Abnormal cerebral microstructures revealed by diffusion kurtosis imaging in amyotrophic lateral sclerosis

Area of Science:

• Neuroimaging
• Neurodegenerative Diseases
• Biomarkers

Background:

• Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by consistent cerebral structural impairment.
• Understanding the microstructural changes in ALS is crucial for developing effective diagnostic and prognostic tools.

Purpose of the Study:

• To investigate cerebral microstructural changes in ALS patients for the first time using diffusion kurtosis imaging (DKI).
• To explore the potential of DKI metrics as biomarkers for assessing disease severity in ALS.

Main Methods:

• A prospective study involving 18 ALS patients and 20 healthy controls.
• Diffusion kurtosis imaging (DKI) was performed using a 3T MRI scanner with specific b-values and diffusion encoding directions.
• Voxel-based analysis was used to compare DKI metrics (MK, AK, RK) and conventional diffusion metrics between groups, alongside correlation analysis with clinical assessments (ALSFRS-R, disease duration).

Main Results:

• ALS patients exhibited significant reductions in mean kurtosis (MK) in both gray and white matter regions, including motor and extramotor areas.
• The spatial distribution of reduced radial kurtosis (RK) mirrored that of decreased MK, while no significant differences in axial kurtosis (AK) were observed.
• Correlation analysis demonstrated significant associations between DKI metrics and clinical measures like ALSFRS-R score and disease duration, with DKI metrics showing a broader spatial extent of changes compared to conventional diffusion metrics.

Conclusions:

• Reduced DKI metrics in ALS indicate a decrease in cerebral microstructural complexity, affecting both motor and non-motor regions.
• DKI metrics show promise as sensitive biomarkers for evaluating disease severity and progression in amyotrophic lateral sclerosis.
• DKI offers a valuable tool for characterizing the microstructural alterations in ALS, potentially improving patient monitoring and therapeutic strategies.