Therapeutic response assessment of RFA for HCC: Contrast-enhanced US, CT and MRI

Core tip: Radiofrequency ablation (RFA) therapy is needed to ablate wider range of region than targeted tumor, including surrounding liver tissues that involve micrometastases and microvascular invasion.The local recurrence rate tends to be lower in hepatocellular carcinoma patients with an adequate ablation margin, and thus, it is essential to assess safety margin accurately to reduce local recurrence.From this point of view, we need to focus on the achievement of a sufficient ablation margin as well the lack of tumor vascular enhancement for the assessment of successful RFA.However, inflammatory hyperemia due to RFA which often appears as peripheral rim enhancement, and non-typical imaging features of tumor recurrence sometimes lead to the inappropriate diagnosis.