Block diagram indicating the rate constants, K1–k4, between the 3 compartments of the FDG kinetic model. The left compartment represents the vascular space for FDG, Ca. The middle compartment represents the extravascular space for FDG, Ce, and the right compartment represents the cellular space for phosphorylated FDG-6-Phosphate (FDG-6-P), Cm. The second and third compartments add up-to form the myocardial tissue compartment, CT.