Incorporating a vascular term into a reference region model for the analysis of DCE-MRI data: a simulation study.

A vascular term was incorporated into a reference region (RR) model analysis of DCE-MRI data, and its effect on the accuracy of the model in estimating tissue kinetic parameters in a tissue of interest (TOI) was systematically investigated through computer simulations. Errors in the TOI volume transfer constant (K(trans,TOI)) and TOI extravascular extracellular volume (v(e,TOI)) that result when the fractional plasma volume (v(p)) was included in (1) neither region, (2) TOI only (3) both regions were investigated. For nominal values of tumor kinetic parameters (v(e,TOI) = 0.40 and K(trans,TOI) = 0.25 min(-1)), if the vascular term was included in neither region or the TOI only, K(trans,TOI) error was within 20% for 0.03 < v(p,TOI) < 0.10, and v(e,TOI) error was within 20% for the range of v(p,TOI) studied (0.01-0.10). The effects of temporal resolution were shown to be complex, and in some cases errors increased with increasing temporal resolution.