A stitching method for dynamic field monitoring using NMR probes: validation in simulation and human experiments

Motivation: Last year we proposed and demonstrated a stitching method that can be used to characterize sequences with higher resolution or longer readout. Goal(s): To validate our stitching method by image reconstruction based on an extended signal model using simulation and real data experiments. Approach: Image reconstruction and MR simulation incorporating higher-order field terms were devised by expanding MRIReco.jl and KomaMRI.jl. Human brain scans with spiral readouts were also conducted at 7 Tesla. Results: In simulation, using stitching monitored field dynamics resulted in better image reconstruction. Likewise, using our stitching method in in-vivo experiments outperformed the standard field monitoring approach, especially at higher resolution. Impact: Validated with both simulation and real data experiments, our proposed stitching method capable of characterizing challenging imaging gradients using commercially available hardware is believed to have a promise to advance many ultrahigh resolution MRI applications at ultrahigh field.