Cerebral AngiographySubarachnoid HemorrhageSubarachnoid SpaceAngiographyIntracranial AneurysmMagnetic Resonance AngiographyAngiography, Digital SubtractionVasospasm, IntracranialCerebral ArteriesCoronary AngiographyCerebral InfarctionTomography, X-Ray ComputedAneurysm, RupturedIntracranial Arteriovenous MalformationsCerebrovascular CirculationBasilar ArteryCerebral HemorrhageVertebral ArteryIschemic Attack, TransientCerebral VeinsCranial SinusesCarotid Artery, InternalPosterior Cerebral ArteryMoyamoya DiseaseCerebrovascular DisordersBrain IschemiaMiddle Cerebral ArteryCircle of WillisCentral Nervous System Vascular MalformationsEmbolization, TherapeuticMagnetic Resonance ImagingBrainCerebral RevascularizationCerebral Arterial DiseasesIntracranial Embolism and ThrombosisAnterior Cerebral ArteryFluorescein AngiographyArterial Occlusive DiseasesCraniotomyNeurosurgical ProceduresCarotid Artery DiseasesVasculitis, Central Nervous SystemCerebral PalsyHematoma, SubduralRupture, SpontaneousContrast MediaSurgical InstrumentsVertebrobasilar InsufficiencySinus Thrombosis, IntracranialCarotid StenosisArteriovenous FistulaIntracranial ArteriosclerosisNeurologic ExaminationProspective StudiesTreatment OutcomeArteriovenous MalformationsVertebral Artery DissectionBlood Flow VelocityBlindness, CorticalHeadacheCarotid ArteriesCollateral CirculationEpilepsy, Tonic-ClonicEndarterectomySensitivity and SpecificityIntracranial EmbolismTime FactorsHematoma, Subdural, IntracranialIntracranial HemorrhagesRetrospective StudiesInfarction, Middle Cerebral ArteryComaDura MaterConstriction, PathologicFollow-Up StudiesCranial Fossa, AnteriorCavernous SinusUltrasonography, Doppler, TranscranialHematomaCarotid-Cavernous Sinus FistulaAneurysm, InfectedCisterna MagnaIntracranial PressureMalaria, CerebralTemporal ArteriesStrokeRemission, SpontaneousCatheterizationSubarachnoid Hemorrhage, TraumaticLateral Medullary SyndromeHydrocephalusImaging, Three-DimensionalArachnoidSpinal PunctureRadionuclide AngiographyRisk FactorsAneurysm, DissectingRecurrenceUltrasonographyPredictive Value of Tests