The Use of Different Imaging Diagnostic Methods in Cholangiocarcinoma.

Abstract

Cholangiocarcinoma (CCA) is a rare but highly lethal malignancy whose timely detection relies heavily on imaging diagnosis. This narrative review examines the clinical utility, characteristic findings, sensitivity, and specificity of the three main diagnostic modalities: ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). US is the initial modality of choice due to its availability and safety. Although limited in sensitivity and specificity, it can reveal indirect signs such as biliary dilatation and hypoechoic masses, guiding further evaluation. CT enhances tumor characterization and assesses extent, vascularity, and infiltration. Typical CT findings include progressive peripheral enhancement and capsular retraction in intrahepatic CCA, or biliary stenosis with upstream dilatation in perihilar and distal forms. Its sensitivity and specificity exceed those of US, but may be inadequate for small lesions. MRI, particularly with magnetic resonance cholangiopancreatography (MRCP), is the most comprehensive modality, offering high sensitivity and specificity and detailed visualization of the biliary tree, tumor extent, and anatomical relationships. Lesions typically appear hypointense on T1-weighted images, hyperintense on T2, and demonstrate delayed contrast enhancement. Together, these techniques complement one another to achieve accurate diagnosis and proper staging, which are essential for guiding treatment. The sequential, protocol-driven integration of these methods improves diagnostic performance, facilitating a more effective approach to CCA.