Published online Apr 21, 2014. doi: 10.3748/wjg.v20.i15.4160
Revised: January 22, 2014
Accepted: February 26, 2014
Published online: April 21, 2014
Processing time: 186 Days and 20.7 Hours
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.