2-Tissue Compartment Model with Vascular Trapping

This model has been developed by Rizzo et al. [1] for the analysis of [11C]-PBR28 uptake in the human brain. In addition to the compartments in the standard 2-tissue compartment model, a compartment C_vasc was introduced which represents slow binding of the tracer to the endothelium of the vasculature.

Differential Equation of the Mass Balance

with input curve C_p(t).

Operational Model Curve

with the concentration C_B(t) of tracer in whole blood, and the blood volume fraction v_B.

Parameter Fitting

The model includes the 6 fitable parameters vB, K1, k2, k3, k4, Kb. Usually, vB is fixed at a physiologic value of 3-5%. The default initial parameter values are the ones which were used for PBR28.

Reference

1. Rizzo G, Veronese M, Tonietto M, Zanotti-Fregonara P, Turkheimer FE, Bertoldo A. Kinetic modeling without accounting for the vascular component impairs the quantification of [(11)C]PBR28 brain PET data. J Cereb Blood Flow Metab. 2014;34(6):1060-9. DOI