Patients were identified as potential study subjects and enrolled by the site neurologist or his/her designee at each site. Informed consent was obtained from the parent or guardian. Children enrolled met the following criteria: age at stroke onset ≥ 2 years and < 19 years, presentation within 96 hours after symptom onset with acute neurologic deficit of any duration consistent with focal brain ischemia in an arterial distribution, and MRI or CT performed within 96 hours of symptom onset demonstrating acute infarction in an arterial territory corresponding to the clinical deficit. Exclusion criteria included: acute traumatic brain injury; primary intracerebral or intraventricular hemorrhage; meningitis or encephalitis; status epilepticus (continuous clinical or electrographic seizure activity for ≥ 30 minutes); severe metabolic, toxic, or global hypoxic-ischemic encephalopathy; pre-existing severe neurologic deficit due to malignancy, congenital brain malformation, neurodegenerative disease, metabolic encephalopathy, severe residual deficits from perinatal or postnatal acquired encephalopathy; or stroke after craniotomy for any neurosurgical procedure.