PNS Analysis on Folded and Non-folded Gradient Coil Designs with a Coupled EM-Neurodynamic Simulation Method

The gradient coil (GC) is an essential component in MRI scanners as it provides linear Bz fields for spatial encoding. In advanced neuroimaging applications, head-only GCs have significant advantages over whole-body GCs. This is because the smaller GC can achieve higher gradient amplitude (Gmax) and higher slew rate (SR) more efficiently and usually also has a higher peripheral nerve stimulation (PNS) threshold. With the advent of high levels of Gmax and SR to significantly improve the quality and geometric fidelity of structural and functional brain imaging, methodologies for PNS prediction and assessment become more critical for patient safety. In this work, we first designed one non-folded and one folded X-coil with the target field method [1] , then we utilized a coupled EM-neurodynamic simulation method to compare the PNS response of these two coils and further proposed a design with lower PNS risk by balancing electric field intensities in different part of the body.