Quantitative Susceptibility Mapping of Magnetic Quadrupole Moments

Figure 2

Numerical simulation of the quadrupole contribution to the magnetic field. The field profile of the gray line in the Input χ (top left) is plotted as blue (dipole + quadrupole), red (dipole), and black line (ground truth) in the field graphs (right). Increasing the downsampling factor, effectively equivalent to increasing voxel size, the dipole + quadrupole field (blue) remains closer to the ground truth (black). This is especially notable for downsampling factors 4 and 6, where the dipole + quadrupole field (blue) captures the field peak at the boundary of the input sphere, whereas the dipole field (red) shows a noticeable drop.