Aim: To evaluate the efficiency of intraoperative contrast enhanced ultrasound (Io-CEUS) for assessment of radiofrequency ablation (RFA) during liver tumor surgery.
Material and methods: Retrospective analysis was performed on a total number of 18 patients out of over 500 patients who underwent combined liver tumor surgery and RFA of 27 hepatic tumors between 02/2011 and 12/2016. Io-CEUS was performed by bolus injections of up to 10 ml sulphur hexaflourid microbubbles for diagnostic purposes. To guide the RFA up to 20 ml microbubbles were applied to monitor the procedure and assess the ablation status finally. A fully avascular area or absence of any residual vascularization intratumorally was considered technical success. These findings were correlated to findings of follow-up imaging results (CEUS, MRI, CT) at least 1 up to 40 months (mean 11 months) after surgery.
Results: 13 male and 5 female patients aged between 45-77 years (mean 59.2±17.1 years) with 26 malignant and one most probable benign hepatic lesion were treated with intraoperative RFA. Io-CEUS detected 23 preoperatively unknown liver lesions leading to a change in therapy in 13/18 cases (72,2%). All 27 treated lesions showed an avascular area immediately after RFA. According to follow-up imaging results (1 month - 3 years after surgery, mean follow-up time 11 months), 2/18 patients had local recurrences, 8 patients had distant intrahepatic recurrences or extrahepatic recurrence, 8 patients remained tumor-free. Thereby, a success rate of CEUS guided RFA of 89% could be obtained concerning the targeted liver lesions.
Conclusion: Modern intraoperative ultrasound using B-mode and Io-CEUS is a valuable tool for optimization of diagnostic and therapeutic intraoperative liver procedures and ablative therapies.
Keywords: CEUS; intraoperative ultrasound; liver surgery; radiofrequency ablation.