Adult patients who are diagnosed with an acute supratentorial ischemic stroke within 48 hrs of onset will be enrolled into the study. Participants will undergo both a CT Scan and PET scan within 7 days of onset. Participants will have the option to undergo a second PET scan with fluorodeoxyglucose (FDG).

Patients older than 18 years of age diagnosed with an acute supratentorial ischemic stroke within 48 hrs of symptom onset will be prospectively enrolled. Research imaging will be obtained before 7 days after symptom onset. The patient will receive the standardized treatment protocol at the hospital. Informed consent will be obtained from each patient or a substitute decision maker for each individual imaging study (CTP, Rb PET, and FDG PET). The patient will be given the option of undergoing the CTP imaging with the Rb PET only or both the Rb PET and FDG PET components.

Inclusion Criteria:

• Age: >18 yo
• Gender: male or female
• Acute (within 7 days from symptom onset) Supratentorial Ischemic Stroke

Exclusion Criteria:

• 1) Planned surgical intervention
• 2) Severely abnormal blood glucose level (will be excluded from FDG PET imaging)
• 3) Unable to undergo CTP or PET imaging (i.e. claustrophobia)
• 4) Pregnancy

Patients who are older than 18 years of age diagnosed with an acute supratentorial ischemic stroke within 48 hrs of onset will be enrolled into the study. Both male and female patients will be enrolled. We want diversity among participants in order to gain insightful information about acute supratentorial ischemic stroke as possible. A broad range in age, along with enrolling both male and female participants will allow greater diversity.