Fig 2 and Table 2 show the T2 map and values of each phantom. The T2 values decreased with higher MnCl2 concentrations.
Figs 3a-b and 4 and Table 3 show the ADC value of each phantom obtained using RADAR and EPI DWI. In RADAR DWI, no significant differences were observed in the ADC values. In EPI DWI, the ADC values of phantoms with MnCl2 0.40 and 0.80 mM were significantly lower than those of the phantom with an MnCl2 0 mM (1.80 ± 0.09 vs. 2.22 ± 0.02, P < 0.0001; 0.69 ± 0.10 vs. 2.22 ± 0.02 × 10−3mm2s−1, P < 0.0001, respectively). The CVs of RADAR and EPI DWI were 2.27% and 27.37%, respectively.
Fig 5 shows the rADC of each phantom. The rADC of phantoms with MnCl2 0, 0.02, 0.05, 0.10, 0.20, 0.40, and 0.80 mM were 5.68 (4.72–6.32), 8.68 (8.02–9.53), 8.98 (7.92–11.50), 2.98 (1.26–4.69), 8.56 (7.11–10.03), 24.09 (22.60–26.86), and 70.44 % (68.41–74.80), respectively. The rADC of the phantoms with MnCl2 0.40 and 0.80 mM was significantly higher than that of MnCl2 0 mM (P < 0.0001, P < 0.0001, respectively).
Fig 6a and b shows the linear regression analysis. The logarithms of SI and b value correlated linearly for RADAR DWI (R2 = 0.9993 to 0.9999). Meanwhile, a linear correlation between the logarithm of SI and b value was observed in EPI DWI for phantoms with MnCl2 0 mM to 0.20 mM (R2 = 0.9981 to 0.9997), however, a linear correlation collapsed for phantoms with MnCl2 0.40 mM (R2 = 0.9889) and 0.80 mM (R 2=0.8067), respectively.