Imaging of intrahepatic progression of hepatocellular carcinoma post transarterial chemoembolization. A long-term, prospective evaluation of contrast-enhanced ultrasonography (CEUS)

Aim: To assess the diagnostic efficacy of contrast- enhanced ultrasonography (CEUS) in the context of intrahepatic progression (IHP) of hepatocellular carcinoma (HCC) after transarterial chemoembolization (TACE). Material and methods: Sixty HCC patients were prospectively included in the study. They were treated with transarterial chemoembolization (TACE) with doxorubicin-eluting microspheres (231 sessions). Imaging follow-up was performed 1 month after each session and at 3-6 month intervals after the last session of TACE and included CEUS and contrast- enhanced magnetic resonance (MR) imaging (reference modality). The diagnosis of IHP was based on mRECIST criteria and the respective findings of MR and CEUS were recorded, categorized and correlated. Results: A total of 441 CEUS studies were compared with the corresponding MR studies. During a follow-up period of 5-82 months (mean: 22 months), MR diagnosed 51 cases of IHP in 34/60 (56.6%) patients. CEUS correctly diagnosed 12/14 (85.7%) cases of IHP of target tumors, 2/5 (40%) cases of IHP of non-target tumors, 13/18 (72.2%) cases of distal and 6/9 (66.6%) cases of proximal new lesions, and 5/5 (100%) cases of major vessel involvement. On a per-lesion basis, CEUS was significantly inferior to MR in the detection of new lesions (p=0.002). No false positive CEUS diagnoses of IHP were observed. 54% of the diagnostic failures of CEUS were considered clinically significant. Conclusion: In the long term evaluation of HCC post TACE, CEUS appears to have limitations in the detection of IHP, which are more prominent in the case of new lesions and of progressive non-target tumors.