In compact-bore MPI systems, the commonly used Opposed-pair Coil suffers from azimuthal dead zones and an insufficient filling factor. We propose a Multi-channel Ring Coil that tiles the bore circumferentially with small, interleaved elements, expanding the sensitive coverage area without increasing volume, thereby improving uniformity and sensitivity. In experiments using a magnetic dipole coil for frequency sweeps, the proposed array—under equal-volume constraints—yields a 58.9\% increase in signal amplitude and a 70.7\% improvement in uniformity over the Opposed-pair baseline. Moreover, each channel in the ring provides multi-angle directional information, offering richer azimuthal inputs for graph-neural-network–based array reception analysis in the future.
Shi et al. (Thu,) studied this question.