[Pattern of cerebral infarct in computerized tomography. Pathophysiologic concepts, validation and clinical relevance]
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1Klinikum RWTH, Aachen.
Insights
This study refines brain infarction classification, distinguishing between hemodynamic low-flow and territorial infarcts using SPECT imaging and vasomotor reactivity tests. Findings aid in diagnosing stroke causes and guiding treatment strategies.
Area of Science:
- Neurology
- Neuroimaging
- Cerebrovascular Disease
Background:
- Hemispheric brain infarctions require accurate classification for effective management.
- Existing classification systems may not fully capture the diverse etiologies of stroke.
- Pathogenetic understanding is crucial for differentiating infarct types.
Purpose of the Study:
- To review and validate a pathogenetically oriented classification system for hemispheric brain infarctions.
- To differentiate between hemodynamic low-flow and territorial infarcts.
- To refine diagnostic and therapeutic strategies for stroke patients based on infarct classification.
Main Methods:
- Retrospective analysis of 73 patients with striato-capsular infarcts.
- Single-photon emission computed tomography (SPECT) imaging to assess cerebral perfusion reserve.
- Measurement of hemispheric vasomotor reactivity (VMR) to capnic stimuli.
- Differentiation of lacunar infarcts from cortical lacunar-like infarcts.
Main Results:
- Two-thirds of large striato-capsular infarcts originated from carotid bifurcation or heart embolism.
- SPECT revealed significantly larger areas of exhausted perfusion reserve in low-flow infarcts compared to territorial infarcts.
- Reduced VMR confirmed hemodynamic compromise in low-flow infarcts, unlike territorial infarcts.
Conclusions:
- The classification system effectively distinguishes infarct types based on pathogenesis.
- SPECT and VMR measurements are valuable tools for identifying hemodynamic low-flow infarcts.
- Accurate classification impacts diagnostic accuracy and therapeutic decisions in stroke care.
Abstract:
Our pathogenetically oriented classification system of hemispheric brain infarctions is reviewed. New data are presented to validate this classification from various points of view. A retrospective analysis of 73 patients with large striato-capsular infarcts demonstrated that two-thirds of them had a source of embolism either in the carotid bifurcation or in the heart. SPECT-imaging in patients with hemispheric brain infarctions of various origin revealed that the area of exhausted cerebral perfusion reserve largely exceeds the area of the infarct visible on CT if a hemodynamically caused low-flow infarction is present. This is not the case in the territorial type. Measurement of the hemispheric vasomotor reactivity to capnic stimuli confirmed this finding by demonstrating a severely reduced VMR in low-flow infarctions, but not in thrombo-embolically caused territorial infarctions. Lacunar infarctions due to occlusion of single long penetrating arteries should be judged as either "unequivocal", "probable" or "possible lacunae" and should be differentiated from small lacunar-like infarctions in the cortex ("non-lacunae") which represent small territorial infarctions due to thromboembolism of small pial arteries. Infarctions in the temporo-parieto-occipital watershed area are difficult to distinguish from territorial infarctions within the posterior part of the middle cerebral artery distribution. For research purposes, such patients should be excluded in order to keep the subgroups homogeneous. Consequences of this classification system for diagnostic and therapeutic strategies in stroke patients are discussed.