Interslice current change constrained B₀ shim optimization for accurate high-order dynamic shim updating with strongly reduced eddy currents.

ABSTRACT:

Purpose

To overcome existing challenges in dynamic B₀ shimming by implementing a shim optimization algorithm which limits shim current amplitudes and their temporal variation through the application of constraints and regularization terms.

Theory and methods

Spherical harmonic dynamic B₀ shimming is complicated by eddy currents, ill-posed optimizations, and the need for strong power supplies. Based on the fact that eddy current amplitudes are proportional to the magnitude of the shim current changes, and assuming a smoothness of the B₀ inhomogeneity variation in the slice direction, a novel algorithm was implemented to reduce eddy current generation by limiting interslice shim current changes. Shim degeneracy issues and resulting high current

SUBMITTER: Schwerter M 

PROVIDER: S-EPMC8168441 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature