We will keep this new page updated with summaries of research findings and methodological advances across ongoing lab studies.
Assessing Cerebral Hemodynamics with BOLD functional MRI
Lag Optimization of Cerebrovascular Reactivity Improves the Relationship with Baseline Cerebral Blood Flow:
Comparing Methods for Mapping Cerebrovascular Reactivity in Breath-Hold fMRI:
End-tidal CO2 is commonly used to map cerebrovascular reactivity (CVR) in fMRI data, but end-tidal CO2 recordings may be unavailable or unreliable in many settings. This study compares two more feasible alternatives — respiration volume per time and average gray matter response — for mapping CVR during a breath-hold task. Our findings suggest that the respiration measurement and average gray matter response can produce similar CVR maps, making them useful alternatives for populations or settings where end-tidal CO2 measurements are difficult to obtain.
Regional Coupling of Macrovascular Flow and Microvascular Cerebrovascular Reactivity in Adolescents:
This study examines the relationship between macrovascular blood flow and microvascular cerebrovascular reactivity (CVR) in adolescents using advanced MRI techniques. We found that higher blood velocity in large arteries is associated with faster CVR response times, while greater blood flow is linked to stronger CVR amplitude in downstream brain regions. Our findings also suggest that these macro- and microvascular dynamics change with age, which could have implications for understanding adolescent brain development and conditions like stroke. This work emphasizes the importance of holistic cerebrovascular assessments and provides valuable normative data for future research in cerebrovascular health.
Improved fMRI Protocol for Characterizing Cerebrovascular Function:
Hemodynamic Delays in Resting-State and Breath-Hold BOLD fMRI:
This study examined the agreement of hemodynamic delay estimates between resting-state and breath-holding conditions using fMRI data in the healthy population. Poor agreement in timing was found across gray matter (GM) voxels, but greater agreement was identified when thresholding to voxels with strong correlations to the GM mean time series, especially near large venous vessels. These results suggest that signal-to-noise factors may affect the accuracy of voxel-wise timing estimates, cautioning against interchangeably using resting-state and breathing-task delay estimates. Further research is needed to understand their sensitivity to vascular physiology and pathology.