Metasurface-based wireless coils for magnetic resonance imaging

Abstract

Magnetic resonance imaging (MRI) is the cornerstone diagnostics technique for medicine, biology, and neuroscience. This imaging method is innovative, noninvasive and its impact continues to grow. During the past several decades the quality of MRI scans has been substantially improved through the design of very sensitive multichannel receivers and compatible receive radio-frequency (RF) coil arrays for parallel imaging. However, conventional designs of coils have already reached their “saturation point” in terms of provided signal-to-noise ratio. In this contribution unique properties of metasurfaces are used in designing new surface and volumetric wireless coils improving imaging efficiency of high-field MR systems. We employ metasurfaces organized as arrays of parallel metal wires placed close to a scanned subject inside an MRI bore to produce a wireless coil, which is driven by an external body coil via inductive coupling. The wireless coil in this approach enhances both the transmit power efficiency and the receive sensitivity of the body coil with respect to the region of interest. By full-wave numerical simulations the two metasurface-based wireless coils were compared: the surface coil using a single array of wires and the volumetric coil using two separate arrays of wires.