Impact of through-slice gradient regularization for dynamic slice-wise B0 shimming in the brain and spinal cord

Motivation: Excessive B0 inhomogeneities in the brain (especially in the frontal lobe) and the spinal cord complicate imaging, leading to issues such as signal loss and distortions —effects that become more pronounced at higher field strengths. Goal(s): Implement dynamic slice-wise updating and study the effect of signal recovery optimization in the spine (3T) and brain (7T). Approach: Implement dynamic slice-wise shimming with AC/DC coils, incorporating a regularization term into the optimization to account for through-slice gradients. Results: Significant signal recovery was achieved in the brain and spine, with a maximum tSNR improvement of 200% in the upper thoracic cord, without compromising geometric distortions. Impact: Dynamic shimming with AC/DC coils, optimized through signal recovery regularization, enhances the precision and quality of gradient-echo imaging, enabling more reliable functional MRI studies in regions prone to high susceptibility distortions.