Cystic fibrosis (CF) is the most common hereditary disease in Central Europe. The disease is caused by a mutation in the cystic fibrosis transmembrane conductance regulator gene (CFTR). In the liver, fibrotic remodeling can lead to liver cirrhosis in the long term. Early detection of CF hepatopathy is essential to therapeutically slow down the progression of fibrotic remodeling mechanisms. Newborns suffering from CF have a significantly increased risk for the occurrence of meconium ileus and also with advancing age there are symptoms ranging from chronic constipation to Distal Intestinal Obstruction Syndrome (DIOS), due to a reduction of intestinal motility. In this study, the degree of liver fibrosis will now be investigated in adult patients with cystic fibrosis using Multispectral Optoacoustic Imaging (MSOT). In addition, gastrointestinal passage will be studied non-invasively to investigate another affection of the gastrointestinal system.