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Hsiao CY, Yang PC, Huang KW. Linear radiofrequency ablation using dual switching-control mode achieves rapid and bloodless liver resection, an experimental research. Int J Hyperthermia 2021; 38:357-362. [PMID: 33641575 DOI: 10.1080/02656736.2021.1892215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
BACKGROUND Radiofrequency (RF)-assisted devices are widely used for hemostasis during liver resection. This study compared the use of dual switching (DS) versus single switching (SS) control modes for RF-based liver resections in a pig model. METHODS The RF-based system comprised a 200-W generator and three electrodes with 4-cm tips arranged in a linear configuration using an adaptor. Eight Lanyu pigs were used to assess ablation outcomes with electrode spacing of 2 or 3 cm, and ablation durations of 1.5, 2 or 3 min. All combinations were tested in DS and SS modes. Procedures were performed on left lateral, caudal and right anterior liver lobes, and after which transections were performed using a scalpel. Blood loss, complete ablation rate and ablation speed were compared. RESULTS DS mode was shown to induce significantly less blood loss than SS mode when the electrode spacing was set at 2 cm and the ablation duration was 2 min or 3 min (p=.010 and .012, respectively). Extended ablation duration and narrow electrode spacing tended to induce less blood loss, regardless of operating mode. Bloodless resection was achieved using DS mode with electrode spacing of 2 cm and ablation duration of 2-3 min. The highest rate of complete ablation (11.3 cm2/min) was achieved using DS mode with electrode spacing of 2 cm and ablation duration of 1.5 min. CONCLUSION RF-based hepatic resection using DS mode is safe and feasible, resulting in less blood loss than SS mode with a higher rate of complete ablation (i.e., superior ablation efficiency).
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Affiliation(s)
- Chih-Yang Hsiao
- College of Medicine, Graduate Institute of Clinical Medicine, National Taiwan University, Taipei, Taiwan.,Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.,Department of Traumatology, National Taiwan University Hospital, Taipei, Taiwan
| | - Po-Chih Yang
- College of Medicine, Graduate Institute of Clinical Medicine, National Taiwan University, Taipei, Taiwan.,Center for Organ Transplantation and Liver Disease Treatment, Fu Jen Catholic University Hospital, New Taipei City, Taiwan
| | - Kai-Wen Huang
- College of Medicine, Graduate Institute of Clinical Medicine, National Taiwan University, Taipei, Taiwan.,Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.,Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan.,Centre of Mini-invasive Interventional Oncology, National Taiwan University Hospital, Taipei, Taiwan
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Comparisons between impedance-based and time-based switching bipolar radiofrequency ablation for the treatment of liver cancer. Comput Biol Med 2021; 134:104488. [PMID: 34020132 DOI: 10.1016/j.compbiomed.2021.104488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 01/19/2023]
Abstract
Switching bipolar radiofrequency ablation (bRFA) is a cancer treatment technique that activates multiple pairs of electrodes alternately based on a predefined criterion. Various criteria can be used to trigger the switch, such as time (ablation duration) and tissue impedance. In a recent study on time-based switching bRFA, it was determined that a shorter switch interval could produce better treatment outcome than when a longer switch interval was used, which reduces tissue charring and roll-off induced cooling. In this study, it was hypothesized that a more efficacious bRFA treatment can be attained by employing impedance-based switching. This is because ablation per pair can be maximized since there will be no interruption to RF energy delivery until roll-off occurs. This was investigated using a two-compartment 3D computational model. Results showed that impedance-based switching bRFA outperformed time-based switching when the switch interval of the latter is 100 s or higher. When compared to the time-based switching with switch interval of 50 s, the impedance-based model is inferior. It remains to be investigated whether the impedance-based protocol is better than the time-based protocol for a switch interval of 50 s due to the inverse relationship between ablation and treatment efficacies. It was suggested that the choice of impedance-based or time-based switching could ultimately be patient-dependent.
