Cerebral VeinsCerebral AngiographyAngiographyMagnetic Resonance AngiographyAngiography, Digital SubtractionCoronary AngiographyCerebral ArteriesIntracranial AneurysmCerebral InfarctionSubarachnoid HemorrhageIntracranial Arteriovenous MalformationsTomography, X-Ray ComputedCarotid Artery, InternalCerebrovascular CirculationCranial SinusesVertebral ArteryMoyamoya DiseaseCerebral HemorrhagePosterior Cerebral ArteryIschemic Attack, TransientCircle of WillisCerebrovascular DisordersCentral Nervous System Vascular MalformationsAneurysm, RupturedMiddle Cerebral ArteryBrain IschemiaMagnetic Resonance ImagingFluorescein AngiographyCerebral RevascularizationIntracranial Embolism and ThrombosisBasilar ArteryArterial Occlusive DiseasesEmbolization, TherapeuticVasospasm, IntracranialCerebral Arterial DiseasesAnterior Cerebral ArteryCerebral PalsyCarotid StenosisBrainVasculitis, Central Nervous SystemCarotid Artery DiseasesContrast MediaVertebrobasilar InsufficiencySinus Thrombosis, IntracranialIntracranial ArteriosclerosisBlindness, CorticalArteriovenous FistulaCraniotomyEndarterectomyCollateral CirculationEpilepsy, Tonic-ClonicCarotid ArteriesBlood Flow VelocityArteriovenous MalformationsIntracranial EmbolismNeurosurgical ProceduresNeurologic ExaminationSensitivity and SpecificityInfarction, Middle Cerebral ArteryHematoma, SubduralCranial Fossa, AnteriorConstriction, PathologicProspective StudiesTreatment OutcomeCarotid-Cavernous Sinus FistulaCavernous Sinus