Geometric Fidelity of a Head-Specific 0.5T MR System: An Inter-Scanner Reproducibility Study

Motivation: Reduced susceptibility induced distortions in the mid-field should improve the geometric fidelity of MR acquisitions. Goal(s): The goal of this study was to characterize the geometric fidelity of head-specific 0.5T MR systems. Approach: The geometric fidelity of the system was characterized over six different 0.5T MRI systems using a commercially available distortion phantom. At each site, 3D gradient recalled echo and field map acquisitions were acquired and distortion measurements were computed. Results: The average 95th percentile distortion over the six sites were 0.15±0.03mm and 0.33±0.03mm for 100mm and 180mm diameter spherical volumes respectively. Impact: This study's impact consists of characterizing the geometric fidelity of a head-specific, small-footprint MRI system and assessing its variance across multiple sites.