Basilar ArteryVertebral ArteryVertebrobasilar InsufficiencyCerebral AngiographyIntracranial AneurysmSubclavian ArteryVertebral Artery DissectionSubclavian Steal SyndromeVertigoMagnetic Resonance AngiographyAngiography, Digital SubtractionBlood CirculationInfarction, Posterior Cerebral ArteryIschemic Attack, TransientIntracranial ArteriosclerosisPetrous BoneEchoencephalographyCerebrovascular CirculationTrigeminal NeuralgiaAneurysm, DissectingCerebral Hemorrhage, TraumaticArterial Occlusive DiseasesPosterior Cerebral ArteryIntracranial Embolism and ThrombosisTrochlear Nerve InjuriesAngioplasty, BalloonAngiographyLabyrinthitisCerebrovascular DisordersTomography, X-Ray ComputedCerebral InfarctionStentsNerve Compression SyndromesSubarachnoid HemorrhageUltrasonography, Doppler, TranscranialHemifacial SpasmExtracorporeal CirculationSubarachnoid Hemorrhage, TraumaticConstriction, PathologicComaBlood Flow VelocityPulmonary CirculationStrokeCircle of WillisBrain IschemiaTrigeminal NerveAneurysm, RupturedCerebellar DiseasesBrain InfarctionOccipital BoneMagnetic Resonance ImagingTreatment OutcomeTemporal BoneBrachiocephalic TrunkEmbolization, TherapeuticHeadacheCarotid Artery, InternalAngioplastyRetrospective StudiesInfusions, Intra-ArterialCollateral CirculationCerebral ArteriesThrombectomyDilatation, Pathologic