occlusive diseases fromPET

Objectives-In majorcerebral arterial occlusive diseases, patients withinadequatebloodsupplyrelative tometabolic demand (miseryperfusion) may be at increased riskforcerebral ischaemia. Thisstudyinvestigated whetherpatients showingmiseryperfusion onPET havea highriskofrecurrent ischaemic stroke. Methods-The relationbetweenthe regional haemodynamic status ofcerebral circulation and thesubsequent riskof recurrent stroke wasprospectively evaluatedin 40 patients withsymptomatic internal carotid ormiddlecerebral arterial occlusive diseases who underwentPET. Patients weredivided intotwohaemodynamiccategories according tothemean hemispheric valueofoxygenextraction fraction inthehemisphere supplied by thearterywithsymptomatic disease: patients withnormaloxygenextraction fraction andthosewithincreased oxygen extraction fraction (misery perfusion). All patients werefollowed upforatleast12 months. Results-The oneyearincidence ofipsilateral ischaemic strokes forpatients with normaloxygenextraction fraction and thosewithincreased oxygenextraction fraction weretwoof33andfourofseven patientsrespectively. A significantly higher incidence ofipsilateral strokes was foundinpatients withincreased oxygen extraction fraction (Fisher's exacttest; P = 0-005). In patients withincreased oxygenextraction fraction, threeoffour strokes werewatershed infarctions and the location of the infarction corresponded withtheareaofincreased oxygen extraction fraction. Conclusion-These findings contradict conclusions ofaprevious studyandsuggestthatpatients withmajorcerebral arterial occlusive diseases and misery perfusion havea highriskforrecurrent ischaemic stroke. (CNeurol Neurosurg Psychiatry 1996;61:18-25)