Infarction, Anterior Cerebral ArteryMiddle Cerebral ArteryInfarction, Middle Cerebral ArteryCerebral ArteriesPerfusionTechnetium Tc 99m Aggregated AlbuminExtracorporeal CirculationCerebrovascular CirculationBrain IschemiaCerebral InfarctionRegional Blood FlowCerebral Arterial DiseasesUltrasonography, Doppler, TranscranialCerebral AngiographyIschemic Attack, TransientArterial Occlusive DiseasesAnterior Cerebral ArteryBlood Flow VelocityArteriesBrainPosterior Cerebral ArteryBrain EdemaReperfusionIntracranial Embolism and ThrombosisStrokeNeuroprotective AgentsBasilar ArteryCarotid Artery, InternalDisease Models, AnimalIntracranial AneurysmPerfusion ImagingTomography, X-Ray ComputedBrain InfarctionMagnetic Resonance AngiographyCerebrovascular DisordersRats, Sprague-DawleyTime FactorsCarotid ArteriesCerebral RevascularizationMagnetic Resonance ImagingTemporal ArteriesCerebral HemorrhageSubarachnoid HemorrhageConstrictionReperfusion InjuryRats, WistarUmbilical ArteriesBlood PressureLaser-Doppler FlowmetryPulmonary ArteryIntracranial EmbolismCerebral CortexAneurysm, RupturedCircle of WillisUltrasonography, DopplerVasoconstrictionCerebral VeinsCarotid Artery DiseasesVertebral ArteryTissue Plasminogen ActivatorNeurologic ExaminationTomography, Emission-Computed, Single-PhotonTreatment OutcomePia MaterVasodilationMyocardial Perfusion ImagingIntracranial ThrombosisCarotid Artery ThrombosisCatsCerebral PalsyCollateral CirculationEchoencephalographyBlood-Brain BarrierFemoral ArteryMesenteric ArteriesCarotid StenosisPulsatile FlowFibrinolytic AgentsIntracranial ArteriosclerosisCarbon DioxideCarotid Artery, ExternalAngiography, Digital Subtraction