Vertebral ArteryVertebrobasilar InsufficiencyBasilar ArteryCerebral AngiographyVertebral Artery DissectionEchoencephalographySubarachnoid Hemorrhage, TraumaticMagnetic Resonance AngiographyIntracranial AneurysmAneurysm, DissectingSubclavian ArteryArteriesAngioplasty, BalloonSubclavian Steal SyndromeStentsAngiography, Digital SubtractionCarotid ArteriesVertigoCerebral ArteriesArterial Occlusive DiseasesAngiographyCarotid Artery, InternalPulmonary ArteryIntracranial ArteriosclerosisTomography, X-Ray ComputedSubarachnoid HemorrhageIschemic Attack, TransientEmbolization, TherapeuticAneurysm, RupturedRenal ArteryIntracranial Embolism and ThrombosisFemoral ArteryConstriction, PathologicCarotid Artery DiseasesInfarction, Posterior Cerebral ArteryCerebral InfarctionMesenteric ArteriesOccipital BoneCerebrovascular DisordersCerebrovascular CirculationCerebellar DiseasesHemifacial SpasmUltrasonography, Doppler, TranscranialPetrous BonePosterior Cerebral ArteryTreatment OutcomeTrigeminal NeuralgiaLateral Medullary SyndromeBrain IschemiaMagnetic Resonance ImagingCerebral Hemorrhage, TraumaticMammary ArteriesNerve Compression SyndromesIliac ArteryCircle of WillisCoronary Artery BypassStrokeTrochlear Nerve InjuriesCerebral RevascularizationCarotid Artery, CommonBrachiocephalic TrunkRadial ArteryAngioplastyLabyrinthitisFollow-Up StudiesHeadacheRetrospective StudiesCarotid StenosisBlood Flow VelocityBrain InfarctionCarotid Artery, Internal, DissectionCerebellumCervical VertebraeBrain Stem InfarctionsCervical AtlasComaNeck InjuriesSplenic ArteryBrachial ArteryUltrasonographyFibromuscular Dysplasia