Rolf F Schulte1, Ralph Noeske2. 1. GE Global Research, Munich, Germany. 2. GE Healthcare, Berlin, Germany.
Abstract
PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Including PNS-limits in the gradient waveform design can shorten the duration of gradient trajectories, thereby reducing associated artifacts.
PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Including PNS-limits in the gradient waveform design can shorten the duration of gradient trajectories, thereby reducing associated artifacts.
Authors: Óscar Peña-Nogales; Yuxin Zhang; Xiaoke Wang; Rodrigo de Luis-Garcia; Santiago Aja-Fernández; James H Holmes; Diego Hernando Journal: Magn Reson Med Date: 2018-11-05 Impact factor: 4.668