Rapid ∆B0 Field Mapping for Real-Time Shimming of Human Brain

Motivation: High-quality MRI demands accurate ∆B0 field mapping. Traditional field mapping methods cannot address motion-induced susceptibility changes during acquisition. A rapid navigator can achieve real-time motion correction with accurate shim and frequency updates. Goal(s): Develop a rapid navigator to achieve accurate field maps for real time motion correction applications. Approach: We developed GRAPPA accelerated dual-echo EPI-vNavs of rapid ∆B0 field mapping. We compared field mapping and shim current accuracy of vNavs at different resolutions and accelerations to 3D-GRE in scanner-based 2SH and multi-coil shimming. Results: The field maps generated with accelerated vNavs closely matched 3D-GRE field maps and accurately determined shim currents. Impact: Accelerated dual-echo EPI vNavs provide rapid, accurate field mapping, reducing feedback delays. This research provides valuable insights into impact of acceleration and resolution in vNav-based field mapping, to benefit various MRI applications in mitigating susceptibility artifacts arising from motion-induced changes.