Influence of 100% and 40% oxygen on penumbral blood flow, oxygen level, and T2*-weighted MRI in a rat stroke model (original) (raw)

Baskerville, Tracey, Deuchar, Graeme A., McCabe, Chris ORCID: https://orcid.org/0000-0003-3111-031X, Robertson, Craig A., Holmes, William M. ORCID: https://orcid.org/0000-0002-0942-215X, Santosh, Celestine and Macrae, I. Mhairi(2011) Influence of 100% and 40% oxygen on penumbral blood flow, oxygen level, and T2*-weighted MRI in a rat stroke model.Journal of Cerebral Blood Flow and Metabolism, 31(8), pp. 1799-1806. (doi: 10.1038/jcbfm.2011.65)

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Publisher's URL: http://dx.doi.org/10.1038/jcbfm.2011.65

Abstract

Accurate imaging of the ischemic penumbra is a prerequisite for acute clinical stroke research. T2* magnetic resonance imaging (MRI) combined with an oxygen challenge (OC) is being developed to detect penumbra based on changes in blood deoxyhemoglobin. However, inducing OC with 100% O2 induces sinus artefacts on human scans and influences cerebral blood flow (CBF), which can affect T2* signal. Therefore, we investigated replacing 100% O2 OC with 40% O2 OC (5 minutes 40% O2 versus 100% O2) and determined the effects on blood pressure (BP), CBF, tissue pO2, and T2* signal change in presumed penumbra in a rat stroke model. Probes implanted into penumbra and contralateral cortex simultaneously recorded pO2 and CBF during 40% O2 (n=6) or 100% O2 (n=8) OC. In a separate MRI study, T2* signal change to 40% O2 (n=6) and 100% O2 (n=5) OC was compared. Oxygen challenge (40% and 100% O2) increased BP by 8.2% and 18.1%, penumbra CBF by 5% and 15%, and penumbra pO2 levels by 80% and 144%, respectively. T2* signal significantly increased by 4.56%±1.61% and 8.65%±3.66% in penumbra compared with 2.98%±1.56% and 2.79%±0.66% in contralateral cortex and 1.09%±0.82% and −0.32%±0.67% in ischemic core, respectively. For diagnostic imaging, 40% O2 OC could provide sufficient T2* signal change to detect penumbra with limited influence in BP and CBF.

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Funder and Project Information

1

Imaging the ischaemic penumbra using BOLD MRI with oxygen challenge as a biotracer

I Macrae

G0700439

Institute of Neuroscience and Psychology

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