Cholangiocarcinoma is a malignant tumor originating from the bile duct epithelium. Peripheral cholangiocarcinoma arises from the small intra-hepatic bile duct. It consists of multiple nodules or a large lobulated mass without capsule. It usually has hypo-vascularization regarding the arterial vessels and the portal supply also is limited. Arterial hyper-vascularization is less common (Ros et al., 2001). On conventional US the small lesions are hypo- or iso-echoic, whereas the larger lesions are mixed-hyper-hypo-echoic. Color Doppler reveals the absence of intralesional blood flow. During color or power Doppler evaluation it is easy to detect bile duct dilatation and portal venous encasement (Harvey and Albrecht, 2001). Contrast-enhanced ultrasound reveals features close to those of metastasis.
Arterial phase: marginal enhancing;
Portal Vein phase: hypo-, lack of enhancement;
Parenchymal phase: hypo-, lack of enhancement.
Focal liver lesion in segment 4, solid hypoechoic. In arterial phase it is found dishomogenenous enhancement more evidence in portal phase. In early and late parenchymal phase show lack of enhancement.
C.R: proliferative lesion (colangioK)