Intrahepatic peripheral cholangiocarcinoma (IPCC): comparison between perfusion ultrasound and CT imaging.

Purpose: This study was done to compare the perfusion patterns of intrahepatic peripheral cholangiocarcinoma (IPCC) on contrast-enhanced ultrasound (CEUS) and dynamic computed tomography (CT).
Materials and Methods: We retrospectively reviewed 23 histologically proven cases of IPCC. All lesions were studied by CEUS with sulfur hexafluoride-filled microbubbles coated with a phospholipid capsule, and by dynamic CT. Contrast-enhancement patterns were evaluated in the arterial phase (CEUS 10-20 s after the injection; CT 25-30 s after the injection) and in the delayed phase (CEUS 120 s after the injection; CT>2-3 min after the injection).
Results: Lesions were single in 18/23 cases (78%), single with nearby satellite lesions in 1/23 (4%) cases and multifocal with distant secondary lesions in 4/23 (17%) cases. Lesion diameter was 2-5 cm in 7/23 cases (30%), 5-7 cm in 13/23 cases (57%) and >7 cm in 3/23 (13%) cases. On CEUS, lesions were hypervascular in 16/23 cases (70%). On delayed-phase CEUS, 22/23 lesions (96%) were markedly hypoechoic. CT showed that the lesions were hypovascular in the arterial phase in 15/23 cases (66%) and hypervascular in 7/23 (30%) cases; one lesion (1/23; 4%) was isovascular. On delayed-phase CT, lesions were hyperdense in 17/23 cases (74%), hypodense in 5/23 (22%) cases and isodense in 1/23 (43%) cases.
Conclusions: Enhancement discrepancy between delayed-phase CEUS (hypoechogenicity) and CT (hyperdensity) is common semiological findings in the study of IPCC.