Reconstructing the somatotopic organization of the corticospinal tract remains a challenge for modern tractography methods

TL;DR

This study evaluates six diffusion MRI tractography methods for reconstructing the corticospinal tract's somatotopic organization, highlighting progress and ongoing challenges in accurately mapping this critical brain pathway.

Contribution

The paper systematically compares multiple tractography techniques using HCP data to identify their strengths and limitations in reconstructing the CST's detailed somatotopic organization.

Findings

Progress in reconstructing lateral CST projections

Current methods struggle with comprehensive CST mapping

Challenges remain in accurately capturing medial and lateral projections

Abstract

The corticospinal tract (CST) is a critically important white matter fiber tract in the human brain that enables control of voluntary movements of the body. Diffusion MRI tractography is the only method that enables the study of the anatomy and variability of the CST pathway in human health. In this work, we explored the performance of six widely used tractography methods for reconstructing the CST and its somatotopic organization. We perform experiments using diffusion MRI data from the Human Connectome Project. Four quantitative measurements including reconstruction rate, the WM-GM interface coverage, anatomical distribution of streamlines, and correlation with cortical volumes to assess the advantages and limitations of each method. Overall, we conclude that while current tractography methods have made progress toward the well-known challenge of improving the reconstruction of the lateral projections of the CST, the overall problem of performing a comprehensive CST reconstruction, including clinically important projections in the lateral (hand and face area) and medial portions (leg area), remains an important challenge for diffusion MRI tractography.