Imaging-based dynamic liver testing - A computerized simulation

Background/Aims:' The mechanisms for maintaining liver function are complex and currently used liver function tests give limited and often nonspecific and insensitive results. The aim of the study was to demonstrate a dynamic liver test with a tomographic imaging modality as sampling method by means of a computer simulation. Methodology: A virtual three-dimensional liver model, consisting of parench yma and bile ducts, was created using computer aided design/computer aided manufacturing software. An intravenously administered, bile excreted test s ubstance was simulated in the model by awarding changing densities to the p arenchyma and bile ducts in 12 identical sets of the model. Results: Imaging-based density measurements enabled the creation of time-de nsity curves reflecting the transport of the simulated test substance in th e parenchymal mass and bile ducts. By means of quantitative analysis of the curves, parenchymal uptake and excretion and intrahepatic bile flow could be assessed independently. Conclusions: The method enables comparison of function in different liver s egments and may have particular value in investigating diseases that affect the liver in a non-homogenous fashion, for example primary sclerosing chol angitis. Imaging sampling can theoretically be applied with any tomographic imaging technique for which a suitable test substrate exists, including co mputed tomography, magnetic resonance imaging or single photon emission tom ography.