Tracer input for kinetic modelling of liver physiology determined without sampling portal venous blood in pigs

Eur J Nucl Med Mol Imaging. 2011 Feb;38(2):263-70. doi: 10.1007/s00259-010-1620-0. Epub 2010 Sep 30.


Purpose: Quantification of hepatic tracer kinetics by PET requires measurement of tracer input from the hepatic artery (HA) and portal vein (PV). We wished to develop a method for estimating dual tracer input without the necessity to sample PV blood.

Methods: Pigs weighing 40 kg were given bolus doses of C(15)O (CO), 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG), [(11)C]-methylglucose (MG), 2-[(18)F]fluoro-2-deoxy-D-galactose (FDGal) or H(2)(15)O(H(2)O). Tracer concentration 3-min time courses were measured in the femoral artery and PV by blood sampling. Blood flow was measured in the HA and PV using flow-meters. A model for transfer of tracer through the splanchnic circulation was used to estimate values of a tracer-specific model parameter β. Tracer-specific mean values of β were used to estimate tracer concentration time courses in the PV from the measured arterial concentration. A model-derived dual-input was calculated using the mean HA flow fraction (0.25) and validated by comparison of the use of the measured dual-input and a kinetic model with a fixed "true" K(1)(true), i.e. clearance of tracer from blood to liver cells.

Results: The rank order of the means of β was CO < FDG ≈ MG < FDGal < H(2)O, reflecting their different splanchnic mean transit times. Estimated K(1)(est) was not significantly different from "true" K(1)(true).

Conclusion: The hepatic dual tracer input, which is of great importance for the assessment of processes such as transfer across the plasma-hepatocyte membrane or hepatic blood perfusion, can be well approximated in pigs without the necessity to sample PV blood and measure hepatic blood flow; only arterial blood sampling is needed.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Female
  • Hepatic Artery / metabolism
  • Kinetics
  • Liver / blood supply
  • Liver / physiology*
  • Models, Biological*
  • Portal Vein* / metabolism
  • Positron-Emission Tomography
  • Radioactive Tracers*
  • Reproducibility of Results
  • Swine*


  • Radioactive Tracers