OmniShim - a vendor-independent B0 Shimming software toolbox

Abstract

PurposeTo introduce the OmniShim Toolbox, a software package designed to calibrate and perform B0 shimming in user-defined regions of interest across systems from different vendors, supporting various shim orders. MethodsIn this study, we systematically compared the performance of vendor-implemented B0 shim routines with our custom developed OmniShim toolbox, designed to improve static magnetic field homogeneity. Single-voxel magnetic resonance spectroscopy (MRS) data were acquired from the prefrontal cortex and occipital lobe, while magnetic resonance spectroscopic imaging (MRSI) data were collected from regions above and below the corpus callosum in healthy volunteers. Measurements were conducted on both 3T and 7T MR systems to evaluate the robustness and scalability of each B0 shimming strategy across different field strengths. Additionally, functional MRI (fMRI) data were acquired at 7T to assess the impact of improved shimming on EPI data quality and BOLD contrast. ResultsThe OmniShim Toolbox demonstrated superior B0 homogeneity across all applications and field strength, leading to reduced signal dropout in fMRI and MRSI data, significantly improved spectral linewidths in SV MRS and MRSI data as well improved detection of neural networks by resting state fMRI. ConclusionThe proposed OmniShim Toolbox offers a robust and flexible approach to control B0 inhomogeneity, resulting in substantial improvements in image quality and spectral resolution. These enhancements benefit a broad range of MR applications.