Standardized reporting of extrahepatic cholangiocarcinoma.

Cholangiocarcinoma, a primary epithelial malignancy originating in the biliary tree, can be classified based on anatomical location into intrahepatic and extrahepatic cholangiocarcinoma. Extrahepatic cholangiocarcinoma (eCCA) is the more common of the two. CT and MRI play a central role in the diagnosis, staging, and management of eCCA, yet radiological reporting of eCCA often lacks uniformity and completeness which can hamper optimal treatment decision-making. Standardized reporting including standardized terminology and structured reports can address these shortcomings. Standardization produces clear, concise, and accurate terminology to facilitate communication between radiologists, surgeons, oncologists, pathologists, and interventionalists, which can be particularly important in complex cases where treatment hinges on discerning fine anatomical details. Structured report templates organize reporting elements in ordered sections to ensure consistency and completeness when conveying relevant imaging findings. In this manuscript, we aim to provide guidance on eCCA reporting, discussing the relevance of each proposed reporting element and presenting a recommended and structured eCCA reporting template. The proposed structured report, adapted from the template proposed by the Korean Society of Abdominal Radiology, is tailored particularly to North American clinical practice and addresses additional reporting elements such as background liver information and radial dimension.