Untangling the R2* contrast in multiple sclerosis: A combined MRI-histology study at 7.0 Tesla

Area of Science:

• Neuroimaging
• Neuroscience
• Biomarker Discovery

Background:

• Multiple sclerosis (MS) involves pathological changes in brain iron and myelin content.
• T2*-weighted imaging and its reciprocal R2* are sensitive to iron, offering potential insights into MS.
• Understanding the interplay of iron and myelin is crucial for elucidating MS pathogenesis.

Purpose of the Study:

• To investigate the relationship between R2*, myelin, and iron content in the brains of deceased multiple sclerosis patients.
• To explore the potential of R2* as a biomarker for tissue integrity in MS.
• To differentiate the regional effects of myelin and iron on R2* variations.

Main Methods:

• Coronal slices from 8 MS patient brains were imaged using 7.0 Tesla MRI (3D T2*-weighted multi-echo gradient-echo and 2D T2-weighted turbo spin echo sequences).
• Histopathological analyses quantified myelin (Luxol fast blue, proteolipid staining) and iron (Turnbull blue staining).
• R2*, myelin, and iron intensity were quantified and correlated.

Main Results:

• Regional variations in R2* were observed in MS brains.
• The influence of myelin and iron content on R2* varied across different brain regions.
• A complex interplay between R2*, myelin, and iron was identified.

Conclusions:

• R2* variations are differentially affected by myelin and iron content in specific regions of MS brains.
• R2* shows promise as a potential in vivo biomarker for assessing tissue integrity in multiple sclerosis.
• Further investigation is warranted to validate R2* as a clinical biomarker for MS progression and treatment response.