Longitudinal diffusion tensor imaging in amyotrophic lateral sclerosis.

Area of Science:

• Neuroimaging
• Neurodegenerative Diseases
• White Matter Imaging

Background:

• Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive motor neuron loss.
• Subcortical white matter alterations are a prominent feature in ALS pathology.
• Diffusion tensor imaging (DTI) is a non-invasive technique to assess white matter integrity by measuring proton diffusion (ADC) and directionality (FA).

Purpose of the Study:

• To investigate white matter microstructural changes in ALS patients using DTI.
• To assess the potential of DTI as a biomarker for tracking disease progression in ALS.
• To correlate DTI findings with clinical measures of disease severity and functional status.

Main Methods:

• 24 ALS patients and 24 age-matched controls underwent 1.5T DTI scans.
• Statistical parametric mapping (SPM) was used to analyze fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values.
• Follow-up DTI scans were acquired in 15 ALS patients after 6 months to monitor disease progression.

Main Results:

• Reduced FA was observed in the corticospinal tract (CST) and frontal white matter, consistent with existing findings.
• Follow-up DTI demonstrated progressive FA decrease along the CST and in frontal areas, reflecting upper motor neuron degeneration.
• Decreased FA in the cerebellum (culmen, declive) was detected, supporting cerebellar involvement in ALS pathology.
• Structural changes correlated significantly with disease duration, ALSFRS-R scores, and physical and executive function deficits.

Conclusions:

• DTI effectively detects characteristic white matter changes in ALS, highlighting its potential as a sensitive biomarker.
• Longitudinal DTI analysis can capture the progression of neurodegeneration in ALS.
• DTI findings correlate with clinical progression, underscoring its utility in monitoring disease trajectory and therapeutic response.