Axon Diameter Mapping in Crossing Fibers with Diffusion MRI

Hui Zhang¹, Tim B. Dyrby², Daniel C. Alexander¹

This work presents a technique for axon diameter mapping in fiber crossing regions. Earlier works assume a model of axons with a single dominant orientation. Although valid for many white matter areas, this approach prevents the mapping of regions with crossing fibers that are widespread in the brain and exhibit multiple dominant orientations. A solution to this problem is prerequisite for mapping axon diameter mapping over whole brain. We address this challenge with a crossing-fiber model that enables the simultaneous estimation of crossing configuration and microstructural features. We demonstrate the approach with synthetic and ex vivo brain imaging data.