This work investigates the usage of contrast agents in ultrasound for biliary tract diseases. Building on the prior work “Verifikation von Cholelithiasis mittels Ultraschallbildgebung“ a relation between cholelithiasis and other diseases of the biliary tract, as well as work-relevant competencies in terms of radiation therapists should be established. In addition, an explanation of malignant and benign mutations of the biliary tract is given and therefore the aid of contrast agents is examined. For this purpose, the setup and functional principle of these agents are specified beforehand. The prepared review should demonstrate, among which mutations of the biliary tract the application of contrast agents are indicated and whether these mutations can be differentiated better than without. Furthermore, advantages of contrast agents are presented. This work is based on comprehensive literature research and hereof in- and exclusion criteria are defined. A comparison between studies is established and findings are displayed in graphic and tabular form.