Individual variations of the human corticospinal tract and its hand-related motor fibers using diffusion MRI tractography

Brain Imaging Behav, 2020 · DOI: 10.1007/s11682-018-0006-y · Published: June 1, 2020

Simple Explanation

This paper introduces a new method to map the corticospinal tract (CST) and its hand motor area using MRI. The study uses MRI data from 37 healthy individuals to analyze the CST and hand-related motor fiber tracts (HMFTs). The study creates variability maps to show how the CST and HMFTs differ among individuals, potentially useful for future clinical studies.

Study Duration

Not specified

Participants

37 healthy human subjects

Evidence Level

Level 3, cross-sectional study using diffusion MRI tractography

Key Findings

1
The study successfully delineated the CST and HMFTs using a novel dMRI tractography method.
2
The anatomical variability of the HMFTs was higher compared to the CST.
3
Crossing fibers from other tracts interfere with the accurate delineation of HMFTs.

Research Summary

This study introduces a novel method using dMRI tractography to delineate the CST and isolate its hand motor representation (HMFTs). The study quantifies the variability of these tracts in 37 healthy subjects and creates variability heat maps. The findings reveal significant inter-subject variability, particularly in the HMFTs, and highlight the interference of crossing fibers with accurate delineation.

Practical Implications

Clinical Neurology/Neurorehabilitation Applications

The method can be used to assess nerve axon integrity in neurological conditions with motor system involvement.

Clinical Translation of Novel Therapeutics

The method could be used in clinical studies to assess and quantify the response of neural tissue to new therapeutic interventions.

Reference for Anatomical Studies

The CST variability map created can provide a reference for what is within normal range in the human population.

Study Limitations

1
The dataset used is a HCP high-resolution dataset, meaning that our results may not be reproduced in lower resolution clinical datasets.
2
Delineation methodology is based on the drawing of manual ROIs which may not be feasible for studies with large data cohorts.
3
The tractography is limited to tracing only two-fiber crossings and cannot trace fibers that pass through three-fiber crossings, which may contribute to increased variability of the tracts traced.

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