Characterization of primary and recurrent nodules in liver cirrhosis using contrast-enhanced ultrasound: which vascular criteria should be adopted?

PURPOSE: To assess the impact of different vascular patterns at contrast-enhanced ultrasound (CEUS) on the characterization of small liver nodules (10-30 mm) in cirrhosis and to determine whether primary nodules and recurrent nodules (after a previously treated hepatocellular carcinoma) display variations in enhancement pattern.
MATERIALS AND METHODS: A total of 135 cirrhotic patients were evaluated. A diagnosis of hepatocellular carcinoma (HCC) was established according to AASLD Guidelines, based on imaging (computed tomography and/or magnetic resonance) or liver biopsy. All patients underwent CEUS. Different CEUS patterns were evaluated in terms of diagnostic accuracy: HYPER-HYPO: Arterial hyperenhancement followed by washout (hypoechoic appearance compared with surrounding parenchyma) in late phase; HYPER-ISO: Arterial hyperenhancement followed by isoenhancement (isoechoic appearance) in late phase; ISO-ISO: Isoenhancement in all vascular phases.
RESULTS: A total of 155 consecutive primary (n = 90) or recurrent (n = 65) nodules were detected. HCC was diagnosed in 127 nodules (71 primary, 56 recurrent). A characteristic HYPER-HYPO CEUS pattern was revealed in 52/127 (40.9%) HCCs (31 primary, 21 recurrent) giving a positive predictive value (PPV) of 98% (97% primary, 100% recurrent) and an accuracy of 51% (54% primary, 46% recurrent). A HYPER-ISO pattern was noted in 46 HCCs (31 primary, 15 recurrent). Assuming this pattern to also be indicative of HCC, the PPV and accuracy were 94% (93% primary, 97% recurrent) and 77% (84% primary, 68% recurrent), respectively. An ISO-ISO pattern was present in 29 HCCs (9 primary, 20 recurrent) and 22 non-HCCs (14 primary, 8 recurrent).
CONCLUSION: These data confirm that the HYPER-HYPO pattern at CEUS is definitely diagnostic for HCC in cirrhosis and that the HYPER-ISO pattern has a similar PPV, indicating that this pattern is highly suspicious for HCC. The ISO-ISO pattern was found in > 50% of recurrent nodules and indicates a high risk of HCC. © Georg Thieme Verlag KG Stuttgart · New York.