Shaihan J. Malik1,
Joseph V. Hajnal1
1Division
of Imaging Sciences and Biomedical Engineering, Kings College London, London,
United Kingdom
Dynamic RF shimming using a Spatially-Resolved Extended Phase Graph signal model was recently proposed for optimising pseudo-steady-state pulse sequences. The SR-EPG framework is more powerful than simple RF shimming because it considers the effect on the signal from multiple RF pulses. The original method modelled the transient state arising from a single shot, neglecting the effect of incomplete (and spatially variable) recovery that really occurs during multi-shot sequences. This leads to suboptimal results when such sequences are used in practice. In this work the steady-state that arises after multiple shots is modelled and optimized directly, improving the resulting solutions.
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