Vertebral ArteryBasilar ArteryVertebral Artery DissectionVertebrobasilar InsufficiencyArteriesCerebral AngiographyCerebral ArteriesSubclavian ArteryCarotid ArteriesPulmonary ArterySubclavian Steal SyndromeCarotid Artery, InternalArterial Occlusive DiseasesBrain Stem InfarctionsSubarachnoid HemorrhageIntracranial AneurysmMagnetic Resonance AngiographyFemoral ArteryRenal ArteryMesenteric ArteriesAngiographyEmbolization, TherapeuticAngiography, Digital SubtractionAneurysm, DissectingCarotid Artery DiseasesTomography, X-Ray ComputedLateral Medullary SyndromeIliac ArteryMammary ArteriesCoronary Artery BypassAneurysm, RupturedCarotid Artery, CommonCerebrovascular CirculationRadial ArteryStentsBalloon OcclusionCerebral InfarctionTreatment OutcomeVasodilationRetinal Artery OcclusionCarotid Artery, Internal, DissectionConstriction, PathologicBrain IschemiaCervical VertebraeDogsVasoconstrictionCoronary VesselsIntracranial ArteriosclerosisMiddle Cerebral ArteryBrachial ArteryCervical AtlasCarotid Artery, ExternalSplenic ArteryNeck InjuriesVasospasm, IntracranialMuscle, Smooth, VascularFibromuscular DysplasiaHepatic ArteryCoronary OcclusionIschemic Attack, TransientRegional Blood FlowUltrasonography, Doppler, TranscranialCircle of WillisIntracranial Embolism and ThrombosisCerebral RevascularizationAneurysmAxisAngioplasty, BalloonCeliac ArteryCarotid StenosisOphthalmic ArteryInfarction, Middle Cerebral ArteryMesenteric Artery, SuperiorVasodilator AgentsMagnetic Resonance ImagingAneurysm, FalseFollow-Up StudiesOccipital BoneCerebrovascular DisordersTime FactorsCerebral Arterial DiseasesRenal Artery ObstructionCerebellar DiseasesUltrasonography, Doppler, ColorPopliteal ArteryStrokeTemporal ArteriesUltrasonography, DopplerUmbilical ArteriesThoracic ArteriesArteriovenous FistulaRetinal Vein OcclusionVertigoVascular PatencyEndothelium, VascularCoronary AngiographyUlnar ArteryIntracranial ThrombosisBlood Flow VelocityRetrospective Studies