Ultrasonography, DopplerUltrasonography, Doppler, ColorUltrasonographyUltrasonography, Doppler, PulsedUltrasonography, Doppler, TranscranialBlood Flow VelocityUltrasonography, PrenatalDoppler EffectPulsatile FlowUltrasonography, Doppler, DuplexSensitivity and SpecificityCerebrovascular CirculationProspective StudiesUmbilical ArteriesRegional Blood FlowPregnancyScrotumEchoencephalographyPortal VeinEndosonographyUltrasonography, InterventionalPlacental CirculationTesticular DiseasesFetal DiseasesEchocardiography, Doppler, PulsedReproducibility of ResultsContrast MediaVascular ResistanceTomography, X-Ray ComputedCerebral ArteriesMiddle Cerebral ArteryEchocardiography, Doppler, ColorPredictive Value of TestsPortographyUltrasonography, MammaryHepatic VeinsArteriesSpermatic CordUterusOvarian CystsOphthalmic ArteryMetacarpophalangeal JointArterial Occlusive DiseasesHepatic ArteryCarotid Artery DiseasesIntracranial Embolism and ThrombosisGestational AgeObserver VariationRenal ArteryImaging, Three-DimensionalSubclavian Steal SyndromeRetrospective StudiesAngiographyValsalva ManeuverFetal Growth RetardationLiver CirculationCerebrovascular DisordersSulfur HexafluorideSynovitisUltrasonicsAbdomenIntracranial PressureCarotid ArteriesPregnancy Trimester, SecondCarotid Artery, InternalVaginaMesenteric Artery, SuperiorHemodynamicsHemangioma, CapillaryBrain Hemorrhage, TraumaticConstriction, PathologicFetal HeartReference ValuesTreatment OutcomeMagnetic Resonance ImagingVenous ThrombosisFollow-Up StudiesVertebral ArteryInfant, NewbornThoracic CavityHypertension, PortalPregnancy Trimester, FirstCarotid StenosisLaser-Doppler FlowmetryArteriovenous MalformationsROC CurveVena Cava, InferiorVeinsFetusTrophoblastic NeoplasmsAngiography, Digital SubtractionBlood PressureOvarySeverity of Illness IndexCerebral AngiographyTime FactorsAnemia, Sickle CellSplenic ArteryUrographyLeg