Magnetic Resonance AngiographyAngiography, Digital SubtractionMagnetic Resonance ImagingContrast MediaAngiographyCerebral AngiographyImaging, Three-DimensionalGadoliniumSubtraction TechniqueGadolinium DTPACoronary AngiographyMagnetic Resonance SpectroscopySensitivity and SpecificityImage EnhancementIntracranial AneurysmTomography, X-Ray ComputedCircle of WillisCarotid StenosisUltrasonography, Doppler, DuplexCarotid Artery, InternalArterial Occlusive DiseasesArtifactsConstriction, PathologicImage Interpretation, Computer-AssistedImage Processing, Computer-AssistedCerebral Arterial DiseasesVertebrobasilar InsufficiencyObserver VariationVertebral ArteryRenal Artery ObstructionReproducibility of ResultsPredictive Value of TestsCerebral ArteriesMagnetic Resonance Imaging, CineAnterior Cerebral ArteryIntracranial Arteriovenous MalformationsOrganometallic CompoundsPosterior Cerebral ArteryMeglumineProspective StudiesCerebrovascular CirculationRenal ArteryIntracranial Arterial DiseasesPulmonary VeinsPreoperative CareRadiographic Image EnhancementUltrasonography, Doppler, ColorCarotid ArteriesEndarterectomy, CarotidBrainIntracranial ArteriosclerosisEmbolization, TherapeuticCollateral CirculationAneurysm, RupturedUltrasonography, Doppler, TranscranialRetrospective StudiesFeasibility StudiesTibial ArteriesSeverity of Illness IndexBlood Flow VelocityInfarction, Posterior Cerebral ArteryTreatment OutcomeBasilar ArteryPeripheral Vascular DiseasesCarotid Artery DiseasesCerebrovascular DisordersMoyamoya DiseaseUltrasonography, DopplerScimitar SyndromeCoronary VesselsVertebral Artery DissectionPortographyCerebral VeinsTime FactorsLegDiagnostic ImagingVascular MalformationsStentsCarotid Artery, ExternalPhlebographyFluorescein AngiographyFibromuscular DysplasiaAortographyFollow-Up StudiesEcho-Planar ImagingLateral Medullary SyndromeIliac ArteryStrokeCeliac ArteryBrain IschemiaIschemic Attack, TransientVascular PatencySubarachnoid HemorrhageMiddle Cerebral ArteryIncidental FindingsCerebral RevascularizationPhantoms, ImagingSingle-Blind MethodCoronary Artery DiseaseHypertension, Renovascular