Regional Blood FlowMicrospheresBlood Flow VelocityTomography, Emission-Computed, Single-PhotonCerebrovascular CirculationCardiac OutputHemodynamicsBlood CirculationCoronary CirculationVascular ResistanceDogsSplanchnic CirculationOrganotechnetium CompoundsBlood PressureScandiumRenal CirculationLiver CirculationXenon RadioisotopesPulmonary CirculationLaser-Doppler FlowmetryHeart RateTomography, Emission-ComputedAnesthesiaOxygenRadioisotopesBrainTechnetium Tc 99m ExametazimeBlood Gas AnalysisNitrogen RadioisotopesNafronylOxygen ConsumptionVentilation-Perfusion RatioOxygen RadioisotopesOximesPhentolamineRadiopharmaceuticalsKidneyHeartSwineHindlimbCarbon DioxideMicrocirculationModels, CardiovascularImmersionVasoconstrictionPartial PressureBlood VolumeVasodilator AgentsTime FactorsIschemiaIliac ArteryRenal ArteryVasodilationPulmonary Gas ExchangeSupine PositionAnesthesia, InhalationMyocardiumNG-Nitroarginine Methyl EsterCollateral CirculationTechnetium Tc 99m SestamibiIsofluraneLegInfusions, ParenteralMagnetic Resonance ImagingNitric OxideMesenteric ArteriesCatsFlow CytometryRats, Sprague-DawleySympathetic Nervous SystemPropranololThallium RadioisotopesForearmMuscle, SkeletalSheepNorepinephrineRats, WistarInjections, IntravenousCoronary VesselsReference ValuesIodine RadioisotopesRats, Inbred StrainsDose-Response Relationship, DrugNitric Oxide SynthasePulsatile FlowRabbitsDisease Models, AnimalImage Processing, Computer-AssistedMyocardial ContractionLungCoronary DiseaseArteriesGated Blood-Pool ImagingIofetamineMyocardial InfarctionTechnetiumSensitivity and SpecificityCapillariesGamma CamerasBlood Donors