Contrast MediaGadolinium DTPAImage EnhancementTomography, X-Ray ComputedMagnetic Resonance ImagingIopamidolReproducibility of ResultsInjections, IntravenousSensitivity and SpecificityFluorocarbonsIoxaglic AcidWhole-Body CountingUrographyIohexolSubtraction TechniqueRadiopharmaceuticalsPositron-Emission TomographyAdministration, OralEchocardiographyImage Processing, Computer-AssistedRetrospective StudiesProspective StudiesDrug Administration ScheduleUnited States Food and Drug AdministrationDrug Administration RoutesDose-Response Relationship, DrugRats, Sprague-DawleyTime FactorsAdministration, Intranasal