# DTI changes of brachial plexus nerve roots in amyotrophic lateral sclerosis and their correlation with electrophysiology

## TL;DR

This study explores how diffusion tensor imaging (DTI) can detect changes in the brachial plexus of amyotrophic lateral sclerosis (ALS) patients and how these changes relate to nerve function.

## Contribution

The study introduces DTI as a novel method to assess microstructural changes in ALS brachial plexus and correlate them with electrophysiological and clinical markers.

## Key findings

- ALS patients showed significantly lower FA and AD and higher RD in brachial plexus compared to controls.
- FA and AD positively correlated with clinical and electrophysiological measures, while RD showed negative correlations.
- DTI parameters may serve as potential biomarkers for upper limb neurodegeneration in ALS.

## Abstract

Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disease with peripheral nerve involvement, but current diagnostics are limited. Diffusion tensor imaging (DTI) may improve microstructural assessment and correlate with clinical markers. We investigated the diffusion properties of the brachial plexus in ALS and examined their relationships with electrophysiological parameters of upper limb nerves.

We enrolled 25 ALS patients and 22 age- and sex-matched healthy controls. DTI of the brachial plexus was conducted to measure fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Differences in DTI parameters between the two groups were analyzed. Correlations between DTI parameters and ALS Functional Rating Scale-Revised (ALSFRS-R) scores, along with electrophysiological measurements, were assessed.

In ALS patients compared to controls, FA and AD values were significantly lower (p ≤ 0.002), while the RD value was significantly higher (p = 0.002). There were no statistically significant differences in MD (p = 0.540). Both FA and AD showed a positive correlation with ALSFRS-R score, ALSFRS-upper limb score, and compound muscle action potential amplitude of median, ulnar, and radial nerves (r ≥ 0.480; p ≤ 0.015). The RD values showed a negative correlation with ALSFRS-upper limb score and motor nerve conduction velocity of median, ulnar, and radial nerves (r ≤ -0.415; p ≤ 0.039).

FA, AD, and RD values of DTI showed the potential to identify microstructural changes in the brachial plexus nerve roots of ALS patients and may serve as potential indicators of nerve conduction function in the upper extremities.

DTI may reveal microstructural changes in ALS brachial plexus, correlating with nerve dysfunction, offering novel biomarkers for evaluation of upper limb neurodegeneration.

Lower Fractional anisotropy (FA) and axial diffusivity (AD), and higher radial diffusivity (RD) were shown in amyotrophic lateral sclerosis (ALS) brachial plexus.Diffusion tensor imaging (DTI) parameters correlated with clinical and electrophysiological parameters.FA, AD, and RD detected ALS nerve microstructural changes, indicating abnormal conduction function.

Lower Fractional anisotropy (FA) and axial diffusivity (AD), and higher radial diffusivity (RD) were shown in amyotrophic lateral sclerosis (ALS) brachial plexus.

Diffusion tensor imaging (DTI) parameters correlated with clinical and electrophysiological parameters.

FA, AD, and RD detected ALS nerve microstructural changes, indicating abnormal conduction function.