# Diffusion tractography outside the brain: the road less travelled

## TL;DR

This paper explores how diffusion tractography, a brain imaging technique, is being adapted to study other body tissues, offering new insights into their structure.

## Contribution

The paper surveys and details the methodological adaptations for applying tractography to anatomical structures outside the brain.

## Key findings

- Tractography has been successfully applied to the heart, spinal cord, and peripheral nerves.
- Adaptations are needed to address challenges like physiological motion and lower anisotropy in non-brain tissues.
- The technique provides non-invasive insights into tissue micro-organization for research and clinical use.

## Abstract

Diffusion tractography is a powerful MRI technique for mapping fibrous tissue architecture, traditionally applied to the white matter of the brain. This report surveys the growing application of tractography to anatomical structures outside the brain, a domain that presents both unique challenges and unique opportunities. We examine its use in the heart, spinal cord, peripheral nerves, brachial plexus, kidney, skeletal muscle, and prostate. For each region, we detail the necessary methodological adaptations for acquisition, modeling, and processing, and highlight the unique anatomical information that can be derived for research and clinical applications. While significant challenges remain - spanning technical hurdles like physiological motion and susceptibility artifacts, to biological complexities like lower anisotropy and the interpretation of streamline validity - tractography beyond the brain provides invaluable, non-invasive insights into tissue micro-organization, opening a new frontier for biomedical imaging.