In-Vivo Human Brain Inhomogeneity Estimation using Susceptibility Registration and Rapid Field Simulation
Rothman D, Koch K, de Graaf R
Rapid in-vivo inhomogeneity simulations have recently been presented which exploit the small susceptibilities (<10-4) of materials compatible with magnetic resonance studies. These simulations present an alternative to time consuming image based field mapping. Such field maps are useful for large-volume shim optimization and post-acquisition geometric distortion correction of echo-planar images. Utilizing field simulations for these purposes requires estimation of the susceptibility distribution within a sample. This can be accomplished by nonlinearly registering a fixed susceptibility model to standard MRI acquisitions. Here, we present the methods of this inhomogeneity estimation procedure and its agreement with experimentally measured field maps.