Basilar ArteryVertebrobasilar InsufficiencyVertebral ArteryIntracranial AneurysmPosterior Cerebral ArteryCerebral AngiographyArteriesAneurysm, RupturedCerebellumBrain Stem InfarctionsSubarachnoid HemorrhageInfarction, Posterior Cerebral ArteryCerebellar DiseasesCerebral ArteriesEmbolization, TherapeuticVertebral Artery DissectionMagnetic Resonance AngiographyLateral Medullary SyndromeCerebral InfarctionBrain InfarctionTomography, X-Ray ComputedCerebrovascular CirculationHemifacial SpasmPulmonary ArteryMagnetic Resonance ImagingAneurysm, DissectingCerebral RevascularizationIntracranial ArteriosclerosisCarotid Artery, InternalAngiography, Digital SubtractionCarotid ArteriesMoyamoya DiseaseTrigeminal NeuralgiaTreatment OutcomeFemoral ArteryRenal ArteryMesenteric ArteriesStrokeCranial Fossa, PosteriorRupture, SpontaneousAnterior Cerebral ArteryBrain IschemiaVertigoCaloric TestsUltrasonography, Doppler, TranscranialArterial Occlusive DiseasesRetrospective StudiesCerebellopontine AngleAngiographyIschemic Attack, TransientIliac ArteryCoronary Artery BypassMicrosurgeryFollow-Up StudiesIntracranial EmbolismRadial ArteryFacial Nerve DiseasesCraniotomyMammary ArteriesVasodilationNerve Compression SyndromesSubclavian ArteryConstriction, PathologicVasoconstrictionCerebrovascular DisordersCarotid Artery DiseasesNeurosurgical ProceduresIntracranial Arteriovenous MalformationsElectronystagmographySurgical InstrumentsVasospasm, IntracranialBrachial ArterySplenic ArteryStentsMuscle, Smooth, VascularCoronary VesselsAkinetic MutismMiddle Cerebral ArteryCranial Nerve DiseasesHepatic ArteryCarotid Artery, CommonAcute DiseaseBlood CirculationProspective StudiesVasodilator AgentsOphthalmic ArteryCentral Nervous System Vascular MalformationsBrainDogsCeliac ArteryRisk FactorsMesenteric Artery, SuperiorImaging, Three-DimensionalUmbilical ArteriesTrigeminal NerveBronchial ArteriesRenal Artery ObstructionThoracic ArteriesEndothelium, VascularTemporal Arteries