Thrombolytic therapy with intravenous tissue plasminogen activator (IV tPA) is initiated within 3 hours from the onset of ischemic stroke now. Following the publication of the results of ECASS III in 2008, IV tPA treatment has been initiated within 4.5 hours abroad. Expanding the therapeutic time window from 3 to 4.5 hours had been applied, but not approved yet in Japan. Evidence of mechanical intraarterial (IA) thrombectomy within 8 hours is not sufficient. Since a mismatch between PWI and DWI is very attractive for selecting patients for recanalization, the standardization of neuroimaging analysis must be established. For efficacious and safe recanalization, it is necessary to select patients based on accurate information on neuroimages and to establish the most useful therapy (IV tPA and/or IA thrombectomy) for each patient.