A: Single-channel B1 inhomogeneity mitigation experiment: RMSE versus number of spokes (T) when providing the sparsity-enforced method Nyquist-sampled, 2×-oversampled, and 3×-oversampled frequency grids of candidate locations. Grid oversampling seems to provide little RMSE benefit. B: Eight-channel system, dual-vein target: RMSE versus T for Nyquist-sampled frequency grids of candidate spoke locations that are 7 × 7,9 × 9,...,19 × 19 in size. Each grid is centered at DC and candidate points extent outward in kx and ky. The 11 × 11 grid yields reasonable RMSE results, suggesting that smaller grids may be used to decrease runtime. A: Effect of oversampling on RMSE. B: Effect of grid extent on RMSE.