Longitudinal gray matter changes in multiple sclerosis--differential scanner and overall disease-related effects

Area of Science:

• Neuroimaging
• Neurology
• Medical Imaging Analysis

Background:

• Voxel-based morphometry (VBM) is crucial for studying gray matter (GM) atrophy in multiple sclerosis (MS).
• Multi-center studies face challenges with cross-scanner variations potentially hindering VBM's effectiveness in detecting disease-specific changes.
• Longitudinal VBM analysis requires understanding inter-site comparability.

Purpose of the Study:

• To evaluate longitudinal inter-site differences and comparability of regional GM in MS patients using VBM.
• To assess the impact of different MRI scanners on detecting GM volume changes over time.
• To determine if data from multiple centers can be pooled for combined analysis.

Main Methods:

• Longitudinal 3D T1-weighted MRI data from 248 relapsing-remitting MS patients across two centers were analyzed.
• Voxel-based morphometry (VBM) was used to assess regional gray matter (GM) volume changes between baseline and year 2.
• Analyses controlled for age, gender, disease duration, and global GM volume, comparing effects between two different 1.5T MR scanners.

Main Results:

• The main effect of time on regional GM volume was larger in center two compared to center one.
• Differential GM volume reductions were observed in fronto-temporal and limbic cortical regions.
• Overall disease-related effects were significant in the cerebellum, uncus, and several cortical/lobular regions, with differential effects being smaller.

Conclusions:

• Scanner-induced effects on longitudinal GM volume differences in MS patients are relatively small.
• The comparability of regional GM changes across different scanners is sufficient.
• Pooling MRI data from multiple centers for combined VBM analysis in MS research is feasible and recommended.