Conformal Metasurface for Enhancing and Shaping Magnetic Field in 0.5T Magnetic Resonance

In recent years, mid-field Magnetic Resonance Imaging (MRI) systems have grown in popularity for several benefits, the most important being their relatively inexpensive price. In this context, maximizing the Signal-to-Noise ratio (SNR) is crucial to developing clinically useful images. Here we introduce a conformal metasurface, excited by a closely placed RF coil, able to homogenize the magnetic field distribution at the proton 1H Larmor frequency for 0.5 T brain MRI; indeed, this solution allows an improvement of the RF magnetic field transmission efficiency and, consequently, the SNR of MR scanners. The conformal structure of the proposed 5×5 metasurface is specifically designed to fit the anatomy under investigation, thus achieving greater tissue penetration and comfort for the patient. To validate the proposed approach, we performed numerical full-wave simulations by including a simplified head model, with and without the metasurface presence. Specifically, we compared the magnetic field distributions transmitted inside the phantom for different cutting planes, confirming a significant magnetic field enhancement as consequence of the presence of metasurface and demonstrating its potentialities for mid-field MRI systems.