Tracer kinetic modeling approaches for the quantification of hepatic function with technetium-99m DISIDA and scintigraphy.

Serial scintigraphic images following injection of [99mTc]iminodiacetic acid compounds such as [99mTc]diisopropyl-iminodiacetic acid (DISIDA) provide qualitative information about liver function. We have investigated approaches for quantitatively describing liver function in terms of the kinetics of DISIDA extraction and excretion by the liver. Several compartmental model configurations were evaluated. A three-compartment model (blood, hepatic parenchyma, intrahepatic bile) was found to fit the data best and was used in conjunction with dynamic image data to obtain estimates of rate constants for liver extraction and excretion of DISIDA, and mean residence time (MRT) of DISIDA in the liver. A noncompartmental approach based on a parametric deconvolution technique was also used to estimate the noncompartmental mean residence time (MRTnc). To assess limitations of the noncompartmental approach, computer simulations were performed using the three-compartment model to generate time-activity curves followed by analysis of these curves by the noncompartmental method. The effect of plasma total bilirubin level on DISIDA uptake and MRT was also investigated. These techniques are readily adaptable to standard nuclear medicine computing facilities, and could be used in the clinical setting to numerically describe serial DISIDA studies (especially in liver transplant patients) efficiently and noninvasively.