Whole Brain Spherical Mean Value Filtering for Shadow Reduction in Quantitative Susceptibility Mapping

Morphology Enabled Dipole Inversion (MEDI) is an iterative reconstruction algorithm for Quantitative Susceptibility Mapping (QSM) that is effective in suppressing streaking artifacts by exploiting the magnitude image as a morphological prior. However, contiguous areas of dipole incompatibility (such as noise) induce shadow artifacts whose spatial frequency components are not sufficiently regularized by the gradient-based regularization in MEDI. The harmonic quality allows the use of the maximum corollary of Green’s theorem to remove residual background field. This mSMV approach reduces shadows and preserves brain volume, comparing favorably to existing algorithms.