Twenty adult human subjects (10 males, mean age ± s.d., age = 40.8 ± 10.3 years; 10 females, age = 39.9 ± 11.3 years) were recruited in accordance with an approved institutional review board protocol for MRI and investigation of PNS thresholds. In addition to PNS tests (described below), each subject was imaged with MAGNUS inserted in an 3.0T MR Scanner (Signa MR750, GE Healthcare, Chicago, IL, USA) with its whole-body gradient and RF coil removed. No PNS tests were performed on the C3T system. A custom 37-cm ID RF transmit/receiver coil was used for transmit with an eight-channel phased-array brain coil receiver. Sagittal 3D T1-weighted inversion recovery-prepared gradient recalled echo (TR/TE/TI=6.4/2.7/450 msec, FOV=28 cm, 2 mm-isotropic, receiver bandwidth=±31.25 kHz) was performed at the first “fixed” position and at each “displaced” position. 3D gradient linearity correction (gradwarp) was performed, utilizing 10th-order spherical harmonics to provide the higher spatial accuracy needed in a head-gradient with smaller linear field-of-view (27 (link)).