Posterior Cerebral ArteryInfarction, Posterior Cerebral ArteryBasilar ArteryCerebral ArteriesCircle of WillisTomography, X-Ray ComputedCerebral AngiographyMiddle Cerebral ArteryInfarction, Middle Cerebral ArteryCerebral InfarctionCerebral Arterial DiseasesHemianopsiaIntracranial AneurysmCerebrovascular CirculationArteriesVertebral ArteryAnterior Cerebral ArteryVertebrobasilar InsufficiencyUltrasonography, Doppler, TranscranialBrain IschemiaMagnetic Resonance ImagingEpidermal CystMagnetic Resonance AngiographyAneurysm, RupturedCarotid Artery, InternalSubarachnoid HemorrhageBrainOccipital LobeEmbolization, TherapeuticBlood Flow VelocityDyslexia, AcquiredArterial Occlusive DiseasesOphthalmoplegic MigraineMoyamoya DiseasePulmonary ArteryCarotid ArteriesAngiography, Digital SubtractionTonic PupilVasoconstrictionEchoencephalographyAmobarbitalAnisocoriaIntracranial Arteriovenous MalformationsCerebrovascular DisordersOculomotor Nerve DiseasesVasodilationCerebral RevascularizationCollateral CirculationMesenteric ArteriesAcute DiseaseRenal 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-AssistedThalamusCarotid Artery, CommonTemporal LobeVasodilator AgentsConstriction, PathologicCerebral PalsyBrachial ArterySplenic ArteryTime FactorsReference ValuesUmbilical ArteriesDogsCoronary VesselsArtifactsOphthalmic ArteryInfarction, Anterior Cerebral ArteryHepatic ArteryRats, Sprague-DawleyDisease Models, AnimalCerebral HemorrhageEndothelium, VascularNeurologic ExaminationCranial Fossa, PosteriorMesenteric Artery, Superior