Abstract Details

Title Cerebrovascular Reactivity: Subject-Level Classification Model for Acute Concussion.

Topic Neuro Trauma, Critical Care, and Sports Neurology

Presentation(s) P11 - Poster Session 11 (8:00 AM-9:00 AM)

Poster/Presentation
Number 5-007

Objective To assess both group- and subject-level changes in CVR metrics (speed and magnitude of response) to a standardized vasodilatory stimulus during the acute stage of recovery post concussion.

Background Concussion research has focused on examining neuronal disruptions post injury with little exploration on how injury may alter neurovascular coupling. Emerging evidence indicates that blood flow metrics could be more sensitive for detecting concussion than measures of neuronal integrity. Cerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow per unit change in vasodilatory stimulus. CVR has been used to examine the integrity of autoregulation and neurovascular coupling. Our recent work has shown that CVR metrics including speed and magnitude of flow change to a standardized vasodilatory stimulus is constant across the adult age range. Deviations from this response could potentially be used for assessing individual subjects following concussion, especially given that blood flow dysregulation is known to occur following concussion.

Design/Methods 19 concussed and 19 healthy controls (HC) underwent CVR assessment using Blood oxygen dependent MRI during precise changes in arterial Co₂(RespirAct^TM). The speed and magnitude of response to the CO2 stimulus were calculated in grey and white matter.

Results CVR metrics (speed and magnitude of response) were higher and faster in concussed participants relative to HC, with white matter showing greater responses than grey matter. A leave-one-out ROC analysis was able to classify between concussed and HC subjects (AUC of 00945, p < 0.000) with a reasonable degree of accuracy. The optimal cut-off resulted in a sensitivity of 0.947 and a specificity of 0.158 for this analysis.

Conclusions Our results are surprising in that we have never seen supernormal response to a vasodilatory stimuli in any other cerebrovascular disease. CVR metrics hold promise for detecting acute concussion at the subject level compared to neuronal injury metrics alone.

Authors/Disclosures
PRESENTER	No disclosure on file
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David J. Mikulis, MD (Toronto Hosp Western Div)	Dr. Mikulis has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Neinstein Personal Injury Lawyers. Dr. Mikulis has received stock or an ownership interest from Thornhill Medical, Inc.. Dr. Mikulis has received intellectual property interests from a discovery or technology relating to health care.

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