Enhancement patterns of intrahepatic cholangiocarcinoma: comparison between contrast-enhanced ultrasound and contrast-enhanced CT.

The aim of this study was to compare the enhancement pattern of intrahepatic cholangiocarcinoma (ICC) on contrast-enhanced ultrasound (CEUS) with that on contrast-enhanced computed tomography (CECT). 40 pathologically proven ICC lesions in 40 patients were evaluated retrospectively with both CEUS and CECT. The enhancement level and pattern in the dynamic phases on both CEUS and CECT were analysed. The diagnostic results of CEUS and CECT before pathological examination were also recorded. During arterial phases, the number of lesions that appeared as (i) peripheral irregular rim-like hyperenhancement, (ii) diffuse heterogeneous hyperenhancement, (iii) diffuse homogeneous hyperenhancement and (iv) diffuse heterogeneous hypoenhancement were 19 (47.5%), 9 (22.5%), 5 (12.5%) and 7 (17.5%), respectively, on CEUS, and 22 (55.0%), 3 (7.5%), 2 (5.0%) and 13 (32.5%), respectively, on CECT (p = 0.125). In the portal phase, the number of lesions showing hyperenhancement and hypoenhancement were 1 (2.5%) and 39 (97.5%), respectively, on CEUS, and 15 (37.5%) and 25 (62.5%) on CECT (p = 0.0001). CEUS made a correct diagnosis in 32 (80.0%) lesions before pathological examination; CECT made a correct diagnosis in 27 (67.5%) lesions (p = 0.18). In conclusion, the enhancement patterns of ICC on CEUS were consistent with those on CECT in the arterial phase, whereas in the portal phase ICC faded out more obviously on CEUS than on CECT. CEUS had the same accuracy as CECT in diagnosing ICCs, and so can be used as a new modality for the characterization of ICC.