Anterior Cerebral ArteryInfarction, Anterior Cerebral ArteryCerebral ArteriesCerebral AngiographyIntracranial AneurysmAneurysm, RupturedMiddle Cerebral ArteryCircle of WillisVertebral ArterySubarachnoid HemorrhageBasilar ArteryArteriesMagnetic Resonance AngiographyCerebral InfarctionTomography, X-Ray ComputedCerebral Arterial DiseasesCerebrovascular CirculationInfarction, Middle Cerebral ArteryAngiography, Digital SubtractionCerebellumCerebellar DiseasesEmbolization, TherapeuticCarotid Artery, InternalPosterior Cerebral ArteryAngiographyCerebral RevascularizationUltrasonography, Doppler, TranscranialVertebrobasilar InsufficiencyLateral Medullary SyndromeIntracranial Arteriovenous MalformationsCarotid ArteriesCoronary AngiographyNeurosurgical ProceduresBrain IschemiaCraniotomyAneurysm, DissectingBlood Flow VelocityMagnetic Resonance ImagingAkinetic MutismArterial Occlusive DiseasesIntracranial Embolism and ThrombosisBrain Stem InfarctionsEchoencephalographyVasospasm, IntracranialSurgical InstrumentsIschemic Attack, TransientPulmonary ArteryBrainVertebral Artery DissectionHemifacial SpasmRupture, SpontaneousTreatment OutcomeBrain Hemorrhage, TraumaticIntracranial ArteriosclerosisCerebrovascular DisordersMoyamoya DiseaseRenal ArteryDominance, CerebralFemoral ArteryCerebral HemorrhageMesenteric ArteriesUltrasonography, DopplerTrigeminal NeuralgiaCarotid Artery DiseasesCarotid StenosisRetrospective StudiesImaging, Three-DimensionalRegional Blood FlowCaloric TestsCollateral CirculationCoronary Artery BypassIliac ArteryStrokeBrain InfarctionFollow-Up StudiesVertigoRadial ArteryHematomaUltrasonographyCerebellopontine AngleMicrosurgeryMammary ArteriesSubclavian ArteryCoronary VesselsFacial Nerve DiseasesFrontal LobeTemporal ArteriesTime FactorsCentral Nervous System Vascular MalformationsFluorescein AngiographyNerve Compression SyndromesCarotid Artery, CommonSplenic ArteryHepatic ArteryElectronystagmographySensitivity and SpecificityPostoperative ComplicationsBrachial ArteryVasoconstrictionCeliac Artery