Abstract: Objective To observe the changes of Contrast-enhanced ultrasound (CEUS) parameters after radiofrequency ablation of recurrent hepatocellular carcinoma (RHCC). Methods A total of 126 RHCC patients admitted to our hospital from January 2017 to January 2021 were selected as the study subjects. All patients received radiofrequency ablation, and CEUS examination was performed 1day and 6 months after treatment, respectively. Patients were divided into a recurrence group (n=11) and a non-recurrence group (n=115) according to whether they relapsed within 6 months. The mean transit time (MTT), time to peak (TTP) and peak intensity (PI) of the two groups were compared. We used the ROC analysis to test the CEUS indicators’ predictive ability in the prognosis of patients who treated by a radiofrequency ablation (RFA) therapy for RHCC. Results MTT of the two groups were (59.18±15.37) s, (43.36±14.48) s, TTP of the two groups were (38.55±12.09) s, (29.51±11.26) s, PI of the two groups were (22.74±7.42) dB, (21.05±6.19) dB, respectively. Compared with non-recurrence group, the recurrence group had longer MTT and TTP (P<0.05) and there was no significant difference in PI between the two groups (P>0.05). According to ROC analysis, the area under curve of MTT and TTP for predicting recurrence within 6 months after RFA treatment of RHCC were 0.968 (95%CI: 0.927-1.000) and 0.871 (95%CI: 0.768-0.974), the sensitivity was 0.818 and 0.727, and the specificity was 0.804 and 0.713, respectively. MTT ≥ 56.706s and TTP ≥ 33.185s were the best truncation values for recurrence within 6 months after RHCC patients received RFA therapy (both P<0.05). Conclusion After RFA, the ultrasound parameters of RHCC patients with different prognosis were different in CEUS examination. CEUS can be used to predict the prognosis of RHCC patients after radiofrequency ablation with high sensitivity and specificity.

Key words: Hepatocellular carcinoma, Recurrence, Radiofrequency ablation, Ultrasonic imaging