PET/CT Scans Using the Tracer 11C-Csar, a Bile Acid Analog, to Depict and Visualize Cholestatic Disorders in Patients with Genetic Liver Disorders and Healthy Individuals

Purpose The primary goal is to study liver diseases with defects in bile excretion. Investigators aim to do this using a radioactive tracer that mimics human bile and can be visualized with a PET/CT scanner. This will help us understand where these defects occur and how they might be treated in the future. Background Patients with liver diseases affecting bile excretion are at risk of developing cirrhosis. When bile cannot be excreted normally, it accumulates in the liver, damaging its function. It can also build up in the skin, causing yellowing and itching. Currently, patients are monitored using blood tests that do not always reflect the severity of liver disease. There are a few medications available, but they have limited efficacy. Advanced PET/CT scanning with the radioactive tracer 11C-Csar offers a way to investigate this. 11C-Csar has been developed, tested, and approved for human use at Aarhus University Hospital and has been used in previous patient studies. The study aims to use this method to show how 11C-Csar moves through the liver and bile ducts in both healthy individuals and patients with a genetic liver disease. Investigators aim to: * Observe how defects affect the liver handling of bile acids. * Determine the excretion kinetics of 11C-Csar, including specific rate constants. * Compare standard blood tests with 11C-Csar PET/CT findings to assess how well blood tests reflect actual liver damage. * Visualize potential targets for future interventions. Study Plan The scientific study involves a single examination day at the Department of Nuclear Medicine and PET. Participants will arrive fasting in the morning. An intravenous line will be placed in both arm veins, a catheter in a wrist vessel, and a hepatic vein catheter. The hepatic vein catheter will be inserted by a trained liver specialist using local anesthesia and ultrasound guidance, confirmed by X-ray. The tracer 11C-Csar and the dye indocyanine green (ICG) will be administered through