Examining the resting-state vascular connectivity using fMRA in comparison with fMRI: a preliminary study

Area of Science:

• Neuroimaging
• Vascular Neurology
• Radiology

Background:

• Resting-state functional connectivity is crucial for understanding brain function.
• Traditional methods like functional MRI (fMRI) primarily assess blood oxygenation level-dependent (BOLD) signals.
• The vascular system's intrinsic connectivity remains less explored.

Purpose of the Study:

• To investigate resting-state functional connectivity within the brain's vascular system.
• To compare vascular connectivity (using fMRA) with BOLD connectivity (using fMRI).
• To explore the utility of ultra-high-field 7T MRI for detailed vascular imaging.

Main Methods:

• Employed ultra-high-field 7 Tesla (7T) MRI.
• Utilized functional magnetic resonance angiography (fMRA) to assess vascular connectivity.
• Simultaneously performed functional MRI (fMRI) to assess BOLD connectivity.
• Analyzed voxel-wise and region-of-interest (ROI)-wise connectivity maps in four healthy individuals.

Main Results:

• fMRA showed greater correlated voxels in the posterior cingulate cortex compared to fMRI.
• Vascular connectivity exhibited weak interhemispheric correlation in the lateral parietal and temporal cortices.
• Both vascular and BOLD signals showed strong interhemispheric correlations in the precentral gyrus.
• Statistically significant differences (P=0.029) in ROI-wise connectivity between fMRA and fMRI were observed in the lateral parietal and temporal cortices.
• Unlike BOLD, vascular connectivity demonstrated minimal interhemispheric correlation within the default mode network.

Conclusions:

• Ultra-high-field fMRA provides unique insights into arterial-based vascular connectivity.
• fMRA offers supplementary information to fMRI, particularly for cerebrovascular research.
• This technique holds potential for investigating vascular effects in cerebrovascular diseases.