Heterogeneous patterns of vasoreactivity in the middle cerebral and internal carotid arteries

This study compared changes in cross-sectional area (CSA) and flow (Q) between the middle cerebral artery (MCA) and the internal carotid artery (ICA) at baseline and during 5 min of hypercapnia (HC; 6% CO2) and hypocapnia (HO; hyperventilation) and quantified how these changes contribute to estimate...

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Bibliographic Details
Published in:American journal of physiology. Heart and circulatory physiology 2015-05, Vol.308 (9), p.H1030-H1038
Main Authors: Coverdale, Nicole S, Lalande, Sophie, Perrotta, Amanda, Shoemaker, J Kevin
Format: Article
Language:English
Subjects:
Adaptation, Physiological
Adult
Blood Flow Velocity
Brain
Carotid Artery, Internal - diagnostic imaging
Carotid Artery, Internal - physiopathology
Cerebrovascular Circulation
Female
Flow velocity
Humans
Hypercapnia - diagnostic imaging
Hypercapnia - physiopathology
Hypocapnia - diagnostic imaging
Hypocapnia - physiopathology
Magnetic Resonance Imaging
Male
Middle Cerebral Artery - diagnostic imaging
Middle Cerebral Artery - physiopathology
NMR
Nuclear magnetic resonance
Physiology
Regional Blood Flow
Time Factors
Ultrasonic imaging
Ultrasonography, Doppler, Duplex
Ultrasonography, Doppler, Pulsed
Ultrasonography, Doppler, Transcranial
Vasoconstriction
Vasodilation
Veins & arteries
Young Adult
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Summary:This study compared changes in cross-sectional area (CSA) and flow (Q) between the middle cerebral artery (MCA) and the internal carotid artery (ICA) at baseline and during 5 min of hypercapnia (HC; 6% CO2) and hypocapnia (HO; hyperventilation) and quantified how these changes contribute to estimates of cerebrovascular reactivity (CVR). Measures of MCA CSA were made using 3T magnetic resonance imaging. On a separate day, MCA flow velocity was measured with transcranial Doppler ultrasound and ICA diameters and flow velocity were measured with duplex ultrasound. Fourteen subjects (23 ± 3 yr, 7 females) participated, providing data for 11 subjects during HC and 9 subjects during HO. An increase in MCA CSA (P < 0.05) was observed within the first minute of HC. During HO, the decrease in MCA CSA (P < 0.05) was delayed until minute 4. No changes were observed in ICA CSA during HC or HO. The relative changes in QICA and QMCA were similar during HC and HO. Therefore, the MCA, but not ICA, dilates and constricts during 5 min of HC and HO, respectively. The consequent impact on QMCA significantly affects estimates of CVR, and reactivity cannot be attributed solely to changes in smaller arterioles.
ISSN:0363-6135
1522-1539
DOI:10.1152/ajpheart.00761.2014