Figure 10.
The impact of deviations from the optimal solution on the relative contrast-to-noise ratio (CNR) of each component (coloured lines) and on the sum of squared coefficients of variation (SSCV) measure (black line). Each plot shows the effect of changing the b-value of the corresponding shell away from the value identified as optimal (denoted by the dashed vertical line). The CNR for each component is shown as a fraction of its value at the overall optimum to allow all plots to coexist on the same scale. This suggests that the optimum is fairly broad, and performance is likely to be relatively tolerant of deviations in the b-values, particularly for the highest shell. In general, the acquisition is more sensitive to the largest component (component 1) with lower b-values, at the expense of sensitivity to the weakest components. This was produced assuming a scheme consisting of four b-value shells to estimate four components, and T 2 = 150 ms