| Literature DB >> 33599026 |
Karl Landheer1, Christoph Juchem1,2.
Abstract
Fast, automatic shimming by mapping along projections (FASTMAP) is an elegant analytical method developed to quantify three-dimensional first- and second-order spherical harmonic B0 shapes along six one-dimensional column projections. The straightforward application of this theoretical concept to B0 shimming, however, neglects crucial aspects of sequence implementation and shim hardware, commonly necessitating multistep iterative adjustments. We demonstrate a software package, referred to as FASTMAP Shim Tool (FAMASITO), which is composed of a FASTMAP pulse sequence, automated calibration and analysis routines, and a script for automatically performing experiments. With FAMASITO we demonstrate optimal single-step adjustment of first- and second-order terms (with potential <1% mean refinement of linear terms) in the prefrontal cortex of seven volunteers, one of the most difficult-to-shim areas in the adult human brain.Entities:
Keywords: FASTMAP; active shimming; spherical harmonic functions
Mesh:
Year: 2021 PMID: 33599026 DOI: 10.1002/nbm.4486
Source DB: PubMed Journal: NMR Biomed ISSN: 0952-3480 Impact factor: 4.044