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Abstract #0099

Joint Design of Dual-Band Large-Tip-Angle RF and Gradient Waveforms in Parallel Excitation

William A. Grissom1, Adam B. Kerr, Pascal P. Stang2, Greig C. Scott2, Ileana Hancu3, Mika W. Vogel4, John M. Pauly2

1Electrical Engineering and Radiology, Stanford University, Stanford, CA, United States; 2Electrical Engineering, Stanford University, Stanford, CA, United States; 3GE Global Research, Niskayuna, NY, United States; 4Advanced Medical Applications Laboratory, GE Global Research, Munich, Bavaria, Germany

We introduce a new framework for optimizing the phase encoding locations of a 2D or 3D parallel excitation pulse in the large-tip-angle regime. The framework is analogous to the hard pulse approximation, and yields a straightforward analytical relationship between the pulses' spin-domain rotations and the phase encoding locations. This relationship can be exploited to optimize locations using gradient descent, or using optimization transfer for monotonic, parameter-free optimization. We apply our method to the design of dual-band (fat + water) spin echo parallel excitation pulses along 3D rungs trajectories.