Leo K. Tam1, Jason P. Stockmann1, Gigi Galiana2, Dana C. Peters2, Robert Todd Constable, 12
1Biomedical Engineering, Yale University, New Haven, CT, United States; 2Diagnostic Radiology, Yale University, New Haven, CT, United States
Recent nonlinear encoding strategies have provided robust parallel imaging strategies using highly undersampled datasets. Here, we introduce an iterative optimization of the spatial basis in order to achieve efficient encoding and preserve smoothness (reduced dB/dt). To focus the optimization landscape, a library is constructed from the achievable phase profiles from the available gradient strength and phasor combinations. The search prioritizes orthogonality between encoding bases as well as smoothness in transition. Preliminary results with a second order spherical harmonic gradient system suggest significant reductions in dB/dt as compared with parallel echo planar imaging.
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