Anemia, Sickle CellSickle Cell TraitHemoglobin, SickleBlood Volume DeterminationErythrocytes, AbnormalAntisickling AgentsBlood VolumeHemoglobin SC DiseaseFetal HemoglobinCerebrovascular CirculationHydroxyureaThalassemiaCoronary OcclusionBalloon OcclusionRetinal Vein OcclusionEcho-Planar ImagingRetinal Artery OcclusionArterial Occlusive Diseasesbeta-ThalassemiaHemoglobinopathiesMagnetic Resonance ImagingErythrocytesJamaicaAcute Chest SyndromeHemoglobinsHemoglobin C DiseaseImage Interpretation, Computer-Assistedalpha-ThalassemiaHemoglobin AHemolysisDental OcclusionLeg UlcerBlood TransfusionErythrocyte DeformabilityExchange Transfusion, Whole BloodHemoglobin CBrainHemoglobins, AbnormalGlobinsHistory, 21st CenturyInfarction, Middle Cerebral ArteryBrain IschemiaVascular DiseasesCerebral InfarctionSplenic InfarctionPainBrain MappingImage EnhancementTime FactorsErythrocyte CountCollateral CirculationOxygenTreatment OutcomeBlood ViscosityReproducibility of ResultsCarotid Artery, InternalErythrocyte AgingErythrocyte MembraneErythrocyte IndicesCerebral AngiographyCerebral ArteriesMesenteric Vascular OcclusionErythrocyte AggregationConstrictionDisease Models, AnimalStrokeOxyhemoglobinsDental Occlusion, CentricRetinal DiseasesHemorheologyReticulocytesTherapeutic OcclusionHomozygoteSensitivity and SpecificityErythrocyte TransfusionHematocritGraft Occlusion, Vasculargamma-Globinsbeta-GlobinsEmbolization, TherapeuticUltrasonography, Doppler, TranscranialBlood Flow VelocityDimethyl AdipimidateAcute DiseaseLutheran Blood-Group SystemCerebral Arterial DiseasesRetrospective StudiesKidney Papillary NecrosisIschemiaNigeriaProspective StudiesDogsSplenic DiseasesConstriction, PathologicFollow-Up StudiesIschemic Attack, TransientHypertension, PulmonaryNeonatal ScreeningInfarctionPriapism