Experimental investigation of a metasurface resonator for in vivo imaging at 1.5 T

[Display omitted] •A new metasurface has been developed for wrist imaging at 1.5 T MRI.•The metasurface can be considered as a new wireless inductively-coupled coil.•Metasurface increases the local transmit efficiency in the area of interest. In this work, we experimentally demonstrate an increase in the local transmit efficiency of a 1.5 T MRI scanner by using a metasurface formed by an array of brass wires embedded in a high permittivity low loss medium. Placement of such a structure inside the scanner results in strong coupling of the radiofrequency field produced by the body coil with the lowest frequency electromagnetic eigenmode of the metasurface. This leads to spatial redistribution of the near fields with enhancement of the local magnetic field and an increase in the transmit efficiency per square root maximum specific absorption rate in the region-of-interest. We have investigated this structure in vivo and achieved a factor of 3.3 enhancement in the local radiofrequency transmit efficiency.