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Poch FG, Geyer B, Gemeinhardt O, Klopfleisch R, Niehues SM, Vahldiek JL, Bressem K, Kreis ME, Lehmann KS. Immediate post-interventional contrast-enhanced computed tomography overestimates hepatic microwave ablation - an in vivo animal study. Int J Hyperthermia 2020; 37:463-469. [PMID: 32396401 DOI: 10.1080/02656736.2020.1762936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Objectives: Contrast-enhanced computed tomography (CECT) is used to monitor technical success immediately after hepatic microwave ablation (MWA). However, it remains unclear, if CECT shows the exact extend of the thermal destruction zone, or if tissue changes such as peri-lesionary edema are depicted as well. The objective of this study was to correlate immediate post-interventional CECT with histological and macroscopic findings in hepatic MWA in porcine liver in vivo.Methods: Eleven MWA were performed in porcine liver in vivo with a microwave generator (928 MHz; energy input 24 kJ). CECT was performed post-interventionally. Livers were explanted and ablations were bisected immediately after ablation. Samples were histologically analyzed after vital staining (NADH-diaphorase). Ablation zones were histologically and macroscopically outlined. We correlated histologic findings, macroscopic images and CECT.Results: Three ablation zones were identified in histological and macroscopic findings. Only one ablation zone could be depicted in CECT. Close conformity was observed between histological and macroscopic findings. The ablation zone depicted in CECT overestimated the histological avital central zone and inner red zone (p < = .01). No differences were found between CECT and the histological outer red zone (p > .05).Conclusions: Immediate post-interventional CECT overestimated the clinically relevant zone of complete cell ablation after MWA in porcine liver in vivo. This entails the risk of incomplete tumor ablation and could lead to tumor recurrence.
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Affiliation(s)
- Franz G Poch
- Department of General, Visceral and Vascular Surgery, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Beatrice Geyer
- Department of General, Visceral and Vascular Surgery, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ole Gemeinhardt
- Department of Radiology, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Robert Klopfleisch
- Institute of Veterinary Pathology, Freie Universität Berlin, Berlin, Germany
| | - Stefan M Niehues
- Department of Radiology, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Janis L Vahldiek
- Department of Radiology, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Keno Bressem
- Department of Radiology, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Martin E Kreis
- Department of General, Visceral and Vascular Surgery, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Kai S Lehmann
- Department of General, Visceral and Vascular Surgery, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Berlin, Germany
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Sibinga Mulder BG, Hendriks P, Baetens TR, van Erkel AR, van Rijswijk CSP, van der Meer RW, van de Velde CJH, Vahrmeijer AL, Mieog JSD, Burgmans MC. Quantitative margin assessment of radiofrequency ablation of a solitary colorectal hepatic metastasis using MIRADA RTx on CT scans: a feasibility study. BMC Med Imaging 2019; 19:71. [PMID: 31429708 PMCID: PMC6700773 DOI: 10.1186/s12880-019-0360-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 07/23/2019] [Indexed: 12/12/2022] Open
Abstract
Background Compared to surgery, radiofrequency ablation(RFA) for colorectal liver metastasis(CRLM) is associated with higher local recurrence(LR) rates. A wide margin (at least 5 mm) is generally recommended to prevent LR, but the optimal method to assess ablation margins is yet to be established. The aim of our study was to evaluate the feasibility and reproducibility of CT-CT co-registration, using MIRADA software, in order to assess ablation margins of patients with CRLM. Methods In this retrospective study, pre- and post-ablation contrast-enhanced CT scans of 29 patients, treated with percutaneous RFA for a solitary CRLM, were co-registered. Co-registration was performed by two independent radiologist, based on venous structures in proximity to the tumor. Feasibility of CT-CT co-registration and inter-observer agreement for reproducibility and ablation margins was determined. Furthermore, the minimal ablation margin was compared with the occurrence of LR during follow-up. Results Co-registration was considered feasible in 18 patients (61% male, 63.1(±10.9) year), with a perfect inter-observer agreement for completeness of ablation: κ = 1.0(p < 0.001). And substantial inter-observer agreement for measurement of the minimal margin (≤ 0 mm, 1-5 mm, ≥ 5 mm): κ = 0.723(p-value < 0.001). LR occurred in eight of nine(88.9%) incompletely ablated CRLM and in one of the nine completely ablated CRLM(11.1%). Conclusion Co-registration using MIRADA is reproducible and potentially a valuable tool in defining technical success. Feasibility of co-registration of pre- and post-ablation CT scans is suboptimal if scans are not acquired concordantly. Co-registration may potentially aid in the prediction of LR after percutaneous ablation. Electronic supplementary material The online version of this article (10.1186/s12880-019-0360-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- B G Sibinga Mulder
