Jon-Fredrik Nielsen1, Hao Sun2, Jeffrey A Fessler1,2, and Douglas C Noll1
1Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States, 2Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States
We propose a strategy for the joint design of gradient and radiofrequency waveforms for small-tip 3D spatially tailored excitation, that may lead to more globally optimal excitation k-space trajectories. Currently, gradients are either pre-defined or restricted to certain classes such as echo-planar or concentric shells. Our method makes use of a recently proposed optimization method that expresses k-space with a 2nd-order B-spline basis permitting arbitrary k-space trajectories. We employ this method in an Iterated Local Search strategy, and show that this approach reduces the sensitivity of the excited pattern to the choice of initial k-space trajectory that "seeds" the optimization.
