Vertebral ArteryVertebrobasilar InsufficiencyBasilar ArteryVertebral Artery DissectionArteriesSubarachnoid Hemorrhage, TraumaticCerebral AngiographyMagnetic Resonance AngiographyIntracranial AneurysmAneurysm, DissectingSubclavian ArteryAngioplasty, BalloonPulmonary ArteryCarotid ArteriesStentsCerebral ArteriesSubclavian Steal SyndromeRenal ArteryFemoral ArteryCarotid Artery, InternalMesenteric ArteriesAngiographyAngiography, Digital SubtractionArterial Occlusive DiseasesCarotid Artery DiseasesIliac ArteryMammary ArteriesCoronary Artery BypassTomography, X-Ray ComputedRadial ArteryCarotid Artery, CommonEmbolization, TherapeuticVertigoSubarachnoid HemorrhageAneurysm, RupturedIntracranial ArteriosclerosisLateral Medullary SyndromeSplenic ArteryBrachial ArteryConstriction, PathologicTreatment OutcomeHepatic ArteryCerebral InfarctionCoronary VesselsCerebrovascular CirculationIschemic Attack, TransientCarotid Artery, Internal, DissectionOccipital BoneCeliac ArteryIntracranial Embolism and ThrombosisOphthalmic ArteryCarotid Artery, ExternalCerebellar DiseasesMesenteric Artery, SuperiorCerebrovascular DisordersUltrasonography, Doppler, TranscranialUmbilical ArteriesMiddle Cerebral ArteryBrain IschemiaRenal Artery ObstructionCarotid StenosisCervical VertebraeThoracic ArteriesBrain Stem InfarctionsMagnetic Resonance ImagingFollow-Up StudiesTemporal ArteriesCerebral RevascularizationEchoencephalographyHemifacial SpasmFibromuscular DysplasiaBronchial ArteriesCervical AtlasNeck InjuriesCircle of WillisAneurysmPopliteal ArteryBrachiocephalic TrunkInfarction, Posterior Cerebral ArteryUlnar ArteryRetrospective StudiesAngioplastyStrokeAneurysm, FalseCarotid Artery InjuriesUterine ArteryAxisCoronary AngiographyPosterior Cerebral ArteryRegional Blood FlowTime FactorsVasodilationUltrasonography, DopplerUltrasonography, Doppler, ColorUltrasonographyNerve Compression SyndromesMuscle, Smooth, VascularCerebellumPetrous BoneVasoconstriction