High B Value Diffusion and Stroke

Inclusion Criteria: * Patients older than 18 years old * Cerebral infarct or cerebral hypoperfusion with neurological symptoms within the anterior circulation * Due to occlusion or stenosis of intracranial carotid artery or its branches and/or middle cerebral artery (MCA) and/or anterior cerebral artery. * With acute MRI performed within the first 24h and showing significant penumbra defined as ratio between the volumes of critically hypoperfused tissue (defined by Tmax\>6s) and the ischemic core (defined by ADC\<600 × 10-6 mm2/s) of 1.8 or more, with an absolute difference of 15 mL or more and ischemic core volume of less than 70 mL. * Successful recanalization by thrombectomy (TICI 2b or 2c or 3) and/or by IV thrombolysis (if within the first 4.5h) or spontaneously. * Patient/Legally Authorized Representative has signed the Informed Consent form. Exclusion Criteria: * History of symptomatic cerebral infarct with functional deficit (pre-stroke modified Rankin Scale score ≥1) to measure the impact of the infarct and selective neuronal loss on long-term outcome without being biased by pre-existing deficits. * History of severe cognitive impairment (dementia) or DSMIV axis 1 psychiatric disorders that would confound the neurological evaluations. * Pregnant or breast-feeding women. * Contraindications to MRI.