Ultrasonography, Doppler, TranscranialUltrasonography, DopplerBlood Flow VelocityCerebrovascular CirculationUltrasonography, Doppler, ColorUltrasonographyEchoencephalographyCerebral ArteriesMiddle Cerebral ArteryIntracranial Embolism and ThrombosisUltrasonography, Doppler, PulsedIntracranial PressureValsalva ManeuverBrain Hemorrhage, TraumaticTranscranial Magnetic StimulationCerebrovascular DisordersAnemia, Sickle CellHeart Septal Defects, AtrialArterial Occlusive DiseasesDoppler EffectIschemic Attack, TransientProspective StudiesIntracranial EmbolismUltrasonography, PrenatalCerebral AngiographyPulsatile FlowCarbon DioxideStrokeBrain IschemiaSensitivity and SpecificityUltrasonography, Doppler, DuplexBlood PressureBrainRegional Blood FlowEchocardiography, Doppler, PulsedEchocardiography, Doppler, ColorCarotid StenosisEvoked Potentials, MotorReproducibility of ResultsUmbilical ArteriesPredictive Value of TestsCarotid Artery, InternalVascular ResistanceContrast MediaBasilar ArteryTomography, X-Ray ComputedPregnancyCarotid Artery DiseasesMonitoring, IntraoperativeEmbolism, AirOphthalmic ArteryUltrasonicsHemodynamicsPlacental CirculationCircle of WillisScrotumEndarterectomy, CarotidVertebral ArteryPortal VeinFetal DiseasesUltrasonography, InterventionalMagnetic Resonance ImagingSubclavian Steal SyndromeMotor CortexMonitoring, PhysiologicEndosonographyTesticular DiseasesCerebral Arterial DiseasesCarotid ArteriesEmbolism, ParadoxicalReference ValuesVasospasm, IntracranialObserver VariationCollateral CirculationLaser-Doppler FlowmetryArteriesAngiography, Digital SubtractionAcetazolamideTime FactorsConstriction, PathologicTreatment OutcomeHepatic VeinsHypocapniaIntracranial Arterial DiseasesUterusForamen Ovale, PatentPortographyMagnetic Resonance AngiographyRetrospective StudiesSubarachnoid HemorrhageFollow-Up StudiesUltrasonography, MammaryGestational AgeIntracranial HypertensionOvarian CystsFetal Growth RetardationSpermatic CordImaging, Three-DimensionalMetacarpophalangeal JointAcute Disease