Multiple sclerosis: low-frequency temporal blood oxygen level-dependent fluctuations indicate reduced functional...

Area of Science:

• Neuroimaging
• Neurology
• Medical Physics

Background:

• Multiple sclerosis (MS) is a demyelinating disease affecting the central nervous system.
• Altered functional connectivity is increasingly recognized as a hallmark of MS pathology.
• Understanding motor network alterations is crucial for MS diagnosis and management.

Purpose of the Study:

• To investigate the correlation of low-frequency blood oxygenation level-dependent (BOLD) fluctuations between the primary motor cortices of the left and right hemispheres.
• To compare functional connectivity in motor regions between healthy controls and patients with MS.
• To assess the diagnostic potential of BOLD fluctuation correlations in MS.

Main Methods:

• Magnetic resonance (MR) imaging was performed on 16 healthy volunteers and 20 MS patients using a 1.5-T imager.
• Low-frequency BOLD fluctuations (<0.08 Hz) were recorded at rest and during a bilateral finger-tapping task.
• Cross-correlations of BOLD signals were calculated, focusing on the precentral gyrus, to quantify interhemispheric functional connectivity.

Main Results:

• A distinct difference in functional connectivity was observed between MS patients and controls.
• Patients with MS exhibited a significantly lower fraction of correlated pixels in the right precentral gyrus compared to controls.
• The method demonstrated high diagnostic performance with >60% sensitivity and 100% specificity for MS detection.

Conclusions:

• Patients with MS demonstrate reduced functional connectivity between the primary motor cortices of the right and left hemispheres.
• Low-frequency BOLD fluctuation analysis provides a sensitive and specific measure for differentiating MS patients from healthy individuals.
• Clinical MS disease severity did not correlate with the observed changes in interhemispheric motor cortex connectivity.