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Updated: Mar 17, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Multiparametric magnetic resonance imaging including oxygenation mapping of experimental ischaemic stroke
Ligia Simões Braga Boisserand1,2,3, Benjamin Lemasson1,2, Lydiane Hirschler1,2,4
11 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.
Abstract:
Recent advances in MRI methodology, such as microvascular and brain oxygenation (StO2) imaging, may prove useful in obtaining information about the severity of the acute stroke. We assessed the potential of StO2 to detect the ischaemic core in the acute phase compared to apparent diffusion coefficient and to predict the final necrosis. Sprague-Dawley rats (n = 38) were imaged during acute stroke (D0) and 21 days after (D21). A multiparametric MRI protocol was performed at 4.7T to characterize brain damage within three region of interest: 'LesionD0' (diffusion), 'Mismatch' representing penumbra (perfusion/diffusion) and 'Hypoxia' (voxels < 40% of StO2 within the region of interest LesionD0). Voxel-based analysis of stroke revealed heterogeneity of the region of interest LesionD0, which included voxels with different degrees of oxygenation decrease. This finding was supported by a dramatic decrease of vascular and perfusion parameters within the region of interest hypoxia. This zone presented the lowest values of almost all parameters analysed, indicating a higher severity. Our study demonstrates the potential of StO2 magnetic resonance imaging to more accurately detect the ischaemic core without the inclusion of any reversible ischaemic damage. Our follow-up study indicates that apparent diffusion coefficient imaging overestimated the final necrosis while StO2 imaging did not.
Insights
Brain oxygenation (StO2) imaging accurately detects the ischemic core in acute stroke, unlike diffusion imaging. StO2 MRI shows greater precision in identifying stroke severity and predicting final tissue damage.
Area of Science:
- Neuroimaging
- Stroke research
- Magnetic Resonance Imaging (MRI)
Background:
- Acute stroke diagnosis relies on accurate identification of the ischemic core and penumbra.
- Current MRI techniques like apparent diffusion coefficient (ADC) imaging may overestimate final infarct size.
- Brain oxygenation (StO2) imaging offers a potential new method for assessing stroke severity.
Purpose of the Study:
- To evaluate the efficacy of StO2 MRI in detecting the ischemic core during acute stroke.
- To compare StO2 imaging with ADC imaging for predicting final necrosis.
- To assess the potential of StO2 to differentiate irreversible ischemic damage from reversible areas.
Main Methods:
- A multiparametric MRI protocol was applied to Sprague-Dawley rats at 4.7T during acute stroke (D0) and 21 days post-stroke (D21).
- Regions of interest included 'LesionD0' (diffusion), 'Mismatch' (penumbra), and 'Hypoxia' (StO2 < 40%).
- Voxel-based analysis characterized brain damage and oxygenation levels.
Main Results:
- Voxel-based analysis revealed heterogeneity in the ischemic core, with varying degrees of oxygenation decrease.
- The 'Hypoxia' region exhibited significantly decreased vascular and perfusion parameters, indicating higher severity.
- StO2 imaging accurately identified the ischemic core without including reversible damage, unlike ADC imaging which overestimated necrosis.
Conclusions:
- StO2 magnetic resonance imaging is a promising tool for accurately detecting the ischemic core in acute stroke.
- StO2 imaging provides a more precise assessment of stroke severity and final tissue damage compared to ADC imaging.
- This technique holds potential for improved clinical management of acute stroke patients.
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