History, 20th CenturyHistory, 21st CenturyBlood VolumePlasma VolumeStroke VolumeLung Volume MeasurementsErythrocyte VolumeBlood Volume DeterminationMagnetic Resonance ImagingForced Expiratory VolumeImaging, Three-DimensionalOrgan SizeResidual VolumeImage Processing, Computer-AssistedReproducibility of ResultsCell SizeTime FactorsBrainTomography, X-Ray Computed