Anterior Cerebral ArteryInfarction, Anterior Cerebral ArteryCerebral ArteriesIntracranial AneurysmCerebral AngiographyAneurysm, RupturedMiddle Cerebral ArteryPalatine TonsilCircle of WillisVertebral ArterySubarachnoid HemorrhageBasilar ArteryArteriesCerebral InfarctionCerebral Arterial DiseasesInfarction, Middle Cerebral ArteryCerebrovascular CirculationCerebellumTomography, X-Ray ComputedCerebellar DiseasesEmbolization, TherapeuticPosterior Cerebral ArteryMagnetic Resonance AngiographyCarotid Artery, InternalCerebral RevascularizationUltrasonography, Doppler, TranscranialLateral Medullary SyndromeCarotid ArteriesVertebrobasilar InsufficiencyAngiography, Digital SubtractionIntracranial Arteriovenous MalformationsNeurosurgical ProceduresBrain IschemiaCraniotomyAneurysm, DissectingAkinetic MutismBlood Flow VelocityMagnetic Resonance ImagingBrain Stem InfarctionsIntracranial Embolism and ThrombosisEchoencephalographyVasospasm, IntracranialArterial Occlusive DiseasesSurgical InstrumentsIschemic Attack, TransientBrainPulmonary ArteryHemifacial SpasmVertebral Artery DissectionRupture, SpontaneousBrain Hemorrhage, TraumaticTreatment OutcomeDominance, CerebralIntracranial ArteriosclerosisCerebrovascular DisordersMoyamoya DiseaseRenal ArteryFemoral ArteryMesenteric ArteriesCerebral HemorrhageTrigeminal NeuralgiaUltrasonography, DopplerCaloric TestsCarotid Artery DiseasesRegional Blood FlowVertigoBrain InfarctionCarotid StenosisStrokeCerebellopontine AngleRetrospective StudiesIliac ArteryCoronary Artery BypassCollateral CirculationHematomaRadial ArteryUltrasonographyFacial Nerve DiseasesMicrosurgeryMammary ArteriesFollow-Up StudiesFrontal LobeSubclavian ArteryTemporal ArteriesImaging, Three-DimensionalNerve Compression SyndromesElectronystagmographyCarotid Artery, CommonCranial Fossa, PosteriorCerebral PalsyBrachial ArterySplenic ArteryUmbilical ArteriesTime FactorsVasoconstrictionCranial Nerve DiseasesHepatic ArteryCoronary VesselsOphthalmic ArteryPostoperative Complications