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Cerebrovascular reactivity changes in acute concussion: a controlled cohort study
Runrun Wang1,2,3, Julien Poublanc1, Adrian P Crawley1
1Joint Department of Medical Imaging, University Health Network, The Toronto Western Hospital, The University of Toronto, Toronto, Ontario, Canada.
Quantitative Imaging in Medicine and Surgery
|November 5, 2021
Summary
Acute concussion disrupts cerebrovascular reactivity (CVR) speed, particularly in white matter, despite normal global CVR. This BOLD MRI method offers a reliable way to assess concussion severity and duration.
Area of Science:
- Neuroimaging
- Neurology
- Cardiovascular Physiology
Background:
- Concussion can disrupt normal cerebrovascular reactivity (CVR), affecting cerebral blood flow regulation.
- Previous evidence indicates CVR increases in the first week post-concussion, suggesting impaired autoregulation.
- This study investigates the speed of CVR response and regional impairments in acute concussion.
Purpose of the Study:
- To investigate the effects of acute concussion on the speed of cerebrovascular reactivity (CVR) response.
- To visualize global and regional impairments in CVR in individual patients with acute concussion.
- To assess the clinical utility of BOLD MRI with precise CO2 control for evaluating concussion.
Main Methods:
- Prospective study including 12 patients with concussion (less than 1 week) and 12 age/sex-matched healthy controls.
- Cerebrovascular reactivity (CVR) assessed using BOLD MRI with controlled end-tidal partial pressure of CO2 (PETCO2) challenges.
- Calculated CVR amplitude and response time (tau) in gray and white matter, converted to z-scores using atlases from 39 healthy controls.
Main Results:
- White matter showed significantly higher CVR magnitude and shorter response time (tau) in concussed patients compared to controls.
- Gray matter showed a trend towards shorter tau in concussed patients, but CVR magnitude was not significantly different.
- Z-score analysis revealed significantly lower z tau values in both gray and white matter for concussed patients; z step was the most sensitive parameter.
Conclusions:
- Concussion is associated with patient-specific BOLD cerebrovascular responsiveness abnormalities, even with normal global CVR.
- BOLD MRI with precise CO2 control is a safe, reliable, and clinically useful method for evaluating concussion.
- This technique has potential for assessing concussion severity and symptom duration.
