Changes in functional connectivity in relapsing-remitting multiple sclerosis spinal cord measured via region-based
Atlee A Witt1,2, Anna J E Combes1,3, Anirban Sengupta1,4
1Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States.
Abstract:
The clinical picture of persons with multiple sclerosis (pwMS), a neuroinflammatory disease characterized by demyelination, does not consistently correlate with pathology noted on clinical magnetic resonance imaging (MRI). Functional MRI (fMRI) is a valuable tool to understand neural network alterations resulting from structural damage, with studies in the brain employing both region-of-interest and data-driven assessment of functional connectivity. However, similar studies in the spinal cord (SC) remain limited given the challenge of imaging a small structure in an area with substantial physiologic noise. We sought to apply resting-state fMRI at 3T in the SC of healthy controls (HC) and persons with relapsing-remitting MS (pwRRMS) to assess differences in functional connectivity and relate functional markers to clinicial measures of disability. Consistent with prior SC studies, we determined strongest functional connectivity between ventral gray matter horns in both HCs and pwMS and diminished mobility associated with reduced functional connectivity. Using independent-component analysis, we observed a possible compensatory mechanism of increased connectivity in earlier compared with later stages of relapsing-remitting MS. Further exploration is warranted, and our findings support the notion of functional alterations in the SC of pwMS.
Insights
Functional MRI reveals altered spinal cord connectivity in multiple sclerosis (MS) patients, potentially indicating a compensatory mechanism in earlier disease stages. This research highlights functional changes in the MS spinal cord.
Area of Science:
- Neuroscience
- Radiology
- Neurology
Background:
- Multiple sclerosis (MS) is a neuroinflammatory disease where clinical symptoms do not always correlate with MRI-detected pathology.
- Functional magnetic resonance imaging (fMRI) is crucial for understanding neural network changes due to structural damage.
- Spinal cord (SC) fMRI studies are limited by the SC's small size and physiological noise.
Purpose of the Study:
- To investigate functional connectivity differences in the spinal cord of persons with relapsing-remitting MS (pwRRMS) compared to healthy controls (HC).
- To explore the relationship between spinal cord functional connectivity and clinical disability measures in pwMS.
- To assess potential compensatory mechanisms in the spinal cord during different stages of MS.
Main Methods:
- Resting-state fMRI at 3 Tesla was employed in the spinal cord of HC and pwRRMS.
- Functional connectivity was assessed using independent component analysis.
- Clinical disability measures were correlated with functional connectivity findings.
Main Results:
- Strongest functional connectivity was observed between ventral gray matter horns in both HC and pwMS.
- Reduced functional connectivity was associated with diminished mobility in pwMS.
- A potential compensatory mechanism of increased connectivity was noted in earlier stages of pwRRMS compared to later stages.
Conclusions:
- Functional alterations exist in the spinal cord of persons with multiple sclerosis.
- Spinal cord functional connectivity changes may reflect disease progression and compensatory strategies.
- Further research is warranted to fully understand the role of spinal cord functional connectivity in MS.
