Posterior Cerebral ArteryInfarction, Posterior Cerebral ArteryBasilar ArteryCerebral ArteriesCircle of WillisCerebral AngiographyMiddle Cerebral ArteryCerebral InfarctionCerebral Arterial DiseasesHemianopsiaIntracranial AneurysmCerebrovascular CirculationArteriesVertebral ArteryInfarction, Middle Cerebral ArteryAnterior Cerebral ArteryVertebrobasilar InsufficiencyUltrasonography, Doppler, TranscranialMagnetic Resonance AngiographyAneurysm, RupturedTomography, X-Ray ComputedCarotid Artery, InternalSubarachnoid HemorrhageBrain IschemiaMagnetic Resonance ImagingOccipital LobeEmbolization, TherapeuticBlood Flow VelocityDyslexia, AcquiredArterial Occlusive DiseasesBrainOphthalmoplegic MigraineMoyamoya DiseasePulmonary ArteryCarotid ArteriesAngiography, Digital SubtractionTonic PupilVasoconstrictionEchoencephalographyAmobarbitalAnisocoriaIntracranial Arteriovenous MalformationsCerebrovascular DisordersOculomotor Nerve DiseasesVasodilationCerebral RevascularizationCollateral CirculationMesenteric ArteriesRenal ArteryEclampsiaFemoral ArteryMuscle, Smooth, VascularHemiplegiaIschemic Attack, TransientIntracranial Embolism and ThrombosisDominance, CerebralTreatment OutcomeVasospasm, IntracranialRegional Blood FlowCarotid StenosisStrokeIntracranial ArteriosclerosisIliac ArteryCoronary Artery BypassBlood PressureCarotid Artery DiseasesRadial ArteryRetrospective StudiesFollow-Up StudiesMammary ArteriesBrain Stem InfarctionsSubclavian ArteryTemporal ArteriesImage Processing, Computer-AssistedThalamusTime FactorsCarotid Artery, CommonTemporal LobeVasodilator AgentsConstriction, PathologicCerebral PalsyBrachial ArterySplenic ArteryDogsReference ValuesUmbilical ArteriesCoronary VesselsArtifactsRats, Sprague-DawleyOphthalmic ArteryInfarction, Anterior Cerebral ArteryHepatic ArteryDisease Models, AnimalCerebral HemorrhageEndothelium, VascularNeurologic ExaminationCranial Fossa, PosteriorMesenteric Artery, SuperiorCeliac ArteryVasoconstrictor Agents