Figure 3

Phantom imaging. a)$T_2^{\ast }$-weighted magnitude images $\left|{\rho }_{T_{E_m}}^{+}\right|,m=1,\cdots ,4$, b) averaged $T_2^{\ast }$ weighted magnitude image $\left|{\bar{\rho }}^{+}\right|:=\frac{1}{4}\sum _{m=1}^4\left|{\rho }_{T_{E_m}}^{+}\right|$, c) measured $B_z^m$ images at each echo m=1,⋯,4, d) averaged B _z image, $B_z:=\frac{1}{4}\sum _{m=1}^4{B}_z^m$, e)$|\nabla B_z^m|$ images at each echo m=1,⋯,4, f) averaged |∇B _z | image, $|\nabla B_z|:=\frac{1}{4}\sum _{m=1}^4|\nabla B_z^m|$.