Diffusion tensor imaging detects corticospinal tract involvement at multiple levels in amyotrophic lateral sclerosis

Area of Science:

• Neuroimaging
• Neurology
• Biomedical Engineering

Background:

• Histopathological studies of amyotrophic lateral sclerosis (ALS) examine end-stage disease.
• Diffusion tensor imaging (DTI) offers in vivo investigation of corticospinal tract pathology in ALS.

Purpose of the Study:

• To investigate corticospinal tract pathology in ALS using DTI.
• To compare water diffusion characteristics in the corticospinal tracts between ALS patients and healthy controls.

Main Methods:

• DTI was employed to assess water diffusion in the corticospinal tracts of 21 ALS patients and 14 controls.
• Fractional anisotropy (FA) and mean diffusivity (MD) were measured along the pyramidal tracts.
• Mixed model regression analysis compared FA and MD between groups.

Main Results:

• Fractional anisotropy (FA) was lower in ALS patients compared to controls across multiple corticospinal tract levels.
• Mean diffusivity (MD) was elevated at the internal capsule level in ALS patients but not consistently lower down the tract.
• No correlation was observed between clinical disability markers and DTI-derived water diffusion indices.

Conclusions:

• DTI reveals distinct diffusion characteristics in the corticospinal tracts of ALS patients, providing insights into disease pathology.
• Variations in diffusion at different anatomical levels may reflect tract architecture or pathological distribution.
• DTI holds potential for monitoring ALS progression and treatment efficacy.