Vertebral ArteryVertebral Artery DissectionVertebrobasilar InsufficiencyPerfusionArteriesBasilar ArterySubclavian ArteryCerebral AngiographySubclavian Steal SyndromeMagnetic Resonance AngiographyPerfusion ImagingLateral Medullary SyndromeCarotid ArteriesAneurysm, DissectingCerebral ArteriesAngiographyPulmonary ArteryCarotid Artery, InternalIntracranial AneurysmAngiography, Digital SubtractionCervical VertebraeEmbolization, TherapeuticMyocardial Perfusion ImagingArterial Occlusive DiseasesTomography, X-Ray ComputedBrain Stem InfarctionsCervical AtlasSubarachnoid HemorrhageNeck InjuriesFemoral ArteryCarotid Artery, Internal, DissectionAxisMesenteric ArteriesRenal ArteryFibromuscular DysplasiaAneurysm, RupturedCerebrovascular CirculationCarotid Artery, CommonOccipital BoneCarotid Artery DiseasesMammary ArteriesRegional Blood FlowCerebellar DiseasesStentsMagnetic Resonance ImagingCoronary Artery BypassIliac ArteryAneurysm, FalseConstriction, PathologicAtlanto-Axial JointTreatment OutcomeDoppler EffectCerebral RevascularizationCerebral InfarctionCarotid Artery, ExternalPercussionArteriovenous FistulaRadial ArteryVertigoUltrasonography, Doppler, ColorIntracranial ArteriosclerosisAneurysmUltrasonography, DopplerBlood Flow VelocityAtlanto-Occipital JointCoronary VesselsCoronary CirculationBrain IschemiaMastoidAngioplasty, BalloonTomography, Emission-Computed, Single-PhotonFollow-Up StudiesHepatic ArteryUltrasonographyNeckWounds, StabCerebrovascular DisordersBrachial ArterySplenic ArteryUltrasonography, Doppler, TranscranialTime FactorsCarotid StenosisHemifacial SpasmCerebellumUltrasonography, Doppler, DuplexContrast MediaInfarctionIntracranial Embolism and ThrombosisBalloon OcclusionKryptonHemodynamicsMiddle Cerebral ArteryDogsHeadacheCeliac ArteryOphthalmic ArteryMesenteric Artery, SuperiorStrokeSensitivity and SpecificityCoronary Angiography