Open-Source, Multi-Vendor B0 Shimming Protocol

Motivation: Harmonize the B0 shimming prescan step for multi-site fMRI and MRI studies. Goal(s): Create an open-source, multi-vendor B0 shimming protocol with equivalent performance to vendors' shimming methods. Approach: We calibrate shim coil effects to a spherical harmonic basis and use regularized field maps to solve for shim coefficients to improve B0 homogeneity. We compared whole-brain field maps before and after applying our shim tool to both GE and Siemens built-in shimming protocols. We also compare the performance of our tool for the brainstem region. Results: Our protocol can be run on both vendors and performs similarly to vendor protocols. Impact: The proposed open-source B0 shimming protocol runs on multiple vendors' scanners, increasing the harmonization of experimental workflows for multisite MRI and fMRI studies.