Progressive gray matter damage in patients with relapsing-remitting multiple sclerosis: a longitudinal diffusion...

Area of Science:

• Neuroimaging
• Biomedical Engineering
• Radiology

Background:

• Diffusion tensor magnetic resonance imaging (DT MRI) offers in vivo insights into tissue microstructure.
• DT MRI has identified subtle structural damage in normal-appearing brain tissues of multiple sclerosis (MS) patients.

Purpose of the Study:

• To assess DT MRI's sensitivity to longitudinal microstructural brain changes in relapsing-remitting MS.
• To detect early signs of damage in normal-appearing brain tissue beyond T2-weighted imaging resolution.

Main Methods:

• Twenty-six untreated relapsing-remitting MS patients underwent 18-month follow-up with serial MRIs.
• DT MRI, T2-weighted, and T1-weighted imaging were used to analyze brain tissue, lesions, and diffusivity.
• Mean diffusivity (D) histograms and fractional anisotropy were calculated for normal-appearing gray matter (GM) and white matter.

Main Results:

• Significant decreases in whole brain tissue volume and GM diffusivity histogram peak height were observed.
• Significant increases in normal-appearing GM diffusivity and T2-hyperintense lesion volumes were noted.
• Changes in GM diffusivity were independent of brain volume changes, indicating distinct pathological processes.

Conclusions:

• DT MRI demonstrates progressive microstructural alterations in the normal-appearing GM of MS patients.
• These findings underscore the significance of GM pathology in MS pathogenesis.
• Gray matter changes detected by DT MRI are not directly linked to concurrent brain atrophy.