Stephen James Wastling1, David John Lythgoe1,
Gareth John Barker1
1Centre for Neuroimaging
Sciences,
Previous workers have shown the feasibility of recovering signal in regions of GE-EPI images with susceptibility-induced signal dropout by combining two images acquired using different z-shim gradients. We have demonstrated that by constraining the algorithm used to select the two z-shims to grey matter voxels on a slice-by-slice basis improves signal recovery over their whole-brain optimisation scheme.