Research Article

Quantitative Susceptibility Mapping of Magnetic Quadrupole Moments

Figure 8

The effect of the number of orientations on χ, Q1, Q2, and Q3 maps in subject 1. Optimization was performed with 4, 6, 8, and 12 different orientations. As the number of orientation increased, both susceptibility and quadrupole moment maps appeared more similar to those obtained using 12 orientations. The χ, Q1, Q2, and Q3 maps were obtained from the group of directions with the minimum average inner product (, , and for = 8, 6, and 4 orientations, respectively). The average and standard deviation of the relative result difference () over three different groups of orientations (the maximum, mean, and minimum average inner product within that group) were shown below each map.