[Pattern of cerebral infarct in computerized tomography. Pathophysiologic concepts, validation and clinical...

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.