Research Article

Quantitative Susceptibility Mapping of Magnetic Quadrupole Moments

Table 1

Sharpness measurement at the structural boundaries. Average norm of the susceptibility gradient in the boundary regions (ppm/mm). The value is calculated as in , where is a voxel index and is the total number of voxels in the boundary region (Supporting Figure S1). The higher the value, the sharper the edge. DS: down-sampling factor.

Numerical brain phantom PhantomHuman

DS 2
Truth: 1.32×10−2
DS 4
Truth: 7.33×10−3
Balloon1
(3.26 ppm)
Balloon2
(1.63 ppm)
Balloon3
(0.82ppm)
Balloon4
(0.41 ppm)
Subject 1Subject 2

D+Q1.32×10−26.51×10−31.360.660.320.151.60×10−21.58×10−2

D6.78×10−33.60×10−31.310.630.320.161.13×10−21.19×10−2