Clinical And Neuroimaginal Features In Patients With Middle Cerebral Artery Stenosis And Occlusion

Background:The atherosclerotic stenosis of the intracranial arteries is the most important cause of acute ischemic stroke among Chinese patients,especially of the middle cerebral artery(MCA).The previous studies were focused on total occlusion of the MCA by an embolus originating from the carotid artery or the cardiac chambers which occurs frequently in acute stroke patients.But the patterns and mechanisms of stroke in patients with atherosclerotic MCA disease remain unclear.Purpose:We sought to identify the clinical and neuroimaginal features and the stroke mechanisms associated with unilateral MCA stenosis or occlusion using early diffusion-weighted imaging(DWI) and magnetic resonance angiography(MRA).Methods:We reviewed 30 patients admitted to the department of Neurology in Qilu hospital between May 1,2008 and January 31,2009.Patients were included in this study if they hadâ‘ ischemic lesions located in the unilateral MCA territory or the watershed areas;â‘¡corresponding MCA stenosis or occlusion.Acute DWI lesion patterns were classified as perforating artery infarct(PAI),pial infarct(PI) and water-shed infarct(WSI) according to the distribution of acute infarcts on DWI.we also categorized the infarcts as single or multiple on the basis of the number of them.Results:Among the 30 patients with MCA stenosis or occlusion,5 had transient ischemic attack(TIA),2 were asymptomatic and 23 had acute stroke.DWI showed that 5 patients(3 with TIA and 2 asymptomatic) had no acute cerebral infarcts,7 had single acute cerebral infarcts and 18(2 with TIA and 16 with acute stroke) had multiple acute cerebral infarcts.No complete MCA territory infarct was found.Both lesion patterns of the 2 patients with TIA are lacunars.Among the 16 patients with acute stroke and multiple lesions,Water-shed infarct were the most common pattern(10 patients),and for 7 patients with single infarcts,penetrating artery infarcts were the most common(6 patients).No single pial infarcts were found.Conclusions:1.Multiple acute cerebral infarcts are found most frequently in atherosclerotic stenosis or occlusion of MCA,among which water-shed infarcts accompanying pial and(or) penetrating infarcts are the most common patterns.The stroke mechanism of them was an artery-to-artery embolism with impaired clearance of emboli resulting from hypoperfusion.2.The isolated lacuna-like penetrating infarcts can be caused by local branch occlusion.Clinicians should exclude large artery disease while making diagnosis of lacuna infarction.3.The construction of the collateral circulation is closely associated with the size of the infarcts and the severity of clinical signs.4.There are variable lesions patterns in patients with MCA stenosis or occlusion, and the corresponding stroke mechanism are different either.Individual therapeutic strategies should be taken for each pattern.