Peripheral nerve stimulation-optimal gradient waveform design.

Abstract

Modern magnetic resonance imaging scanners with high-performance gradient systems have high maximum gradient strength (Gmax ) and slew rate (Smax ). Peripheral nerve stimulation (PNS) is often a more limiting factor for gradient waveform design than Gmax and Smax . Traditionally, the slew rate is derated globally to adhere to PNS limitations. In this work, the PNS limitation is already included in the gradient waveform design in the form of a time-varying slew rate, hence shortening the overall gradient duration. Spiral and echo-planar imaging trajectories were designed with a multitude of parameters, and it was demonstrated that trajectory durations from conventional to PNS-optimal design can be shortened by 8 and 3%, respectively. Including PNS-limits in the gradient waveform design can shorten the duration of gradient trajectories, thereby reducing associated artifacts.