A universal B1 shim for the human cerebellum

The human cerebellum is underexplored in-vivo due to a lack of acquisition methods that effectively portray it. Its dense architecture necessitates high resolution, which benefits from 7T imaging. Unfortunately, at higher field strengths, images suffer from severely destructive B1-interference with typical coil geometries. Subject-optimized parallel-transmit approaches can mitigate B1 artifacts but increase scan-time. We designed a universal B1-shim specific to the cerebellum and immediately applicable across individuals for high-resolution 7T fMRI. We demonstrate improvements in tSNR and functional responses in cerebellar ROIs during a hand-motor task compared to a quadrature mode shim setting.