In vivo assessment of cervical cord damage in MS patients: a longitudinal diffusion tensor MRI study

Area of Science:

• Neurology
• Radiology
• Biomedical Engineering

Background:

• Cervical cord damage significantly contributes to disability accumulation in multiple sclerosis (MS).
• In vivo quantification of cervical cord damage using Magnetic Resonance Imaging (MRI) is crucial for understanding MS progression.
• Assessing both intrinsic tissue injury and atrophy in the cervical cord is essential.

Purpose of the Study:

• To define the temporal evolution of cervical cord injury and atrophy in MS patients using MRI.
• To investigate the interrelationship between cervical cord tissue injury and atrophy.
• To correlate cervical cord MRI metrics with brain damage and clinical disability.

Main Methods:

• Conventional and diffusion tensor (DT) MRI of the brain and cervical cord were performed on 42 MS patients and 9 controls at baseline and follow-up (mean 2.4 years).
• Measured parameters included cervical cord lesion number, cross-sectional area, mean diffusivity (MD), and fractional anisotropy (FA).
• Brain MRI metrics (lesion volume, grey matter/white matter MD and FA, brain volume changes) and disability scores were also assessed.

Main Results:

• MS patients exhibited decreased cervical cord cross-sectional area and FA, and increased MD over time.
• Cervical cord FA decrease was more pronounced in primary progressive MS compared to other phenotypes.
• No significant correlations were found between cervical cord and brain MRI metrics, or between their changes over time. Baseline cervical cord cross-sectional area and FA correlated with increased disability at follow-up.

Conclusions:

• Progressive tissue loss and injury occur in the cervical cord of MS patients, developing independently and at different rates based on disease phenotype.
• These cervical cord pathologies are not strictly interrelated, necessitating a multiparametric MRI approach for accurate damage assessment.
• Cervical cord damage is associated with medium-term disability accrual in MS, independent of concurrent brain changes.