Figure 4:

A) The distribution of MD deviation from the ground truth in an ROI of randomly distributed voxels over the entire brain when denoising is applied prior to fitting and when no denoising is applied, compared to the distribution of MD in an ROI of the PLIC. This example illustrates that a correct signal model/representation works as well as denoising (i.e., in the perfect model case denoising should not yield extra benefit if the fitting is unbiased and no imaging artifacts are introduced). B) Variability of Diffusivity scales linearly with noise variance (PLIC of HCP phantom). The residual variance extrapolated to zero noise level provides an estimate for the inherent biological variability.