Stroke penumbra defined by an MRI-based oxygen challenge technique: 2. Validation based on the consequences of reperfusion

Robertson, C. A., McCabe, C. , Gallagher, L., Lopez Gonzalez, M. d., Holmes, W. M. , Condon, B., Muir, K. W. , Santosh, C. and Macrae, I. M. (2011) Stroke penumbra defined by an MRI-based oxygen challenge technique: 2. Validation based on the consequences of reperfusion. Journal of Cerebral Blood Flow and Metabolism, 31(8), pp. 1788-1798. (doi: 10.1038/jcbfm.2011.67)

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Magnetic resonance imaging (MRI) with oxygen challenge (T2* OC) uses oxygen as a metabolic biotracer to define penumbral tissue based on CMRO2 and oxygen extraction fraction. Penumbra displays a greater T2* signal change during OC than surrounding tissue. Since timely restoration of cerebral blood flow (CBF) should salvage penumbra, T2* OC was tested by examining the consequences of reperfusion on T2* OC-defined penumbra. Transient ischemia (109±20 minutes) was induced in male Sprague-Dawley rats (n=8). Penumbra was identified on T2*-weighted MRI during OC. Ischemia and ischemic injury were identified on CBF and apparent diffusion coefficient maps, respectively. Reperfusion was induced and scans repeated. T2 for final infarct and T2* OC were run on day 7. T2* signal increase to OC was 3.4% in contralateral cortex and caudate nucleus and was unaffected by reperfusion. In OC-defined penumbra, T2* signal increased by 8.4%±4.1% during ischemia and returned to 3.25%±0.8% following reperfusion. Ischemic core T2* signal increase was 0.39%±0.47% during ischemia and 0.84%±1.8% on reperfusion. Penumbral CBF increased from 41.94±13 to 116.5±25 mL per 100 g per minute on reperfusion. On day 7, OC-defined penumbra gave a normal OC response and was located outside the infarct. T2* OC-defined penumbra recovered when CBF was restored, providing further validation of the utility of T2* OC for acute stroke management.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Gallagher, Mrs Lindsay and Macrae, Professor Mhairi and Condon, Professor Barrie and Santosh, Dr Celestine and Holmes, Dr William and Muir, Professor Keith and Lopez Gonzalez, Dr Maria Del and McCabe, Dr Chris
Authors: Robertson, C. A., McCabe, C., Gallagher, L., Lopez Gonzalez, M. d., Holmes, W. M., Condon, B., Muir, K. W., Santosh, C., and Macrae, I. M.
Subjects:R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
College/School:College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
Journal Name:Journal of Cerebral Blood Flow and Metabolism
Publisher:Nature Publishing Group
ISSN (Online):1559-7016
Published Online:11 May 2011
Copyright Holders:Copyright © 2011 International Society for Cerebral Blood Flow and Metabolism
First Published:First published in Journal of Cerebral Blood Flow and Metabolism 2011
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
455001Imaging the ischaemic penumbra using BOLD MRI with oxygen challenge as a biotracerI MacraeMedical Research Council (MRC)G0700439Institute of Neuroscience and Psychology