Liver Imaging and Hepatobiliary Contrast Media

In the past, great achievements have been made by analysing the drug plasma concentrations to understand their body distribution. At that time, the estimation of liver concentrations was not available. erefore, when conducting pharmacokinetic studies, it was assumed that hepatocyte concentrations approximate plasma concentrations, with the drug equilibration across the sinusoidal membrane being obtained by passive diflusion. With the discovery of hepatocyte transporters that modify the transport rates across hepatocyte membranes, this assumption is no longer valid. e activity of sinusoidal transporters can be much higher than passive diflusion, increasing the hepatocyte concentrations over the plasma concentrations. Moreover, the drug concentrations generated by the hepatocyte uptake clearances are simultaneously modified by eflux clearances from hepatocytes into bile canaliculi and back into sinusoids. us, depending on the relative hepatocyte influx and eflux clearances, drug hepatocyte concentrations can exceed, equal, or be lower than plasma concentrations. Liver imaging can now estimate liver concentrations following the injection of hepatobiliary contrast agents and radiotracers. However, how these concentrations are created is partially unknown. For these reasons, we encouraged the submission of basic, translational, and clinical studies that increase the understanding of liver imaging with hepatobiliary contrast media.