Impaired cerebrovascular reactivity in multiple sclerosis

Area of Science:

• Neuroimaging
• Vascular Biology
• Neurology

Background:

• Cerebrovascular reactivity (CVR) is crucial for maintaining brain blood flow.
• Neurovascular coupling integrity is vital for brain health.
• CVR abnormalities have not been previously studied in multiple sclerosis (MS).

Purpose of the Study:

• To assess CVR impairment in MS patients using hypercapnic perfusion MRI.
• To investigate the relationship between CVR, lesion load, and brain atrophy in MS.

Main Methods:

• 19 MS patients and 19 controls underwent perfusion MRI.
• Cerebral blood flow (CBF) was measured under normocapnia and hypercapnia (5% CO2).
• CVR was calculated as the percentage increase in CBF during hypercapnia.

Main Results:

• MS patients exhibited significantly reduced global gray matter CVR compared to controls.
• Voxel-by-voxel analysis revealed diffuse CVR reductions in multiple brain regions in MS.
• CVR reduction correlated negatively with lesion volume and positively with gray matter atrophy.

Conclusions:

• Quantitative MRI demonstrates impaired cerebrovascular function in MS.
• A diffuse decrease in CVR suggests a potential underlying mechanism for neurodegeneration in MS.
• These findings highlight the importance of cerebrovascular health in MS pathophysiology.