In patients with acute ischemic stroke, more distal thrombus location, greater thrombus permeability, and longer time to recanalization assessment were associated with recanalization of arterial occlusion after administration of intravenous alteplase; among patients who did not receive alteplase, rates of arterial recanalization were low. These findings may help inform treatment and triage decisions in patients with acute ischemic stroke.

http://j-stroke.org 43 100,000 individuals, with regional disparities. As for stroke risk factors, the prevalence of smoking is decreasing in men but not in women, and the prevalence of alcohol drinking is increasing in women but not in men. Population-attributable risk factors vary with age. Smoking plays a role in young-aged individuals, hypertension and diabetes in middle-aged individuals, and atrial fibrillation in the elderly. About four out of 10 hospitalized patients with stroke are visiting an emergency room within 3 hours of symptom onset, and only half use an ambulance. Regarding acute management, the proportion of patients with ischemic stroke receiving intravenous thrombolysis and endovascular treatment was 10.7% and 3.6%, respectively. Decompressive surgery was performed in 1.4% of patients with ischemic stroke and in 28.1% of those with intracerebral hemorrhage. The cumulative incidence of bleeding and fracture at 1 year after stroke was 8.9% and 4.7%, respectively. The direct costs of stroke were about ₩1.68 trillion (KRW), of which ₩1.11 trillion were for ischemic stroke and ₩540 billion for hemorrhagic stroke. The great burden of stroke in Korea can be reduced through more concentrated efforts to control major attributable risk factors for age and sex, reorganize emergency medical service systems to give patients with stroke more opportunities for reperfusion therapy, disseminate stroke unit care, and reduce regional disparities. We hope that this report can contribute to achieving these tasks.

P rogression to infarction after acute ischemic stroke onset is time-sensitive and has substantial intersubject variability. 1,2 Computed tomographic (CT) perfusion (CTP) measurement of brain parenchyma can be used to estimate ischemic core and penumbra and, therefore, provide immediate information for treatment decision-making. Current CTP thresholds that estimate these tissue states are generally derived either by comparison with magnetic resonance (MR) diffusion-weighted imaging (DWI), often done within an hour of CTP, or with follow-up infarction in patients who have reperfused sometime within 24 hours.3-11 Because infarcts grow over time and final tissue fate depends greatly on what happens in the minutes to hours immediately after this imaging snapshot, CTP thresholds predicting infarction are likely to depend on the time from stroke symptom onset to imaging, time from imaging to reperfusion, and the quality of reperfusion.Background and Purpose-Among patients with acute ischemic stroke, we determine computed tomographic perfusion (CTP) thresholds associated with follow-up infarction at different stroke onset-to-CTP and CTP-to-reperfusion times. Methods-Acute ischemic stroke patients with occlusion on computed tomographic angiography were acutely imaged with CTP. Noncontrast computed tomography and magnectic resonance diffusion-weighted imaging between 24 and 48 hours were used to delineate follow-up infarction. Reperfusion was assessed on conventional angiogram or 4-hour repeat computed tomographic angiography. T max , cerebral blood flow, and cerebral blood volume derived from delayinsensitive CTP postprocessing were analyzed using receiver-operator characteristic curves to derive optimal thresholds for combined patient data (pooled analysis) and individual patients (patient-level analysis) based on time from stroke onset-to-CTP and CTP-to-reperfusion. One-way ANOVA and locally weighted scatterplot smoothing regression was used to test whether the derived optimal CTP thresholds were different by time. Results-One hundred and thirty-two patients were included. T max thresholds of >16.2 and >15.8 s and absolute cerebral blood flow thresholds of <8.9 and <7.4 mL•min −1•100 g −1 were associated with infarct if reperfused <90 min from CTP with onset <180 min. The discriminative ability of cerebral blood volume was modest. No statistically significant relationship was noted between stroke onset-to-CTP time and the optimal CTP thresholds for all parameters based on discrete or continuous time analysis (P>0.05). A statistically significant relationship existed between CTP-to-reperfusion time and the optimal thresholds for cerebral blood flow (P<0.001; r=0.59 and 0.77 for gray and white matter, respectively) and T max (P<0.001; r=−0.68 and −0.60 for gray and white matter, respectively) parameters. Conclusions-Optimal CTP thresholds associated with follow-up infarction depend on time from imaging to reperfusion.

Acute thrombi showed different histologic features according to the stroke etiology. The distribution of platelets and proportion of red blood cells and fibrin were major distinguishing factors between stroke subtypes.