| Background and purpose: Hypoperfusion and embolization as thepathogenesises of acute ischemic stroke are widely accepted. But therelationship of them is unclear. We prospectively studied consecutive acuteischemic stroke patients with middle cerebral artery stenosis detected bytranscranial Doppler and magnetic resonance angiography in order to analyzethe potentral mechanism of MCA and relationship between hypoperfusion andembolization.Method: We choosed consecutive patients with transient ischemic attack(TIA) or acute stroke within the middle cerebral artery territory by transcranialDoppler(TCD). Patients underwent microembolic signal monitoring by TCD,diffusion-weighted magnetic resonance imaging(DWI) and perfusion-weightedmagnetic resonance imaging(PWI). Characteristics of acute infarct on DWIwere categorized according to the number (single or multiple infarcts) and thepattern of cerebral infarcts (cortical, border zone, or perforating artery territoryinfarcts). All patients were followed-up for the occurrence of recurrent stroke ortransient ischemic attack (TIA) in the indexed MCA territory in one week afterexaminations.Results: We identified130patients.MES was detected in50(38.4%)patients. During follow-up for one week,37patients had further ischemicevents (25MES+) in the affected MCA region during follow-up. MES weremore common in patients with further ischemic events (67.6%) than in thosewithout further ischemic events (26.9%)(P<0.0001).60patients underwentDWI,45of them had acute infarct and26(43.3%) of them had MES. MESwere more common in patients with acute infarct(51.1%) then patients without acute infarct(20.0%)(P<0.05). There is the Logistic regression between thenumber of infarcts on DWI and the number of MES detected in30min (OR4.181,95%CL,1.03816.848; P=0.0442<0.05).34patients underwentPWI.Patients with acute infarct had longer relatively mean transit time(rMTT)and lower relative cerebral blood flow (rCBF) then patients without acuteinfarct, and rCBF of the two group had remarkable difference. The comparisonof rMTT and rCBF between the MES masculine group and the MES negativegroup also does not have difference with statistics significance.Conclusion: Hypoperfusion and embolization were both the impotentpathogenesises of acute ischemic stroke and TIA. However there was no directevidence that both mechanisms act in synergy. In acute stroke and TIA patientswith MCA stenosis, MES predicts further one week cerebral ischemia. |
