Potential of Metasurface Resonators for Low-Field MRI Systems

Motivation: Although lower B0 field strength generally lead to lower SNR, metasurface resonators can greatly increase the sensitivity of scanner-integrated coils to practically perform wireless imaging. Goal(s): This work investigates the dependence of the resonance frequency on metasurface enhancements and evaluates the potential towards developments designed for low-field applications. Approach: The capabilities of three geometrically identical metasurfaces were experimentally compared at field strengths of 0.55T, 1.5T and 3T. Images were acquired using the table-integrated spine-coils. Results: The achieved SNR enhancements beneath the metasurface increased with lower field strength and were highest at 0.55T with 27-fold gain. Impact: The significant SNR gain achieved at low-field paves the way for further development and implementation of wireless metasurface technologies in MRI. As flexible and cost-effective alternatives or additions to conventional coils, they can additionally ease patient postitioning.