cerebral stroke definitionmiddle cerebral artery ischemic strokemiddle cerebral artery symptomscerebral stroke syndromeleft cerebral artery strokemiddle cerebral artery infarctmiddle cerebral artery thrombosismedial cerebral artery strokemiddle cerebral artery occlusionmiddle cerebral artery syndromecerebral artery infarctioncerebral artery occlusion