Characterization of small liver metastasis with contrast-enhanced ultrasonography

Abstract

Objective To characterize the features of small liver metastasis with contrast-enhanced ultrasound (CEUS). Methods Ninty-four small liver metastasis and 150 small hepatocellular carcinoma (HCC) in Zhongshan Hospital were analyzed on CEUS. Enhancement patterns, the time to enhancement, time to peak, time to isoechogenity and time to hypoechogenity were compared between small liver metastasis and HCC. Results Ninty-four small liver metastasis showed total enhancement and rim-like enhancement at arterial phase, and the incidences were 66.0% (62/94) and 34.0% (32/94), respectively. One hundred and fifty small HCC showed total enhancement and rim-like enhancement at arterial phase, and the incidences were 98.7% (148/150) and 1.3% (2/150), respectively. Small liver metastasis had a significantly higher proportion of rim-like enhancement than that of small HCC (P<0.01). The time to isoechogenity, time to hypoechogenity and time from isoechogenity to hypoechogenity of small liver metastasis were shorter than those of small HCC, which were (28.7±6.3) s, (39.1±16.2) s, (8.1±8.5) s and (35.8±12.5) s, (86.8±45.5) s, (52.5±44.2) s, respectively (t=-8.722, -12.636 and -10.571, all P<0.01). Conclusions Both of the total and rim-like enhancement are common enhancement patterns of small liver metastasis in CEUS. Both of enhancement pattern and washout time are useful in differential diagnosis of small liver metastases and small HCC. CEUS can help to diagnose small liver metastasis. Key words: Ultrasonography; Contrast media; Liver neoplasms; Neoplasms metastasis