ESTIMATION OF ORGAN TRANSPORT FUNCTION FROM RECIRCULATING INDICATOR DILUTION CURVES

The transport function of an indicator through an organ allows the cal culation of important physiological parameters, but its estimation, es pecially in the presence of recirculation, can be difficult. In this p aper, we estimate the transport function of H-3-mannitol (an extracell ular tracer of glucose) in the human leg skeletal muscle. To do so, an indicator bolus is administered into the femoral artery and its recir culating dilution curves are nonuniformly sampled in both the femoral artery and the femoral vein. A new deconvolution-based method is used to simultaneously estimate the indicator transport function and the or gan plasma flow. Subsequently, the indicator mean transit time and dis tribution volume are calculated. The reliability of the method is asse ssed by Monte Carlo simulation. The ability to estimate parameters, li ke mean transit time and extracellular distribution volume, is critica l to the study of pathophysiologic states such as diabetes, insulin re sistance, and hypertension. (C) 1998 Biomedical Engineering Society. [ S0090-6964(98)01001-7].