Fiber-Flux Diffusion Density for White Matter Tracts Analysis: Application to Mild Anomalies Localization in Contact Sports Players

TL;DR

This paper introduces Fiber-Flux Diffusion Density (FFDD), a novel method combining diffusivity and fiber flux measures to analyze white matter tracts, improving detection of subtle anomalies in contact sports players.

Contribution

The paper presents FFDD vectors and a dissimilarity measure for precise along-tract analysis, enhancing sensitivity over standard FA methods for identifying white matter anomalies.

Findings

FFDD reveals significant anomalies in contact sports players' white matter.

The method outperforms standard FA analysis in sensitivity.

Aligned tract profiles enable meaningful inter-subject comparisons.

Abstract

We present the concept of fiber-flux density for locally quantifying white matter (WM) fiber bundles. By combining scalar diffusivity measures (e.g., fractional anisotropy) with fiber-flux measurements, we define new local descriptors called Fiber-Flux Diffusion Density (FFDD) vectors. Applying each descriptor throughout fiber bundles allows along-tract coupling of a specific diffusion measure with geometrical properties, such as fiber orientation and coherence. A key step in the proposed framework is the construction of an FFDD dissimilarity measure for sub-voxel alignment of fiber bundles, based on the fast marching method (FMM). The obtained aligned WM tract-profiles enable meaningful inter-subject comparisons and group-wise statistical analysis. We demonstrate our method using two different datasets of contact sports players. Along-tract pairwise comparison as well as group-wise analysis, with respect to non-player healthy controls, reveal significant and spatially-consistent FFDD anomalies. Comparing our method with along-tract FA analysis shows improved sensitivity to subtle structural anomalies in football players over standard FA measurements.