Purpose: To retrospectively evaluate the dynamic enhancement pattern of contrast-enhanced ultrasound (CEUS) in intrahepatic cholangiocarcinoma (ICC) of varying sizes and hepatic backgrounds.
Materials and methods: CEUS was performed in 98 pathologically confirmed ICCs (n = 39 < 30 mm, n = 59 > 30 mm; n = 45 with cirrhosis and n = 53 with normal liver). The dynamic enhancement pattern of CEUS was retrospectively analyzed.
Results: In the arterial phase, heterogeneous hyper-enhancement was more frequent in ICCs with cirrhosis (21/45, 46.7% vs. 11/53, 20.8% in ICCs with normal liver, p = 0.009), while peripheral hyper-enhancement and hypo-enhancement were more common in ICCs with normal liver (14/53, 26.4%; 11/53, 20.8% vs. 2/45, 4.4%; 2/45, 4.4% in ICCs with cirrhosis, p = 0.005 and 0.033, respectively). There were no significant differences between portal and delayed phases. In ICCs < 30 mm, homogeneous hyper-enhancement was more frequently identified (27/39, 69.2% vs. 10/59, 16.9% in ICCs > 30 mm, p < 0.001), whereas in ICCs > 30 mm, heterogeneous, and peripheral hyper-enhancement were more commonly observed (26/59, 44.1% vs. 6/39, 15.4% in ICCs < 30 mm, p = 0.004, and 14/59, 23.7% vs. 2/39, 5.1% in ICCs < 30 mm, p = 0.023, respectively). The washout pattern in portal and delayed phases were not significantly different in ICCs with different sizes. 60.7% (17/28) ICCs < 30 mm and 85.2% (23/27) ICCs > 30 mm with cirrhosis, together with 66.7% (14/21) ICCs < 30 mm with normal liver displayed intense contrast agent uptake (homogeneous or heterogeneous hyper-enhancement) in arterial phase followed by washout in portal and delayed phase, which was much higher than that in ICCs > 30 mm with normal liver (34.4%, 11/32, p < 0.001, <0.001 and =0.027, respectively).
Conclusion: The CEUS dynamic enhancement pattern of ICC varies with size and hepatic background. The enhancement pattern is indistinguishable from hepatocellular carcinoma on CEUS in most ICCs with cirrhosis and in most ICCs < 30 mm with normal liver.