胆道系统的病理状况虽然常见，但在临床上很难诊断。胆道成像的挑战包括胆道的解剖变异和动态性质，它们可能随着年龄和干预而变化，模糊正常和异常的界限。胆总管囊肿可能有多种表现，考虑到可能需要手术切除的胆管癌风险，诊断很重要。胆总管结石是胆道扩张的最常见原因，超声和 CT 很难检测到，而 MRI 的敏感性最高。然而，了解 MRI 和 MR 胰胆管造影的成像缺陷对于避免误解至关重要。胆道恶性肿瘤的新概念包括可能发展为胆管癌的导管内乳头状胆管肿瘤。胆管癌分类的新范式对应于该疾病的广泛影像学表现，并对预后具有影响。鉴于包括移植和更积极的手术选择在内的治疗选择不断扩大，对胆管癌进行准确分期势在必行。胆管系统感染包括急性胆管炎或复发性化脓性胆管炎，其特征为梗阻、狭窄和中央胆管扩张。炎症性疾病包括原发性硬化性胆管炎，其特点是狭窄和纤维化，但很难与硬化性胆管炎的继发性病因区分开来，包括最近描述的实体，例如免疫球蛋白 G4 相关的硬化性胆管炎和 COVID-19 继发性硬化性胆管炎。作者描述了各种良性和恶性胆道异常，强调了胆管炎的鉴别特征，提供了一种基于影像学表现模式的解释方法，并讨论了影像学的要点和缺陷，以促进准确诊断。 ©RSNA，2024 本文提供了补充材料。

Pathologic conditions of the biliary system, although common, can be difficult to diagnose clinically. Challenges in biliary imaging include anatomic variants and the dynamic nature of the biliary tract, which can change with age and intervention, blurring the boundaries of normal and abnormal. Choledochal cysts can have numerous appearances and are important to diagnose given the risk of cholangiocarcinoma potentially requiring surgical resection. Choledocholithiasis, the most common cause of biliary dilatation, can be difficult to detect at US and CT, with MRI having the highest sensitivity. However, knowledge of the imaging pitfalls of MRI and MR cholangiopancreatography is crucial to avoid misinterpretation. Newer concepts in biliary tract malignancy include intraductal papillary biliary neoplasms that may develop into cholangiocarcinoma. New paradigms in the classification of cholangiocarcinoma correspond to the wide range of imaging appearances of the disease and have implications for prognosis. Accurately staging cholangiocarcinoma is imperative, given expanding curative options including transplant and more aggressive surgical options. Infections of the biliary tree include acute cholangitis or recurrent pyogenic cholangitis, characterized by obstruction, strictures, and central biliary dilatation. Inflammatory conditions include primary sclerosing cholangitis, which features strictures and fibrosis but can be difficult to differentiate from secondary causes of sclerosing cholangitis, including more recently described entities such as immunoglobulin G4-related sclerosing cholangitis and COVID-19 secondary sclerosing cholangitis. The authors describe a wide variety of benign and malignant biliary tract abnormalities, highlight differentiating features of the cholangitides, provide an approach to interpretation based on the pattern of imaging findings, and discuss pearls and pitfalls of imaging to facilitate accurate diagnosis. ©RSNA, 2024 Supplemental material is available for this article.