Quantitative Evaluation of Liver Function with Gd-EOB-DTPA-enhanced MR Imaging

Abstract

The quantitative evaluation of liver function is important, not only for monitoring, but also for the preoperative evaluation of the functional hepatic reserve. The indocyanine green (ICG) clearance has been used as a reliable quantitative liver function test; however, ICG clearance cannot evaluate segmental liver function. Gd-EOB-DTPA is a bolus-injectable paramagnetic contrast media taken up by hepatocytes via organic anion transporting peptide, specifically expressed on cell membrane of hepatocytes; therefore quantitative evaluation of segmental liver function with use of Gd-EOBD-TPA-enhanced MR imaging is feasible. Methods for quantitative evaluation of liver function using Gd-EOB-DTPA-enhanced MR imaging can be divided into the following two major categories : dynamic and static methods. In the dynamic method, the time-intensity curve obtained from dynamic contrast enhanced MR imaging is analyzed using various pharmacokinetic models. The compartment model analysis is a representative method, categorized as a dynamic model-dependent analysis. In the static method, post contrast enhanced images, usually during the hepatobiliary phase, are analyzed using relaxation time or signal intensity of the liver. The static methods are easy to apply in clinical practice. The hepatocellular uptake index (HUI) is a static signal intensity-based method, which is obtained from the signal intensity and volume of the liver and spleen on Gd-EOB-DTPA-enhanced MR images during the hepatobiliary phase. HUI has been accepted as the most reliable predictor of segmental liver function. In this article, pharmacokinetics of Gd-EOB-DTPA is first described using the compartment model. Subsequently, derivation of 2-in-liner-1-uptake-1-out-2-compartment model and HUI are shown as examples of quantitative evaluation of the liver function with the use of Gd-EOB-DTPA-enhanced MR imaging.