Table 5.

Comparisons of magnetic susceptibility measurements between MRI and SQUID. The first column lists the diameters of glass beads. The second column lists calculated susceptibilities (Δχ) from magnetic moments of glass beads obtained at T_E =15 ms in Table 2 and from volumes V_0′ in Table 4. The uncertainties of susceptibility values were calculated through the error propagation method. These are results from MRI. The third column lists the absolute susceptibility value of each bead, by adding −9.05 ppm (which is the absolute susceptibility of water) to each value shown in the second column. We assume no uncertainty of the water susceptibility value. The fourth column lists measured susceptibility of each bead from SQUID. Measurements between our CISSCO method from MRI and SQUID agree within uncertainties. However, different sizes of beads seem to have slightly different susceptibility values.

Beads	MRI	MRI + water	SQUID
2 mm	−2.23 ± 0.32 ppm	−11.3 ± 0.3 ppm	−11.1 ± 0.7 ppm
3 mm	−2.01 ± 0.13 ppm	−11.1 ± 0.1 ppm	−10.8 ± 0.2 ppm
5 mm	−1.82 ± 0.11 ppm	−10.9 ± 0.1 ppm	−10.1 ± 0.7 ppm
6 mm	−1.68 ± 0.09 ppm	−10.7 ± 0.1 ppm	−11.2 ± 0.6 ppm