Minimal number of sampling directions for robust measures of the spherical mean diffusion weighted signal: Effects of sampling directions, b-value, signal-to-noise ratio, hardware, and fitting strategy

Summary

Simulations and brain and spinal cord measurements establish how many diffusion directions are needed to estimate the spherical mean signal reliably. A lookup table links sampling requirements to diffusion weighting, signal-to-noise ratio, and fitting choices.

Study overview

Spherical-mean diffusion models can support efficient microstructural imaging, but their accuracy depends on directional sampling. This work varies the number of directions, b-value, noise level, hardware, and fitting strategy in simulations, then checks those predictions with brain and spinal cord data. The resulting guidance helps balance acquisition time against measurement precision.

Main findings

• Directional sampling requirements depend on b-value, noise, and fitting strategy.
• Empirical brain and spinal cord measurements agreed with the simulations.