Value of contrast‐enhanced sonography in the diagnosis of peripheral intrahepatic cholangiocarcinoma

Abstract

To illustrate contrast-enhanced harmonic ultrasonography (CEUS) findings of peripheral intrahepatic cholangiocarcinoma (PICC) and to assess the usefulness of CEUS in the diagnosis of this disease. This study is a retrospective analysis of 46 patients (20 men, 26 women) with PICC who underwent both preoperative CEUS and pathologic examination. Sonographic examinations were performed with sonographic instruments equipped with low mechanical index contrast imaging software. The contrast agent SonoVue was used. The wash-in and wash-out features of the lesions were documented and the enhancement patterns were analyzed by visual inspection of the real-time cine loops. During the hepatic arterial phase of CEUS, the majority of PICC lesions (43/46, 93.5%) showed hypervascularity compared with the liver parenchyma, whereas three lesions (3/46, 6.5%) showed hypovascularity. In the portal phases, all lesions were either isoechoic or hypoechoic, while they were all hypoechoic in the late phase. Of all the hypervascular lesions, 48.8% (21/43) showed diffuse enhancement and 51.2% (22/43) showed rim-like or thick, rim-like enhancement. In 62.8% (27/43) of cases, progressive dendritic and centripetal fill-in of the contrast agent was observed. There were 83.7% (36/43) of hypervascular nodules showing heterogeneous enhancement during peak contrast enhancement of the lesions. CEUS provided clearer visualization of lesion margins than did conventional sonography. CEUS examination yields some specific findings that are useful in the diagnosis of PICC.