Highly Shielded Gradient Coil Design for a Superconducting Planar MRI System.

Area of Science:

• Medical Imaging
• Applied Physics
• Electrical Engineering

Background:

• Superconducting magnetic resonance imaging (MRI) systems utilize gradient assemblies within superconducting (SC) magnets.
• Conventional gradient coil design inadequately shields against stray fields from surrounding metal structures, causing eddy current artifacts.
• Existing methods often overlook stray fields at coil ends, compromising performance.

Purpose of the Study:

• To propose and demonstrate a novel gradient coil shielding method for planar superconducting MRI.
• To address limitations in conventional designs by considering both pole face and coil end stray fields.
• To reduce stray field leakage and mitigate eddy current artifacts in MRI systems.

Main Methods:

• Developed a new coil shielding strategy incorporating full consideration of stray fields from pole faces and coil ends.
• Applied the novel design to a 0.7T planar superconducting MRI system.
• Evaluated stray field reduction and gradient linearity.

Main Results:

• The novel design reduced maximum stray fields on the ambient structure surface by over six times for transverse coils and four times for longitudinal coils.
• Achieved highly shielded gradient coils with linear gradient fields (<5% deviation) across the imaging volume.
• Demonstrated significant improvement in stray field management compared to conventional methods.

Conclusions:

• The proposed coil shielding method effectively minimizes stray magnetic fields in planar superconducting MRI systems.
• This approach leads to a substantial reduction in eddy current artifacts, enhancing image quality.
• The developed gradient coils provide linear fields essential for accurate MRI.