William A. Grissom1, Adam B. Kerr1,
Pascal P. Stang1, Michael Lustig2, Greig C. Scott1,
John M. Pauly1
1Electrical Engineering, Stanford
University, Stanford, CA, United States; 2Electrical Engineering,
University of California, Berkeley, Berkeley, CA, United States
Multidimensional
and parallel excitation pulses are highly sensitive to trajectory
imperfections resulting from eddy currents and gradient amplifier
nonlinearity. It has been recently proposed to solve this by redesigning RF
pulses on measured trajectories; however, this approach is not compatible
with RF pulse design methods in which the RF and gradients are designed
jointly. We introduce an iterative technique for gradient preemphasis for
multidimensional and parallel excitation. The method is capable of overcoming
gradient amplifier non-linearities, and obviates the need to redesign pulses
on a measured trajectory.