Metasurface for passive RF shimming to improve brain imaging at 7T

We propose a new passive radiofrequency (RF) shimming approach using a flexible, compact, low-cost, and long-term stability metasurface to improve brain imaging at 7T. The metasurface can be manufactured as a periodic structure based on a set of metal crosses connected by the capacitors, thus having a thickness of less than 1 mm. Numerical studies with the human voxel model showed up to 6% homogeneity improvement at the regions of interest (ROI) in the presence of the metasurface in comparison with the conventional case, which also outperforms the effect of the dielectric pad’s placement.