Magnetization transfer ratio abnormalities reflect clinically relevant grey matter damage in multiple sclerosis.

Area of Science:

• Neuroimaging
• Neurology
• Biomarkers

Background:

• Grey matter (GM) damage is increasingly recognized as a critical factor in multiple sclerosis (MS) clinical progression, potentially more so than white matter (WM) lesions.
• Understanding the relationship between GM integrity and long-term disability is crucial for MS management.

Purpose of the Study:

• To investigate the association between normal-appearing white matter (NAWM) and GM tissue changes, assessed via magnetization transfer ratio (MTR), and long-term disability in individuals with MS.
• To evaluate MTR-derived histogram parameters in NAWM and GM as potential biomarkers for MS disability.

Main Methods:

• Sixty-nine MS patients (20 years post-clinically isolated syndrome) and 19 healthy controls underwent MRI scans.
• Magnetization transfer ratio (MTR) histograms (mean, peak height, peak location) were analyzed in NAWM and GM.
• Grey matter fraction (GMF) and T2-weighted lesion load were also assessed.

Main Results:

• GM peak height (GM-PH) and, to a lesser extent, NAWM MTR parameters were significantly reduced in MS patients compared to controls.
• GM-PH and GMF showed significant correlations with long-term disability measures, including the Expanded Disability Status Scale (EDSS) and MS functional score.
• GM-PH independently predicted disability, demonstrating its clinical relevance.

Conclusions:

• Grey matter damage, assessed by MTR, is directly related to long-term disability in a cohort of MS patients.
• MTR-based markers of intrinsic GM damage and tissue loss provide clinically relevant information for assessing MS progression and disability.