Investigating Liver B0 mapping at 7T: Comparison of respiration phase, shim volume size and body shim coil arrays

Motivation: Liver scanning at 7T opens new possibilities for metabolic research with greater spatial and spectral resolution and signal-to-noise ratios. However, B0 variability at 7T provides challenges for liver scanning. The addition of body shim coil arrays has been proposed to mitigate these effects. Goal(s): Assess the impact of respiration, shim volume and shim arrays on B0 inhomogeneity in the liver at 7T. Approach: B0 maps were acquired for varying shim settings and the standard deviations within a small sample volume were calculated and compared. Results: Larger shim volumes provided more uniform B0 fields. Further work is needed to optimize surface shim coil arrays. Impact: This study provides important information about the effects of respiration, shim volume size and using body shim coil arrays in 7T liver MRI/MRS. This data can be used in future studies to optimize shim routines and improve spectral line widths.