Anterior Cerebral ArteryColicInfarction, Anterior Cerebral ArteryCerebral ArteriesMesenteric ArteriesCerebral AngiographyIntracranial AneurysmMesenteric Artery, SuperiorMiddle Cerebral ArteryCircle of WillisRenal ColicCerebral Arterial DiseasesArteriesInfarction, Middle Cerebral ArteryCerebral InfarctionAneurysm, RupturedSubarachnoid HemorrhageCerebrovascular CirculationTomography, X-Ray ComputedBasilar ArteryCarotid Artery, InternalMesenteric Artery, InferiorUltrasonography, Doppler, TranscranialCarotid ArteriesMagnetic Resonance AngiographyBrain IschemiaBlood Flow VelocityVertebral ArteryCerebral RevascularizationIntracranial Embolism and ThrombosisEchoencephalographyArterial Occlusive DiseasesVasospasm, IntracranialIschemic Attack, TransientAngiography, Digital SubtractionPulmonary ArteryEmbolization, TherapeuticBrainNeurosurgical ProceduresIntracranial Arteriovenous MalformationsBrain Hemorrhage, TraumaticRenal ArteryPosterior Cerebral ArteryDominance, CerebralCraniotomyAneurysm, DissectingFemoral ArteryAkinetic MutismMagnetic Resonance ImagingIntracranial ArteriosclerosisCeliac ArteryCerebrovascular DisordersUltrasonography, DopplerMoyamoya DiseaseCerebral HemorrhageTreatment OutcomeVasoconstrictionRegional Blood FlowMesenteric Vascular OcclusionSurgical InstrumentsMuscle, Smooth, VascularVasodilationSuperior Mesenteric Artery SyndromeCarotid Artery DiseasesIliac ArteryCarotid StenosisStrokeCollateral CirculationCoronary Artery BypassHematomaRadial ArteryUltrasonographyTime FactorsSplenic ArteryRetrospective StudiesVasodilator AgentsFrontal LobeMammary ArteriesVasoconstrictor AgentsEndothelium, VascularRats, Sprague-DawleySubclavian ArteryHepatic ArteryTemporal ArteriesFecal ImpactionFollow-Up StudiesRats, WistarBiological FactorsBlood PressureCarotid Artery, CommonSplanchnic CirculationHorse DiseasesPostoperative ComplicationsCerebral PalsyBrachial ArteryUmbilical ArteriesCoronary VesselsInfant, NewbornNorepinephrineOphthalmic Artery