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands
| | - P Hendriks
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - T R Baetens
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - A R van Erkel
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - C S P van Rijswijk
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - R W van der Meer
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - C J H van de Velde
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands
| | - A L Vahrmeijer
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands
| | - J S D Mieog
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands
| | - M C Burgmans
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
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Jiang AN, Wang S, Yang W, Zhao K, Bai XM, Zhang ZY, Wu W, Chen MH, Yan K. The Role of a Curved Electrode with Controllable Direction in the Radiofrequency Ablation of Liver Tumors Behind Large Vessels. Cardiovasc Intervent Radiol 2019; 42:893-904. [PMID: 30761411 DOI: 10.1007/s00270-019-02182-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 02/05/2019] [Indexed: 01/16/2023]
Abstract
PURPOSE To investigate the role of a novel curved radiofrequency ablation (RFA) electrode with controllable direction in the ablation of tumors behind large hepatic vessels in ex vivo bovine and in vivo canine liver experiments. MATERIALS AND METHODS Approval from the institutional animal care and use committee was obtained. In ex vivo experiments, conventional multi-tines expandable electrodes, conventional monopolar straight electrodes and novel curved electrodes were used in the ablation of the bovine liver (n = 90). The ablated area, parallel axis, vertical axis and shape of different electrodes were compared. Then, 24 beagle dogs (10 months old, female) were used for in vivo experiments. Visual tumor targets deeply located in the portal vein were established, and ultrasound-guided liver ablation was performed with different electrodes. The ablation range, target coverage rate, percentage of normal tissue injury and damage to adjacent vessels were evaluated. The Kruskal-Wallis test and the Chi-squared test were used for statistical analysis. RESULTS For the ex vivo study with a 3-cm electrode, the ablation area of the multi-tines expandable electrode group (7.14 ± 0.16 cm2) was significantly larger than that of the novel curved electrode group (5.01 ± 0.30 cm2, P < 0.001) and the monopolar straight electrode group (5.43 ± 0.15 cm2, P < 0.001). The results obtained with the 4-cm electrode in the three groups were in accordance with those of the 3-cm electrode. In vivo, the normal tissue damage area of the novel curved electrode group was smaller than that of the multi-tines expandable electrode group (1.10 ± 0.18 cm2 vs. 4.00 ± 0.18 cm2, P < 0.001). The target coverage rate of the novel curved electrode group was better than that of the monopolar straight electrode group (100% vs. 80.86 ± 1.68%, P < 0.001). The hematoxylin and eosin (H&E) and TUNEL staining results showed that the ablation necrosis area was adjacent to large vessels, but the vascular wall was not significantly damaged in the novel curved electrode group. CONCLUSION Our preliminary results showed that the novel curved RFA electrode with controllable direction could achieve accurate ablation for tumors behind large hepatic vessels, with a better target coverage rate and less damage to normal tissue, than conventional multi-tines expandable electrodes and monopolar straight electrodes.
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Affiliation(s)
- An-Na Jiang
- Department of Ultrasound, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital and Institute, 52 Fucheng Road, Haidian District, Beijing, 100142, China
| | - Song Wang
- Department of Ultrasound, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital and Institute, 52 Fucheng Road, Haidian District, Beijing, 100142, China
| | - Wei Yang
- Department of Ultrasound, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital and Institute, 52 Fucheng Road, Haidian District, Beijing, 100142, China.
| | - Kun Zhao
- Department of Ultrasound, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital and Institute, 52 Fucheng Road, Haidian District, Beijing, 100142, China
| | - Xiu-Mei Bai
- Department of Ultrasound, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital and Institute, 52 Fucheng Road, Haidian District, Beijing, 100142, China
| | - Zhong-Yi Zhang
- Department of Ultrasound, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital and Institute, 52 Fucheng Road, Haidian District, Beijing, 100142, China
| | - Wei Wu
- Department of Ultrasound, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital and Institute, 52 Fucheng Road, Haidian District, Beijing, 100142, China
| | - Min-Hua Chen
- Department of Ultrasound, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital and Institute, 52 Fucheng Road, Haidian District, Beijing, 100142, China
