Needle electrode position assessed using three-dimensional ultrasonography and outcome of radiofrequency ablation in hepatocellular carcinoma.

Background/aims: Radiofrequency ablation (RFA) is an established curative therapy for early-stage hepatocellular carcinoma (HCC). We assessed the positions of inserted needle electrodes using three-dimensional ultrasonography (3D-US) and examined the association between the electrode position and outcomes of RFA.

Methodology: Forty-seven patients with 49 HCC nodules treated with a cooled-tip RFA system were enrolled. Immediately after the first insertion of electrodes, 3D volume data were acquired. After RFA completion, the electrode position was assessed using the data.

Results: There were 18 central and 31 marginal pattern nodules. The total number of electrode insertions was significantly greater for the marginal nodules than for the central nodules (p=0.032). In the first session of RFA, 36 HCC nodules (central, n=14; marginal, n=22) were treated with single insertion of electrodes. The ratio of incompletely ablated nodules after the first session was greater for the marginal nodules than for the central nodules (p=0.025).

Conclusions: Our study demonstrated that inserted electrode positions assessed using 3D-US are closely associated with outcomes of RFA and the number of electrode insertions.