The effect of gradient sampling schemes on diffusion metrics derived from probabilistic analysis and tract-based spatial statistics

Low FA values decreased significantly with increasing Nd and with increasing NSA. MD was only marginally sensitive to Nd and NSA. NV2 increased significantly with Nd but not with NSA. Thus, we conclude that accurate estimation of standard diffusion metrics FA and MD is mainly dependent on the signal-to-noise ratio (SNR), whereas the ability to differentiate multiple fiber populations requires a high diffusion sampling density.