Fig. 1

 A 14-year-old male was diagnosed as intrahepatic recurrent hepatocellular carcinoma (RHCC) at 7 months after initial liver transplantation (LT). Ultrasound-guided radiofrequency ablation (RFA) was performed. (a) A hyperechoic lesion located in Segment 7, with a size of 1.4cmx1.2cmx1.2cm was detected by the grayscale ultrasound. (b, c) On the contrast-enhanced ultrasound (CEUS) images, the targeted lesion displayed homogeneous hyperenhancement in the arterial phase (b) and washout in the portal phase (c). (d) Under the guidance of real-time ultrasound, the No-touch technique was performed by sequentially inserting two electrodes around the periphery of the target lesion and activating them alternatively to perform ablation with a sufficient peri-tumoural margin and avoid direct puncture of the tumor. The second radiofrequency electrode was being inserted, with an inter-electrode distance of 1.1 cm. (e) Hyperechoic zone around the electrode tips appeared and the range extended as the RFA procedure proceeded. (f, g) The next day after RFA, the ablative zone exhibited as heterogeneous hyperechoic on the grayscale ultrasound (f) and displayed no enhancement in all phases on the CEUS images, indicating a complete ablation (g). (h, i) Two months after RFA, the target lesion exhibited non-enhancement on the contrast-enhanced CT (CECT) images