Figure 1From: Paramagnetic artifact and safety criteria for human brain mappingParamagnetic effects of gradient magnetic fields on the pulmonary circulation during human brain mapping. (A) Magnetic field strength (Bz), and calculated field gradient (-dBz/dz) and force product (-Bz·dBz/dz) along the centerline of the magnet (see 'Supplementary Method 2' in Additional file 1). Maximal values of -dBz/dz at Bz = 1.5, 3.0, 4.0, 7.0 and 10 T were 1.03, 2.06, 2.75, 4.81 and 6.87 T/m, respectively (at z = 1.47 m). Maximal values of -Bz·dBz/dz at Bz = 1.5, 3.0, 4.0, 7.0 and 10 T were 1.21, 4.84, 8.60, 26.40 and 53.75 T2/m, respectively (at z = 1.14 m), which are well covered by the range of our experiment shown in Fig. 1B. The head and lung of a healthy volunteer, whose height is 1.75 m, head length is 0.25 m, length of epigastric fossa from top of head is 0.5 m, were positioned at the magnet's center (A: z = 0 m) and at maximal of -Bz·dBz/dz (B: z = 1.14 m), respectively. (B) Maximally estimated redistribution of erythrocytes estimated in the pulmonary circulation at position B (see 'Supplementary Method 3' in Additional file).Back to article page