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Prediction of malignant course in MCA infarction by PET and microdialysis
Christian Dohmen1, Bert Bosche, Rudolf Graf
1Max Planck Institute for Neurological Research, Department of Neurology, University of Cologne, Cologne, Germany. chris@pet.mpin-koeln.mpg.de
Background And Purpose:
To predict malignant course in patients with large middle cerebral artery (MCA) infarction, we combined PET imaging and neuromonitoring, including microdialysis.
Methods:
Thirty-four patients with stroke of >50% of the MCA territory in early cerebral CT scan were included. Probes for microdialysis and measurement of intracranial pressure and tissue oxygen pressure (Pto2) were placed into the ipsilateral frontal lobe. PET was performed with 11C-flumazenil to assess CBF and irreversible neuronal damage.
Results:
PET measurements within 24 hours after stroke showed larger volumes of ischemic core (mean, 144.5 versus 62.2 cm3) and larger volumes of irreversible neuronal damage (157.9 versus 47.0 cm3) in patients with malignant course (ie, edema formation with midline shift) than in patients with benign course. Mean cerebral blood flow values within the ischemic core were significantly lower and the volume of the ischemic penumbra was smaller in the malignant than in the benign group. In patients with malignant course, cerebral perfusion pressure dropped to <50 to 60 mm Hg 22 to 72 hours (mean, 52.0 hours) after onset of symptoms; subsequently, Pto2 dropped and glutamate increased, indicating secondary ischemia. Maximal changes in the monitored variables reached significant levels for glutamate, aspartate, GABA, glycerol, lactate-to-pyruvate ratio, hypoxanthine, intracranial pressure, cerebral perfusion pressure, and Pto2.
Conclusions:
PET allowed prediction of malignant MCA infarction within the time window suggested for hemicraniectomy. Neuromonitoring helped to classify the clinical courses by characterizing pathophysiological sequelae of malignant edema formation. In contrast to PET, however, it did not predict fatal outcome early enough for successful implementation of invasive therapies.
Insights
Positron emission tomography (PET) can predict malignant middle cerebral artery (MCA) infarction early. Neuromonitoring aids in classifying stroke course but is too late for invasive therapies.
Area of Science:
- Neuroscience
- Radiology
- Critical Care Medicine
Background:
- Large middle cerebral artery (MCA) infarctions can lead to malignant stroke courses.
- Predicting malignant evolution is crucial for timely intervention, such as hemicraniectomy.
Purpose of the Study:
- To evaluate the efficacy of combining PET imaging and neuromonitoring for predicting malignant MCA infarction.
- To assess the predictive value of these methods within the therapeutic window for invasive treatments.
Main Methods:
- Thirty-four patients with >50% MCA territory infarction underwent PET with 11C-flumazenil and neuromonitoring (microdialysis, ICP, Pto2).
- PET assessed cerebral blood flow (CBF) and irreversible neuronal damage.
- Neuromonitoring tracked parameters like intracranial pressure (ICP) and tissue oxygen pressure (Pto2).
Main Results:
- PET identified larger ischemic core and irreversible neuronal damage volumes in patients with malignant MCA infarction.
- Lower CBF and smaller penumbra volumes were observed in the malignant group.
- Neuromonitoring revealed secondary ischemia in malignant cases, with significant changes in glutamate, ICP, and Pto2.
Conclusions:
- PET imaging accurately predicts malignant MCA infarction within the recommended time for hemicraniectomy.
- Neuromonitoring helps characterize stroke progression but is insufficient for early prediction of fatal outcomes.
- Combining PET and neuromonitoring offers valuable insights into stroke pathophysiology and prognosis.