Ultrasonography, Doppler, TranscranialUltrasonography, Doppler, ColorBlood Flow VelocityUltrasonography, DopplerCerebrovascular CirculationCerebral ArteriesEchoencephalographyMiddle Cerebral ArteryUltrasonographyTranscranial Magnetic StimulationIntracranial EmbolismUltrasonography, Doppler, PulsedCerebrovascular TraumaAcetazolamideIntracranial Embolism and ThrombosisDoppler EffectIntracranial HypertensionBasilar ArteryAnterior Cerebral ArteryCarotid Artery, InternalCerebral AngiographySensitivity and SpecificityCerebral Arterial DiseasesHyperventilationCerebrovascular DisordersVasomotor SystemArterial Occlusive DiseasesCarbon DioxideUltrasonography, PrenatalProspective StudiesVascular ResistanceReproducibility of ResultsPulsatile FlowDominance, CerebralBrain IschemiaEchocardiography, Doppler, PulsedMagnetic Resonance AngiographyHemodynamicsMagnetic Resonance ImagingContrast MediaValsalva ManeuverEchocardiography, Doppler, ColorRegional Blood FlowCarotid StenosisEvoked Potentials, MotorBrainMonitoring, IntraoperativeCircle of WillisPredictive Value of TestsBlood PressureEmbolism, AirUltrasonography, Doppler, DuplexAngiography, Digital SubtractionImage EnhancementUltrasonicsTomography, X-Ray ComputedOphthalmic ArteryOvarian CystsVertebral ArteryCarotid Artery DiseasesAdnexa UteriEndarterectomy, CarotidUltrasonography, MammaryPregnancyStrokeMotor CortexOvarian DiseasesEmbolism, ParadoxicalFetal DiseasesIschemic Attack, TransientCollateral CirculationPolypsVasospasm, IntracranialVertebrobasilar InsufficiencyObserver VariationImaging, Three-DimensionalLaser-Doppler FlowmetryEndosonographyIntracranial Arteriovenous MalformationsPolysaccharidesSpermatoceleHeart Septal Defects, AtrialHypocapniaConstriction, PathologicForamen Ovale, PatentReference ValuesNeckIntracranial Arterial DiseasesIntracranial PressureSubarachnoid HemorrhageCarotid ArteriesUltrasonography, InterventionalMonitoring, PhysiologicTorsion AbnormalityTime FactorsRetrospective StudiesAngiographyUterusSpermatic Cord TorsionUmbilical Arteries