CATERPillar : a fast and flexible framework framework for generating synthetic white matter numerical phantoms

Motivation: Building realistic and complex white matter numerical phantoms is needed for accurate diffusion MRI simulations but challenging to achieve. Goal(s): The creation of white matter (WM) numerical phantoms by mimicking realisitic parallel axonal growth. Approach: This tool uses overlapping spheres to build realistic axons and parallels their growth to decrease the running time while reliably preventing collisions. Results: High intracellular volume fraction values can be reached (up to 70%) for tortuous, variable-caliber axons. The parallelism of the growth decreases the run-time. Impact: Creating numerical phantoms that accurately represent white matter can improve the accuracy of results in diffusion MRI studies using Monte Carlo simulations.