Correcting motion-induced B0 shim failure at 3T CMR using a deep-learning-enabled 3D motion-resolved B0 shimming

B0 inhomogeneity is a long-lasting issue for CMR in high-field (3T and above) scanners. B0 shimming is a standard way to improve the B0 field. However, motion-induced field inhomogeneity is an unknown factor in routine practice and compromises cardiac B0 shimming quality. Here, we proposed a motion-resolved cardiac B0 shimming strategy by acquiring motion-resolved cardiac B0 field maps and adopting a modified U-net model for precise and automatic shim field derivation. We showed that dynamic shimming could improve field homogeneity through the respiratory cycle and provide a reliable B0 field for free-breathing CMR at 3T.