Category: RespirAct

A Conceptual Model for CO2-induced Redistribution of Cerebral Blood Flow with Experimental Confirmation using BOLD MRI

O Sobczyk, A Battisti-Charbonney, J Fierstra, D M Mandell, J Poublanc, A P Crawley, D J Mikulis, J Duffin, J A Fisher. Neuroimage. 2014 May 15;92:56-68. doi: 10.1016/j.neuroimage.2014.01.051. Epub 2014 Feb 5.
Cerebrovascular reactivity (CVR) is the change in cerebral blood flow (CBF) in response to a change in a vasoactive stimulus. Paradoxical reductions in CBF in response to vasodilatory stimulation (‘steal’) are associated with vascular pathology. However, a pathophysiological interpretation of ‘steal’ requires a comprehensive conceptual model linking pathology and changes in blood flow. Herein, we extend a simple model explaining steal published in the late 1960s by incorporating concepts of CBF regulation from more recent studies to generate a comprehensive dynamic model.

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The Dynamics of Cerebrovascular Reactivity Shown with Transfer Function Analysis

J Duffin, O Sobczyk, A P Crawley, J Poublanc, D J Mikulis, J A Fisher. Neuroimage. 2015 Jul 1;114:207-16. doi: 10.1016/j.neuroimage.2015.04.029. Epub 2015 Apr 16.
Cerebrovascular reactivity (CVR) is often defined as the increase in cerebral blood flow (CBF) produced by an increase in carbon dioxide (CO2) and may be used clinically to assess the health of the cerebrovasculature. When CBF is estimated using blood oxygen level dependent (BOLD) magnetic resonance imaging, CVR values for each voxel can be displayed using a color scale mapped onto the corresponding anatomical scan.

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Identifying Significant Changes in Cerebrovascular Reactivity to Carbon Dioxide

O Sobczyk, A P Crawley, J Poublanc, K Sam, D M Mandell, D J Mikulis, J Duffin, J A Fisher. AJNR Am J Neuroradiol. 2016 May;37(5):818-24.
doi: 10.3174/ajnr.A4679. Epub 2016 Feb 4.
Background and purpose: Changes in cerebrovascular reactivity can be used to assess disease progression and response to therapy but require discrimination of pathology from normal test-to-test variability. Such variability is due to variations in methodology, technology, and physiology with time. With uniform test conditions, our aim was to determine the test-to-test variability of cerebrovascular reactivity in healthy subjects and in patients with known cerebrovascular disease.

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