Abstract: A method for assessing and/or reducing artifacts arising from reconstruction of magnetic particle imaging (MPI) total image data set (c(r)) from MPI signal data (s(f), u(t)) using an appended system matrix (SM_AB) comprises: a) reconstructing signal data (s(f), u(t)) using appended system matrix (SM_AB) derived from at least two system matrices (SM_A, SM_B) for generating input image data (cin(r)); b) selecting at least one voxel as selected voxel from the input image data (cin(r)) for generating output image data (cout(r)); c) determining eigen-reconstruction signal data sen(f) by selecting one or more line entries of the appended system matrix (SM_AB) that correspond to the selected voxel(s); d) reconstructing eigen-reconstruction signal data se(f) using the appended system matrix (SM_AB) for generating eigen-reconstruction image data ce(r); and e) subtracting the eigen-reconstruction image data ce(r) or weighted eigen-reconstruction image data ce?(r) from the input image data cin(r) for generating updat