Results:

• The system successfully improved the SNR of MRI at 0.01 T.
• Gradiometer windings effectively reduced lossy interactions with room temperature components and rejected distant interference.
• The figure-of-eight gradiometer demonstrated a trade-off between sensitivity fall-off and improved interference rejection.

Conclusions:

• Liquid helium-cooled gradiometer coils and SQUID preamplifiers offer a viable method for enhancing low-field MRI performance.
• Gradiometer configurations can be optimized to balance sensitivity and interference rejection for improved SNR.
• The developed system shows potential for practical applications in low-field MRI, as demonstrated by human arm imaging.