Basilar ArteryPonsVertebral ArteryArteriesIntracranial AneurysmVertebrobasilar InsufficiencyCerebellumCerebellar DiseasesCerebral AngiographyAneurysm, RupturedBrain Stem InfarctionsLateral Medullary SyndromeSubarachnoid HemorrhageCerebral ArteriesPosterior Cerebral ArteryEmbolization, TherapeuticHemifacial SpasmPulmonary ArteryVertebral Artery DissectionCarotid ArteriesTomography, X-Ray ComputedTrigeminal NeuralgiaRenal ArteryMesenteric ArteriesFemoral ArteryMagnetic Resonance AngiographyCerebral InfarctionRupture, SpontaneousAneurysm, DissectingVertigoCaloric TestsMagnetic Resonance ImagingCerebral RevascularizationAngiography, Digital SubtractionCerebellopontine AngleIliac ArteryCarotid Artery, InternalCoronary Artery BypassMicrosurgeryFacial Nerve DiseasesRadial ArteryMammary ArteriesCraniotomyCranial Fossa, PosteriorVasodilationSubclavian ArteryTreatment OutcomeNerve Compression SyndromesCarotid Artery DiseasesIntracranial Arteriovenous MalformationsCerebrovascular CirculationElectronystagmographyBrain InfarctionVasoconstrictionNeurosurgical ProceduresSurgical InstrumentsVasospasm, IntracranialSplenic ArteryBrachial ArteryMuscle, Smooth, VascularAkinetic MutismCranial Nerve DiseasesHepatic ArteryCarotid Artery, CommonCoronary VesselsMiddle Cerebral ArteryArterial Occlusive DiseasesTrigeminal NerveCentral Nervous System Vascular MalformationsCeliac ArteryOphthalmic ArteryVasodilator AgentsMesenteric Artery, SuperiorUmbilical ArteriesBrain StemRenal Artery ObstructionDogsThoracic ArteriesImaging, Three-DimensionalTemporal ArteriesFollow-Up StudiesMedulla OblongataBronchial ArteriesRetrospective StudiesPopliteal ArteryEndothelium, VascularUlnar ArteryAngiographyVasoconstrictor AgentsSerotoninUterine ArteryCoronary AngiographyCarotid Artery, ExternalCircle of WillisPotassium ChlorideMuscle ContractionAcetylcholineRabbitsPapaverineCarotid Artery Injuries