Figure 6.

This plot presents the average error in ADC (standard deviation in a 3^rd degree polynomial fit to the mean ADC of an ROI over the course of a scan) after correction for each of the five methods for 10 consecutive sessions using the ice water phantom with varying numbers of interspersed minimally weighted (“b0”) volumes (labeled in the x-axis). The appended letter of the x-axis label indicates the phase encoding direction (L = rll R= rlr). The three rows correspond to the three ROI’s in Figure 1, as indicated. The left column presents a comparison of the five methods. In the low variance ROI (first row), overall errors are small and little difference is observed between methods. In the two ROIs of higher variance, T_x, and TS outperform T for all scans. Note that in some scans, the uncorrected method out performs the T corrected scans. The right column studies simulated rate of b0 volumes by dropping out the b0s from the first two scans. Observe that with at least 4 b0s, the model errors are stable and low, which is intuitive as a second degree model is fit for #b0s>3 and a first degree model is fit for #b0<=3.