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Transient cell depolarization after permanent middle cerebral artery occlusion: an observation by diffusion-weighted
M L Gyngell1, T Back, M Hoehn-Berlage
1Max-Planck-Institut für neurologische Forschung, Abteilung für experimentelle Neurologie, Köln F. R. Germany.
Abstract:
Focal cerebral ischemia causes rapid intensity changes in diffusion-weighted images (DWI) and elevated lactate as detected by localized proton spectroscopy (1H-MRS). To investigate whether such changes can also be evoked by perischemic depolarizations, we combined DWI and 1H-MRS measurements with DC potential recordings. About 40 min after occlusion of the middle cerebral artery in a rat, a negative DC deflection was observed indicating transient cell depolarization. Coincidentally with the depolarization a transient increase of the DWI signal intensity and a partially reversible increase of lactate occurred in the periphery of the ischemic territory. These results show that peri-ischemic depolarization, known to contribute to the evolution of cerebral infarction, evokes disturbances that can be detected by DWI and 1H-MRS.
Insights
Peri-ischemic depolarization, a key factor in stroke evolution, causes detectable changes in diffusion-weighted imaging (DWI) and proton spectroscopy (1H-MRS). These findings link cellular events to imaging markers in focal cerebral ischemia.
Area of Science:
- Neuroscience
- Medical Imaging
- Biochemistry
Background:
- Focal cerebral ischemia rapidly alters diffusion-weighted images (DWI) and elevates lactate detected by proton spectroscopy (1H-MRS).
- Perischemic depolarizations are implicated in the progression of cerebral infarction.
Purpose of the Study:
- To determine if perischemic depolarizations evoke changes detectable by DWI and 1H-MRS.
- To correlate cellular depolarization events with neuroimaging findings.
Main Methods:
- Combined diffusion-weighted imaging (DWI), localized proton spectroscopy (1H-MRS), and DC potential recordings in a rat model of middle cerebral artery occlusion.
- Monitored changes during and after transient cell depolarization.
Main Results:
- A negative DC potential deflection indicated transient cell depolarization approximately 40 minutes after middle cerebral artery occlusion.
- Coincidentally, a transient increase in DWI signal intensity and a partially reversible lactate increase were observed in the ischemic periphery.
Conclusions:
- Perischemic depolarization events trigger detectable disturbances in DWI signal and lactate levels.
- DWI and 1H-MRS can identify physiological changes associated with peri-ischemic depolarization, contributing to understanding stroke evolution.