Brain white matter abnormalities and correlation with severity in amyotrophic lateral sclerosis: An atlas-based...

Area of Science:

• Neuroimaging
• Neurology
• Biomedical Engineering

Background:

• Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting motor neurons.
• White matter (WM) microstructural integrity is crucial for neurological function.
• Diffusion tensor imaging (DTI) is a powerful MRI technique for assessing WM microstructure.

Purpose of the Study:

• To investigate white matter (WM) microstructural alterations in amyotrophic lateral sclerosis (ALS) patients using diffusion tensor imaging (DTI).
• To correlate DTI-derived metrics with clinical factors in ALS.
• To evaluate the diagnostic potential of DTI metrics for ALS.

Main Methods:

• DTI data acquired from 18 ALS patients and 16 healthy controls.
• Atlas-based region of interest (ROI) analysis using intra-voxel (FA, MD) and inter-voxel (LDH) diffusion metrics.
• Correlation analysis with clinical scores (ALSFRS-R, disease duration) and Receiver Operating Characteristic (ROC) analysis.

Main Results:

• Significant reductions in fractional anisotropy (FA) observed in bilateral corticospinal tract (CST) and right uncinate fasciculus (RUF) in ALS patients.
• Increased mean diffusivity (MD) detected in right CST, left cingulum hippocampus (LCH), RUF, and right superior longitudinal fasciculus (RSLF).
• Decreased local diffusion homogeneity (LDH) found in bilateral anterior thalamic radiation (ATR), bilateral CST, and left inferior frontal-occipital fasciculus (LIFOF).
• FA in bilateral CST correlated with ALSFRS-R scores and progression rate; LDH in right CST correlated with disease duration.
• ROC analysis demonstrated the feasibility of using CST diffusion metrics to differentiate ALS patients from controls (AUC = 0.792–0.868).

Conclusions:

• WM microstructural alterations are a common feature in ALS, detectable by both intra- and inter-voxel DTI metrics.
• Inter-voxel diffusion measurements, such as LDH, may offer superior assessment of abnormalities in WM tracts like ATR and LIFOF.
• DTI metrics, particularly along the CST, show potential for distinguishing ALS patients and correlating with disease progression.