Clinical Research Directory

Inclusion Criteria: * Age ≥ 18 years. * Acute ischemic stroke within 4.5 hours from onset. If onset time is unknown because of impaired consciousness or aphasia, use the "last known well" time. * A single perforating-artery infarct on brain MRI: located in the corona radiata, putamen, internal capsule, thalamus, or pons; solitary, mainly round or oval, with a maximum diameter ≤ 20 mm; lesions only in the centrum semiovale are not allowed, but extension from the above sites into the centrum semiovale is allowed. * No disability in daily life before the stroke (modified Rankin Scale ≤ 1). * National Institutes of Health Stroke Scale (NIHSS) score ≤ 5. * Written informed consent obtained. Exclusion Criteria: * Antithrombotic therapy considered inappropriate because of active bleeding, low platelet count, or similar conditions. * Any contraindication to intravenous rt-PA, without blood pressures. * ≥ 50 % stenosis or occlusion of the artery responsible for the stroke \* (see note below). * Diseases that require anticoagulation (e.g., atrial fibrillation, deep-vein thrombosis) \* * Inability to take medicine orally. * Any other reason judged by the principal investigator or co-investigators to make participation inappropriate. Note: This study targets hyper-acute stroke within 4.5 hours. To avoid treatment delay, items marked with \* must be judged using the similar examinations that each site normally performs before rt-PA administration.