Optimizing the detection of white matter fMRI using asymmetric spin echo spiral

Area of Science:

• Neuroimaging
• White Matter Physiology

Background:

• Functional magnetic resonance imaging (fMRI) traditionally focuses on gray matter due to higher perfusion.
• Emerging evidence suggests fMRI activation is detectable in white matter.
• Understanding white matter function is crucial for a comprehensive view of brain activity.

Purpose of the Study:

• To investigate the feasibility of detecting white matter fMRI activation.
• To compare the sensitivity of different MRI contrast mechanisms (BOLD vs. T(2)-weighting) for white matter activation.

Main Methods:

• Utilized a 4 Tesla MRI scanner with an asymmetric spin echo spiral (ASE spiral) sequence.
• Acquired data with varying T(2)-weighting to assess contrast sensitivity.
• Employed an interhemispheric transfer task to elicit activation in the corpus callosum.

Main Results:

• White matter fMRI activation was successfully detected in the corpus callosum across all subjects and in group analyses.
• Increased T(2) contrast significantly improved the sensitivity of fMRI signal detection.
• The ASE spiral sequence demonstrated enhanced sensitivity to white matter activation with greater T(2)-weighting.

Conclusions:

• fMRI activation in white matter can be reliably detected.
• T(2)-weighted imaging is more sensitive for detecting white matter fMRI signals compared to standard BOLD contrast.
• These findings support further research into white matter fMRI for a more complete understanding of brain function.