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Abstract #0671

Digital Cross-Term Pre-Emphasis for Higher-Order Dynamic Shimming

Signe Johanna Vannesjo1, Benjamin E. Dietrich1, Matteo Pavan1, Christoph Barmet1, 2, Klaas P. Pruessmann1

1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 2Skope Magnetic Resonance Technologies, Zurich, Switzerland

Dynamic shimming holds promise to improve B0 homogeneity for a range of applications, however requires fast updating of the shim fields. Eddy currents limit the shim settling times and also produce strong cross-term field components. Here we show the feasibility of digital cross-term pre-emphasis applied to the input shim waveforms. The pre-emphasis is calculated based on shim impulse response functions (SIRFs) measured with a dynamic field camera. It is shown that settling times can be shortened and cross-term responses much reduced with this approach. The digital pre-emphasis allows for full flexibility in shaping the response, within hardware limitations.