Effects of coplanar shielding for high field MRI

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Radiofrequency (RF) Engineering
• Medical Physics

Background:

• Traditional RF coil shielding often uses full ground planes, which can be cumbersome.
• Optimizing RF coil design is crucial for high-field MRI systems like 7T.
• Improving signal-to-noise ratio (SNR) is a key challenge in accelerating MRI acquisition.

Purpose of the Study:

• To investigate the effectiveness of a novel coplanar shielding technique for RF coils.
• To evaluate the impact of coplanar shielding on coil performance and image quality at 7T.
• To compare coplanar shielding against traditional methods in terms of SNR and g-factors.

Main Methods:

• Finite-difference time-domain (FDTD) simulations were used to determine optimal shielding parameters.
• Two coil geometries, a circular loop and a five-element array, were constructed with and without coplanar shielding.
• Bench measurements and accelerated SENSE imaging on a 7T scanner were performed to evaluate performance.

Main Results:

• Modeled and fabricated coils demonstrated good agreement, with improved Q factors.
• Coplanar shielding led to substantial improvements in signal-to-noise ratio (SNR).
• Significant reductions in g-factors were observed with the coplanar shielded array.

Conclusions:

• Coplanar shielding is an effective method for enhancing RF coil performance in 7T MRI.
• This technique offers substantial improvements in SNR and g-factors, facilitating accelerated imaging.
• Coplanar shielding presents a promising alternative to traditional shielding methods for high-field MRI applications.