Short-Range Structural Connections Are More Severely Damaged in Early-Stage MS

Area of Science:

• Neuroimaging
• Neurology
• Biomedical Engineering

Background:

• Long-range connections are crucial for cognition in advanced multiple sclerosis (MS).
• The progression of network damage in early MS remains poorly understood.
• Investigating early-stage MS damage patterns is vital for understanding disease evolution.

Purpose of the Study:

• To determine if short- and long-range structural connections experience equal damage in early-stage MS.
• To compare the microstructural integrity of white matter (WM) fibers in early MS.
• To assess the impact of MS on brain network connectivity.

Main Methods:

• Utilized high-resolution, multishell diffusion MRI on 7T scanners for 16 early MS patients and 17 controls.
• Analyzed macrostructural properties of short- and long-range fibers.
• Applied Diffusion Tensor Imaging (DTI) and Neurite Orientation Dispersion and Density Imaging (NODDI) for microstructural analysis.

Main Results:

• Early MS patients exhibited significant WM integrity damage, including higher radial diffusivity and lower intracellular volume fraction.
• Microstructure changes were observed in both short- and long-range fibers, with increased radial, mean, and axial diffusivity.
• Z-score analysis revealed greater damage in short-range fibers compared to long-range fibers.

Conclusions:

• Early-stage MS involves more severe demyelination and axonal degeneration in short-range connections than long-range ones.
• Findings suggest potential cortical lesions undetectable by current MRI techniques.
• Understanding differential damage patterns is key for early MS diagnosis and treatment.