A novel approach with "skeletonised MTR" measures tract-specific microstructural changes in early primary-progressive...

Area of Science:

• Neuroimaging
• Neurology
• Radiology

Background:

• Primary-progressive multiple sclerosis (PPMS) is characterized by gradual neurological decline.
• Understanding early white matter (WM) changes is crucial for tracking disease progression and developing interventions.

Purpose of the Study:

• To investigate tract-specific short-term changes in WM microstructure in early PPMS using combined diffusion tensor imaging (DTI) and magnetization transfer (MT) imaging.
• To correlate these imaging changes with clinical disability progression.

Main Methods:

• Twenty-one early PPMS patients underwent DTI and MT imaging at baseline and 12 months.
• Tract-based spatial statistics (TBSS) was used to analyze fractional anisotropy (FA), diffusivities, and MT ratio (MTR) changes.
• Clinical disability assessments were performed concurrently.

Main Results:

• Significant MTR decreases were observed in the corpus callosum, corticospinal tracts, and longitudinal fasciculi, within both lesions and normal-appearing WM.
• No significant changes in FA were detected, but radial diffusivity increased in several WM tracts.
• Decreases in MTR and increases in radial diffusivity in the corpus callosum and corticospinal tracts correlated with upper limb functional decline.

Conclusions:

• Multimodal MRI reveals tract-specific microstructural WM damage in early PPMS.
• These changes contribute to clinical impairment and offer potential biomarkers for disease progression.
• The proposed imaging methodology can be adapted for studying other neurological diseases.