Tomography, X-Ray ComputedColonography, Computed TomographicTomographyTomography, OpticalTomography, Emission-ComputedImaging, Three-DimensionalElectron Microscope TomographyTomography Scanners, X-Ray ComputedTomography, X-RayTomography, Emission-Computed, Single-PhotonRadiographic Image Interpretation, Computer-AssistedImage Processing, Computer-AssistedSensitivity and SpecificityMultidetector Computed TomographyTomography, Spiral ComputedPhantoms, ImagingRadiographic Image EnhancementAngiographyThalliumReproducibility of ResultsThallium RadioisotopesCoronary AngiographyTechnetium Tc 99m SestamibiX-Ray MicrotomographySynchrotronsPredictive Value of TestsTechnology, RadiologicFluorine RadioisotopesContrast MediaRadioisotopesPositron-Emission TomographyOrganotechnetium CompoundsAlgorithmsNitrogen RadioisotopesAortic Aneurysm, AbdominalColonic PolypsCalcinosisParanasal SinusesRadiopharmaceuticalsRetrospective StudiesProspective StudiesBronchographyRadiation DosageCone-Beam Computed TomographyHeartObserver VariationAortographyImage Interpretation, Computer-AssistedImage EnhancementHolographyIohexolRadiography, ThoracicRadiography, AbdominalTechnetiumArtifactsCerebral AngiographyTomography, Optical CoherenceBlood Vessel Prosthesis ImplantationDiagnostic ImagingFollow-Up StudiesMagnetic Resonance ImagingBrainEchocardiography, Four-DimensionalRadionuclide ImagingOximesGallium RadioisotopesChest PainTime FactorsPulmonary EmbolismCryoelectron MicroscopyAorta, AbdominalCoronary DiseaseFeasibility StudiesMediastinal DiseasesCerebrovascular CirculationDipyridamoleCoronary Artery DiseaseHymenolepis nanaBlood Vessel ProsthesisTreatment OutcomeCoronary StenosisFluorodeoxyglucose F18Whole Body ImagingSurgery, Computer-AssistedCystoceleCerebrovascular DisordersModels, AnatomicHematoma, SubduralHematomaOtologic Surgical ProceduresSubtraction TechniqueSeverity of Illness IndexModels, StructuralOxygen RadioisotopesMediastinumGated Blood-Pool ImagingColonoscopyPulmonary EmphysemaCarbon RadioisotopesBrain Diseases