Angiography, Digital SubtractionMagnetic Resonance AngiographyCerebral AngiographySubtraction TechniqueAngiographyIntracranial AneurysmCoronary AngiographyIntracranial Arteriovenous MalformationsImaging, Three-DimensionalContrast MediaTomography, X-Ray ComputedEmbolization, TherapeuticSensitivity and SpecificityCarotid Artery, InternalCentral Nervous System Vascular MalformationsRadiographic Image EnhancementAneurysm, RupturedArterial Occlusive DiseasesCarotid StenosisTomography, Spiral ComputedSubarachnoid HemorrhageImage Processing, Computer-AssistedCerebral VeinsIopamidolUltrasonography, Doppler, DuplexConstriction, PathologicUltrasonography, Doppler, ColorReproducibility of ResultsArteriovenous MalformationsVertebrobasilar InsufficiencyFluorescein AngiographyCarotid Artery DiseasesIohexolObserver VariationCerebral ArteriesGadolinium DTPAArtifactsCranial SinusesRadiographic Image Interpretation, Computer-AssistedVertebral ArteryAnterior Cerebral ArteryPredictive Value of TestsSurgical InstrumentsVasospasm, IntracranialCarotid-Cavernous Sinus FistulaArteriovenous FistulaBasilar ArteryUltrasonography, Doppler, TranscranialCerebrovascular DisordersMagnetic Resonance ImagingRetrospective StudiesX-Ray Intensifying ScreensAneurysmRadiography, InterventionalIothalamate MeglumineInjections, Intra-ArterialCerebrovascular CirculationProspective StudiesTibial ArteriesImage EnhancementCircle of WillisIntracranial ArteriosclerosisTriiodobenzoic AcidsTreatment OutcomeCerebral RevascularizationCarotid Artery, ExternalRenal ArteryCarotid ArteriesNeurosurgical ProceduresBlood Flow VelocityMoyamoya DiseaseUltrasonography, DopplerCollateral CirculationEndarterectomyIschemic Attack, TransientVascular PatencyAortographyRadiation DosageUltrasonographyFollow-Up StudiesStentsBrain IschemiaFeasibility StudiesRadionuclide AngiographyPopliteal ArteryGadoliniumCavernous SinusFalse Negative ReactionsPreoperative CarePhantoms, ImagingSeverity of Illness IndexArteriesFemoral ArterySubclavian ArteryOrganometallic CompoundsAngioplasty, BalloonCerebral InfarctionCoronary Artery DiseaseTime FactorsMiddle Cerebral Artery