Cerebral ArteriesCircle of WillisCollateral CirculationDNA, CircularMagnetic Resonance AngiographyManagement Quality CirclesNeuroendoscopyCarotid Artery, InternalCerebrovascular CirculationMoyamoya DiseaseCerebral AngiographyDoppler EffectAngiography, Digital SubtractionIntracranial ArteriosclerosisUltrasonography, Doppler, TranscranialBasilar ArteryHistory, 17th CenturyVertebral ArteryIntracranial AneurysmSphenoid BoneCarotid StenosisCarotid Artery, ExternalArachnoidEchoencephalographyMigraine with AuraOphthalmic ArteryCarotid-Cavernous Sinus FistulaIntracranial Arteriovenous MalformationsCranial Fossa, PosteriorSkull BaseBlood Flow VelocityCerebral InfarctionCerebrovascular DisordersPia MaterDominance, CerebralBrainImaging, Three-DimensionalBrain IschemiaSubarachnoid HemorrhageCadaverUltrasonography, Doppler, ColorArterial Occlusive DiseasesIschemic Attack, TransientCarotid Arteries