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Updated: May 1, 2026
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MRI Mapping of Cerebrovascular Reactivity via Gas Inhalation Challenges
Published on: December 17, 2014
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Circadian cerebrovascular reactivity to CO2
J Strohm1, J Duffin2, J A Fisher2
1Department of Medical and Life Sciences, Hochschule Furtwangen University, Germany.
Respiratory Physiology & Neurobiology
|March 25, 2014
Summary
Cerebrovascular reactivity, a measure of brain blood flow regulation, shows a daily rhythm. This repeatable pattern suggests a natural cycle in cerebrovascular health over 24 hours.
Area of Science:
- Neuroscience
- Physiology
- Medical Imaging
Background:
- Cerebrovascular reactivity (CVR) is vital for assessing brain blood flow regulation and cerebrovascular health.
- Trans-cranial Doppler ultrasound measuring middle cerebral artery velocity (MCAv) is a common CVR estimation method.
- CO2 stimulus is frequently used to assess CVR.
Purpose of the Study:
- To investigate the diurnal variation of CVR.
- To assess the repeatability of CVR measurements over two consecutive days.
Main Methods:
- CVR was measured in 10 subjects using trans-cranial Doppler ultrasound.
- MCAv response to a CO2 stimulus was recorded in the morning and evening.
- Mean arterial pressure (MAP) was monitored; CVR was analyzed only when MAP remained stable.
Main Results:
- CVR significantly increased from evening to morning on both study days.
- No significant differences in CVR were observed between the two consecutive days.
- CVR measurements demonstrated significant repeatability.
Conclusions:
- The study concludes that CVR exhibits a circadian rhythm.
- These findings indicate a natural daily fluctuation in cerebrovascular function.
- Repeatable CVR measurements suggest reliability for clinical and research applications.
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