Figure 3 –

Illustration of the ability to determine the ‘stick’ fraction (f_S). The plot shows the NRV (normalized residual variance, Eq. 25) versus the value to which f_S was fixed while fitting the other model parameters, for the protocols in Table 2 under the priors in Table 1. The width of the curve around the ground truth (dashed vertical line) indicates precision by the range of f_S that yield similar goodness-of-fit values. The minima were narrow (high precision) for the CRLB-optimized protocol (I) and the in vivo protocol (II), but wide (poor precision) for the LTE-only protocol (III) and the protocol with multiple TE only for low b-values (IV). However, protocol IV achieved better precision where compartmental difference in isotropic diffusivities were large (C). CRLB-optimized protocols can be susceptible to local minima (B), although the in vivo protocol appeared robust.