Image-guided multipolar radiofrequency ablation of liver tumours: initial clinical results

Abstract

The local effectiveness and clinical usefulness of multipolar radiofrequency (RF) ablation of liver tumours was evaluated. Sixty-eight image-guided RF sessions were performed using a multipolar device with bipolar electrodes in 53 patients. There were 45 hepatocellular carcinomas (HCC) and 42 metastases with a diameter ≤3 cm (n=55), 3.1-5 cm (n=29) and >5 cm (n=3); 26 nodules were within 5 mm from large vessels. Local effectiveness and complications were evaluated after RF procedures. Mean follow-up was 17±10 months. Recurrence and survival rates were analysed by the Kaplan-Meier method. The primary and secondary technical effectiveness rate was 82% and 95%, respectively. The major and minor complication rate was 2.9%, respectively. The local tumour progression at 1-and 2-years was 5% and 9% for HCC nodules and 17% and 31% for metastases, respectively; four of 26 nodules (15%) close to vessels showed local progression. The survival at 1 year and 2 years was 97% and 90% for HCC and 84% and 68% for metastases, respectively. Multipolar RF technique creates ablation zones of adequate size and tailored shape and is effective to treat most liver tumours, including those close to major hepatic vessels.

Wide-bore 1.5 Tesla MR imagers for guidance and monitoring of radiofrequency ablation of renal cell carcinoma: initial experience on feasibility

“…The application of multipolar RF systems offers several advantages as compared to conventional systems using cluster or multitined electrodes [15][16]: First, multipolar RF systems provide larger coagulation diameters without repositioning; therefore, a lower risk of needle tract seeding due to applicator repositioning may be expected. Second, RCC tumors are often dense, thus hampering puncture using a needle with large diameter such as a multitined electrode, or using a cluster electrode.…”

Radiofrequency ablation of hepatocellular carcinoma: Mono or multipolar?

“…19 Thus with multipolar devices, it becomes conceivable to treat tumors larger than 3 cm completely, with sufficient safety margins, via a single application of RF. 13,20 Using multipolar RF, Seror et al achieved complete ablation of 81% (22 of 27) of their HCCs larger than 49 mm (median: 57 mm) without technical failure. 21 Moreover, in the multipolar technique, as the energy is focused on the target zone, a more homogeneous energy deposition and a larger ablation zone should be possible.…”

Radiofrequency ablation of small liver malignancies under magnetic resonance guidance: progress in targeting and preliminary observations with temperature monitoring

“…For 12 lesions, a single bipolar electrode was positioned at the centre of the tumour. Two electrodes were placed at the periphery of the target tumour when its long-axis diameter exceeded 2 cm (n=2) or when lying in contact with a large hepatic vessel (n=2) [19]. The final position of the RF electrodes with regard to the index tumour was verified on the 3D T1-weighted VIBE sequence.…”

“…MR-compatible RF ablation system RF ablation was performed with a 470-kHz multipolar RF generator (Celon AG, Teltow, Germany) coupled with one or two internally cooled MR-compatible electrodes (active tip length, 3 cm; shaft length, 15 cm) [18,19]. The algorithm of energy deposition was based on the manufacturer's guidelines for power settings and included the resistance-controlled automatic power (RCAP) mode.…”