Colonography, Computed TomographicColonic PolypsPolypsColonoscopyNasal PolypsAdenomatous PolypsDiatrizoate MeglumineLaxativesEnemaCatharticsColorectal NeoplasmsRadiographic Image Interpretation, Computer-AssistedTomography, X-Ray ComputedInsufflationBarium SulfateSensitivity and SpecificityIothalamate MeglumineRadiographic Image EnhancementContrast MediaImaging, Three-DimensionalTomography Scanners, X-Ray ComputedColonic DiseasesMass ScreeningColonAdenomaReproducibility of ResultsTomographyFalse Positive ReactionsImage Processing, Computer-AssistedRadiologyPattern Recognition, AutomatedEarly Detection of CancerTomography, OpticalProne PositionOccult BloodIohexolColonic NeoplasmsSigmoidoscopyIncidental FindingsDiagnosis, Computer-AssistedFeasibility StudiesWisconsinProspective StudiesAlgorithmsPatient PreferenceCone-Beam Computed TomographyCost-Benefit AnalysisTomography, Emission-ComputedObserver VariationInfarctionPredictive Value of TestsMagnetic Resonance Imaging