Potential use of oxygen as a metabolic biosensor in combination with T2*-weighted MRI to define the ischemic penumbra

Santosh, C. et al. (2008) Potential use of oxygen as a metabolic biosensor in combination with T2*-weighted MRI to define the ischemic penumbra. Journal of Cerebral Blood Flow and Metabolism, 28(10), pp. 1742-1753. (doi:10.1038/jcbfm.2008.56)

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Publisher's URL: http://dx.doi.org/10.1038/jcbfm.2008.56

Abstract

We describe a novel magnetic resonance imaging technique for detecting metabolism indirectly through changes in oxyhemoglobin:deoxyhemoglobin ratios and T2* signal change during ‘oxygen challenge’ (OC, 5 mins 100% O2). During OC, T2* increase reflects O2 binding to deoxyhemoglobin, which is formed when metabolizing tissues take up oxygen. Here OC has been applied to identify tissue metabolism within the ischemic brain. Permanent middle cerebral artery occlusion was induced in rats. In series 1 scanning (n=5), diffusion-weighted imaging (DWI) was performed, followed by echo-planar T2* acquired during OC and perfusion-weighted imaging (PWI, arterial spin labeling). Oxygen challenge induced a T2* signal increase of 1.8%, 3.7%, and 0.24% in the contralateral cortex, ipsilateral cortex within the PWI/DWI mismatch zone, and ischemic core, respectively. T2* and apparent diffusion coefficient (ADC) map coregistration revealed that the T2* signal increase extended into the ADC lesion (3.4%). In series 2 (n=5), FLASH T2* and ADC maps coregistered with histology revealed a T2* signal increase of 4.9% in the histologically defined border zone (55% normal neuronal morphology, located within the ADC lesion boundary) compared with a 0.7% increase in the cortical ischemic core (92% neuronal ischemic cell change, core ADC lesion). Oxygen challenge has potential clinical utility and, by distinguishing metabolically active and inactive tissues within hypoperfused regions, could provide a more precise assessment of penumbra.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Gallagher, Mrs Lindsay and Condon, Professor Barrie and Holmes, Dr William and Macrae, Professor I Mhairi and Muir, Professor Keith and Graham, Professor David Ian and McCabe, Dr Chris and Brennan, Dr David and Hadley, Professor Donald and Santosh, Dr Celestine
Authors: Santosh, C., Brennan, D., McCabe, C., Macrae, I. M., Holmes, W. M., Graham, D. I., Gallagher, L., Condon, B., Hadley, D. M., Muir, K. W., and Gsell, W.
Subjects:R Medicine > R Medicine (General)
College/School:College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Journal Name:Journal of Cerebral Blood Flow and Metabolism
Publisher:Nature Publishing Group
ISSN:0271-678X
ISSN (Online):1559-7016
Published Online:11 June 2008
Copyright Holders:Copyright © 2008 International Society for Cerebral Blood Flow and Metabolism
First Published:First published in Journal of Cerebral Blood Flow and Metabolism 28(10):1742-1753
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