Finding Optimal Ablation Parameters for Multipolar Radiofrequency Ablation

Poch, Franz; Rieder, Christian; Ballhausen, Hanne; Knappe, Verena; Ritz, JP; Gemeinhardt, Ole; Kreis, Martin E.; Lehmann, Kai S.

doi:10.1177/1553350617692492

Cited by 6 publications

(5 citation statements)

References 37 publications

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“…These results indicate that there is a cut off in ablation volume in dependence of the applicator distance. A previous ex vivo study demonstrated that higher energy settings are required to induce round and confluent ablation geometries for larger applicator distances 19 . It seems likely, that this factor is even more relevant in in vivo ablations due to the energy loss caused by the liver perfusion (heat sink effect).…”

Section: Discussionmentioning

confidence: 99%

Influence of interapplicator distance on multibipolar radiofrequency ablation during physiological and interrupted liver perfusion in an in vivo porcine model

Poch

Neizert

Geyer

et al. 2020

Sci Rep

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Radiofrequency ablation (RFA) is a curative treatment option for early stage hepatocellular carcinoma (HCC). Vascular inflow occlusion to the liver (Pringle manoeuvre) and multibipolar RFA (mbRFA) represent possibilities to generate large ablations. This study evaluated the impact of different interapplicator distances and a Pringle manoeuvre on ablation area and geometry of mbRFA. 24 mbRFA were planned in porcine livers in vivo. Test series with continuous blood flow had an interapplicator distance of 20 mm and 15 mm, respectively. For a Pringle manoeuvre, interapplicator distance was predefined at 20 mm. After liver dissection, ablation area and geometry were analysed macroscopically and histologically. Confluent and homogenous ablations could be achieved with a Pringle manoeuvre and an interapplicator distance of 15 mm with sustained hepatic blood flow. Ablation geometry was inhomogeneous with an applicator distance of 20 mm with physiological liver perfusion. A Pringle manoeuvre led to a fourfold increase in ablation area in comparison to sustained hepatic blood flow (p < 0.001). Interapplicator distance affects ablation geometry of mbRFA. Strict adherence to the planned applicator distance is advisable under continuous blood flow. The application of a Pringle manoeuvre should be considered when compliance with the interapplicator distance cannot be guaranteed.

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Section: Discussionmentioning

confidence: 99%

Influence of interapplicator distance on multibipolar radiofrequency ablation during physiological and interrupted liver perfusion in an in vivo porcine model

Poch

Neizert

Geyer

et al. 2020

Sci Rep

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“…Antenna to vessel distance, vascular flow rate and vessel diameter were identified as risk factors for incomplete ablation 11 , 13 , 21 . In addition to these previous 2D studies, we investigated the cooling effect three-dimensionally ex vivo using a glass tube as a vascular substitute 22 . Consistent with previous studies, we identified the antenna-vessel spacing as an important factor that considerably affects the cooling effect.…”

Section: Discussionmentioning

confidence: 99%

Three-dimensional assessment of vascular cooling effects on hepatic microwave ablation in a standardized ex vivo model

Neizert

Zibell

et al. 2022

Sci Rep

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The aim of this study was a three-dimensional analysis of vascular cooling effects on microwave ablation (MWA) in an ex vivo porcine model. A glass tube, placed in parallel to the microwave antenna at distances of 2.5, 5.0 and 10.0 mm (A–V distance), simulated a natural liver vessel. Seven flow rates (0, 1, 2, 5, 10, 100, 500 ml/min) were evaluated. Ablations were segmented into 2 mm slices for a 3D-reconstruction. A qualitative and quantitative analysis was performed. 126 experiments were carried out. Cooling effects occurred in all test series with flow rates ≥ 2 ml/min in the ablation periphery. These cooling effects had no impact on the total ablation volume (p > 0.05) but led to changes in ablation shape at A–V distances of 5.0 mm and 10.0 mm. Contrary, at a A–V distance of 2.5 mm only flow rates of ≥ 10 ml/min led to relevant cooling effects in the ablation centre. These cooling effects influenced the ablation shape, whereas the total ablation volume was reduced only at a maximal flow rate of 500 ml/min (p = 0.002). Relevant cooling effects exist in MWA. They mainly depend on the distance of the vessel to the ablation centre.

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“…RFA becomes a widely accepted treatment for primary lung cancer in patients who are not candidates for subsegment resection or lobectomy (36). Compared with radiotherapy and chemotherapy, RFA focuses exclusively on the tumor area without causing any damage to the normal surrounding tissue (37). In addition, compared with surgical treatment, RFA is a minimally-invasive method (38).…”

Section: Discussionmentioning

confidence: 99%

Independent prognostic value of HIF‑1α expression in radiofrequency ablation of lung cancer

et al. 2019

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Radiofrequency ablation (RFA) is widely used in the treatment of lung cancer. Hypoxia-inducible factor-1α (HIF-1α) is a crucial transcription factor regulating oxygen homeostasis that is involved in tumor cell metastasis. The present study investigated the impact of HIF-1α expression and other factors, such as postoperative blood CD4 + /CD8 + ratio, on the prognosis of patients with lung cancer who had received RFA treatment. A total of 80 patients with lung cancer were recruited between January 2011 and October 2016 at The Shenzhen People's Hospital. Lung cancer was confirmed following pathological or histological examination. All patients underwent RFA treatment. Patients were followed up for 6-66 months. HIF-1α expression in lung cancer tissues was assessed by immunohistochemistry. Multivariate survival analysis was performed using Cox proportional hazards model. The results demonstrated that HIF-1α level was low in 36 patients and overexpressed in 44 patients with lung cancer. Kaplan-Meier (KM) curve analysis demonstrated that the overall survival time of patients with high HIF-1α expression was significantly shorter compared with patients with low HIF-1α expression (P<0.05). Furthermore, the results from the KM model and log-rank test revealed that age, Union for International Cancer Control stage, primary or metastatic cancer, chemotherapy, postoperative blood CD4 + /CD8 + ratio, Eastern Cooperative Oncology Group performance status and HIF-1α expression had significant effects on overall survival of patients with lung cancer. The results from Cox analysis demonstrated that high HIF-1α expression, advanced age, clinical staging and chemotherapy were independent risk factors for the prognosis of lung cancer following RFA treatment, and that high HIF-1α expression was associated with the increased risk (5.91-fold) of mortality. In conclusion, the present study demonstrated that HIF-1α expression was increased in lung cancer tissues and was associated with the prognosis of patients with lung cancer who were treated with RFA. These findings suggest that HIF-1α expression may be considered as a marker for evaluating the prognosis of these patients.

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Finding Optimal Ablation Parameters for Multipolar Radiofrequency Ablation

Abstract: The ablation parameters applicator distance and energy input can be chosen in such a way, that minor deviations of the preplanned ablation parameters have no influence on the size of the ablation area.

Cited by 6 publications

References 37 publications

Influence of interapplicator distance on multibipolar radiofrequency ablation during physiological and interrupted liver perfusion in an in vivo porcine model

Influence of interapplicator distance on multibipolar radiofrequency ablation during physiological and interrupted liver perfusion in an in vivo porcine model

Three-dimensional assessment of vascular cooling effects on hepatic microwave ablation in a standardized ex vivo model

Independent prognostic value of HIF‑1α expression in radiofrequency ablation of lung cancer

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