Basilar ArteryVertebrobasilar InsufficiencyStrokeVertebral ArteryCerebral AngiographyBrain Stem InfarctionsArterial Occlusive DiseasesPosterior Cerebral ArteryCerebral InfarctionCerebral ArteriesArteriesMagnetic Resonance AngiographyBrain IschemiaInfarction, Posterior Cerebral ArteryCerebrovascular CirculationTomography, X-Ray ComputedIntracranial AneurysmRetinal Artery OcclusionThrombolytic TherapySubarachnoid HemorrhageFibrinolytic AgentsComaCerebrovascular DisordersBrain InfarctionTreatment OutcomeMechanical ThrombolysisTissue Plasminogen ActivatorInjections, Intra-ArterialSkull Fracture, BasilarCarotid Artery, InternalIschemic Attack, TransientUltrasonography, Doppler, TranscranialInfarction, Middle Cerebral ArterySkull Fracture, DepressedIntracranial ArteriosclerosisAcute DiseaseAneurysm, RupturedEmbolization, TherapeuticCarotid ArteriesPulmonary ArteryPonsBrain StemMagnetic Resonance ImagingInfusions, Intra-ArterialProspective StudiesFemoral ArteryIntracranial EmbolismVertebral Artery DissectionMoyamoya DiseaseRenal ArteryAngiography, Digital SubtractionAnterior Cerebral ArteryBrainMesenteric ArteriesAngiographyVasospasm, IntracranialTime FactorsFollow-Up StudiesMiddle Cerebral ArteryVasodilationRetrospective StudiesDogsCarotid Artery DiseasesCerebral RevascularizationHeadacheVasoconstrictionConstriction, PathologicRisk FactorsCerebral Arterial DiseasesIliac ArteryInjections, IntravenousStentsMuscle, Smooth, VascularCollateral CirculationHemiplegiaCoronary Artery BypassAneurysm, DissectingIntracranial Embolism and ThrombosisCoronary VesselsVasodilator AgentsCircle of WillisRadial ArteryDisease Models, AnimalPredictive Value of TestsCerebral HemorrhageSubclavian ArteryCoronary OcclusionParesisCarotid StenosisRecurrenceMammary ArteriesRegional Blood FlowRecovery of FunctionRats, Sprague-DawleySerotoninRabbitsRegistriesCarotid Artery, CommonIntracranial ThrombosisBlood Pressure