Simultaneous multislice refocusing by time-optimal control

We demonstrate the design of minimum duration SMS refocusing pulses and slice selective gradient shapes with specific hardware constraints such as peak B1, peak slew rate and peak amplitude of the slice gradient. The proposed bi-level time-optimal control method works with a detailed description of the slice profile accuracy by inequality constraints, and allows the use of fine spatial and temporal grids. The optimized results are validated on a 3T scanner with phantom and in vivo measurements demonstrating the practical realizability of the presented approach.