Signe Johanna Vannesjo1, Christian Vogt1, Lars Kasper1,2, Maximilian Haeberlin1, and Klaas P Pruessmann1
1Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland, 2Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
Accurate gradient time-courses are crucial for MRI, yet actual
waveforms generally deviate from ideal. We here propose to treat the task of
finding the ideal gradient input for a targeted output gradient waveform as a
case-by-case optimization problem, based on an LTI model of the gradient
system. The method is aimed to achieve optimal gradient waveform fidelity that
a given gradient system is capable of producing, considering both bandwidth and
amplitude/slew rate limitations. We perform the optimization for an EPI and a
spiral sequence and compare the resulting output to using non-optimized input
on measured k-space trajectories.
