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Diffusion- and perfusion-weighted MR imaging of transient focal cerebral ischaemia in mice
F A van Dorsten1, R Hata, K Maeda
1Max-Planck-Institute for Neurological Research, Department of Experimental Neurology, Cologne, Germany.
Abstract:
Temporary focal ischaemia was induced in wild-type C57Black/6 mice by thread occlusion of the middle cerebral artery (MCA). Recirculation was started after 60 min and maintained for 24 h, after which the mouse brain was frozen in situ. Development of the cerebral infarct was monitored by diffusion-, perfusion- and T(2)-weighted magnetic resonance imaging (MRI) during ischaemia, during the early reperfusion period of 90 min, and at 24 h after reperfusion. Ischaemia caused a marked reduction of the perfusion signal intensity and of the apparent diffusion coefficient (ADC) of tissue water in the ipsilateral MCA territory. In sham-operated control animals ADC remained unchanged. Hemispheric lesion volume after 1 h MCA occlusion was 53 +/- 6% (n = 6), as defined by an ADC decrease of more than 20%. Recirculation reduced hemispheric lesion volume to only 27 +/- 13%, while there was a trend towards secondary lesion growth at 24 h. Post-ischaemic recovery of perfusion was slow, heterogeneous and incomplete. A region-of-interest analysis showed only partial and transient recovery of the ADC, particularly in the dorsolateral cortex and lateral caudate putamen, which may be explained by inadequate reperfusion in these regions. Detailed MRI studies of cerebral ischaemia and reperfusion may now also be performed in the transgenic mice.
Insights
Temporary middle cerebral artery occlusion in mice caused significant brain damage. Recirculation partially reduced lesion volume but showed incomplete perfusion recovery, indicating potential for secondary lesion growth.
Area of Science:
- Neuroscience
- Medical Imaging
- Cerebrovascular Research
Background:
- Focal cerebral ischemia is a major cause of stroke.
- Understanding reperfusion's impact on infarct development is crucial.
- Magnetic Resonance Imaging (MRI) offers detailed insights into ischemic brain injury.
Purpose of the Study:
- To investigate the effects of temporary middle cerebral artery occlusion and subsequent reperfusion on cerebral infarct development in mice.
- To characterize the temporal evolution of ischemic lesions using advanced MRI techniques.
- To assess the recovery of tissue perfusion and diffusion after reperfusion.
Main Methods:
- Induction of temporary focal cerebral ischemia via middle cerebral artery (MCA) occlusion in C57Black/6 mice.
- Monitoring of cerebral infarct development using diffusion-, perfusion-, and T2-weighted MRI at various time points.
- Quantitative analysis of apparent diffusion coefficient (ADC) and lesion volume changes.
Main Results:
- MCA occlusion led to a significant decrease in perfusion and ADC in the ipsilateral MCA territory.
- Hemispheric lesion volume was reduced by reperfusion, but incomplete and heterogeneous perfusion recovery was observed.
- Partial and transient ADC recovery occurred, particularly in the dorsolateral cortex and lateral caudate putamen, suggesting inadequate reperfusion.
Conclusions:
- Temporary focal cerebral ischemia causes significant brain damage, with reperfusion offering partial but incomplete protection.
- Inadequate reperfusion in specific brain regions may limit recovery and contribute to secondary lesion growth.
- Advanced MRI techniques are valuable for detailed studies of cerebral ischemia and reperfusion, applicable to transgenic mouse models.