| | - Kun Yan
- Department of Ultrasound, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital and Institute, 52 Fucheng Road, Haidian District, Beijing, 100142, China
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Chen R, Jiang T, Lu F, Wang K, Kong D. Semi-Automatic Radiofrequency Ablation Planning Based on Constrained Clustering Process for Hepatic Tumors. IEEE Trans Biomed Eng 2017; 65:645-657. [DOI: 10.1109/tbme.2017.2712161] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Yu MH, Lee JY, Jun SR, Kim KW, Kim SH, Han JK, Choi BI. Radiofrequency Ablation with an Internally Cooled Monopolar Directional Electrode: Ex Vivo and in Vivo Experimental Studies in the Liver. Radiology 2015; 278:395-404. [PMID: 26172531 DOI: 10.1148/radiol.2015142269] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE To evaluate the feasibility of using an internally cooled directional electrode (ICDE) to create sufficient directional ablation in the desired area and to investigate whether use of the ICDE reduces thermal injury to the adjacent organs. MATERIALS AND METHODS The animal care and use committee approved this animal study. In ex vivo studies of bovine livers and colons, temperature was measured in both ablation and nonablation directions with the ICDE, temperature at the liver-colon interface and the presence of burns on the colon were evaluated with each ICDE and internally cooled conventional electrode (ICCE), and the ablation area with the use of three ICDEs in the switching multichannel mode was evaluated. In an in vivo study of 10 pigs, 11 ablations were performed by using three ICDEs in the switching multichannel mode. In addition, the difference in thermal injury to the gallbladder and stomach was compared between use of the ICDE and the ICCE. Mann-Whitney test and the Fisher exact test were used for statistical analysis. RESULTS In the ex vivo study, the hepatic temperature in the nonablation direction was lower than 50°C; temperature higher than 47°C was maintained for less than 3 minutes, even 0.5 cm away from the ICDE; and the temperature at the liver-colon interface did not increase above 50°C. In the switching multichannel mode, a fused coagulation zone was created. In the in vivo study, confluent ablation was created in the inner circle of three ICDEs with a mean interelectrode distance of less than 2.6 cm. Use of the ICDE did not create a moderate-to-severe gallbladder wall injury in any of the pigs, but use of the ICCE caused injury in three of the five pigs (P > .05). The ICDE caused moderate-to-severe gastric wall injury at one of eight ablations, and the ICCE caused injury at eight of nine ablations (P < .05). CONCLUSION Use of an ICDE can create a sufficient ablation in the desired direction and can decrease thermal injury to the adjacent organs.
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Affiliation(s)
- Mi Hye Yu
- From the Department of Radiology, KonKuk University Medical Center, Seoul, Korea (M.H.Y.); Department of Radiology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul 110-744, Korea (J.Y.L., S.H.K., J.K.H., B.I.C.); Department of Radiology, Human Medical Imaging and Intervention Center, Seoul, Korea (S.R.J.); and Department of Radiology, Asan Medical Center, Seoul, Korea (K.W.K.)
| | - Jae Young Lee
- From the Department of Radiology, KonKuk University Medical Center, Seoul, Korea (M.H.Y.); Department of Radiology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul 110-744, Korea (J.Y.L., S.H.K., J.K.H., B.I.C.); Department of Radiology, Human Medical Imaging and Intervention Center, Seoul, Korea (S.R.J.); and Department of Radiology, Asan Medical Center, Seoul, Korea (K.W.K.)
| | - Su Ryoung Jun
- From the Department of Radiology, KonKuk University Medical Center, Seoul, Korea (M.H.Y.); Department of Radiology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul 110-744, Korea (J.Y.L., S.H.K., J.K.H., B.I.C.); Department of Radiology, Human Medical Imaging and Intervention Center, Seoul, Korea (S.R.J.); and Department of Radiology, Asan Medical Center, Seoul, Korea (K.W.K.)
| | - Kyung Won Kim
- From the Department of Radiology, KonKuk University Medical Center, Seoul, Korea (M.H.Y.); Department of Radiology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul 110-744, Korea (J.Y.L., S.H.K., J.K.H., B.I.C.); Department of Radiology, Human Medical Imaging and Intervention Center, Seoul, Korea (S.R.J.); and Department of Radiology, Asan Medical Center, Seoul, Korea (K.W.K.)
| | - Se Hyung Kim
- From the Department of Radiology, KonKuk University Medical Center, Seoul, Korea (M.H.Y.); Department of Radiology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul 110-744, Korea (J.Y.L., S.H.K., J.K.H., B.I.C.); Department of Radiology, Human Medical Imaging and Intervention Center, Seoul, Korea (S.R.J.); and Department of Radiology, Asan Medical Center, Seoul, Korea (K.W.K.)
| | - Joon Koo Han
- From the Department of Radiology, KonKuk University Medical Center, Seoul, Korea (M.H.Y.); Department of Radiology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul 110-744, Korea (J.Y.L., S.H.K., J.K.H., B.I.C.); Department of Radiology, Human Medical Imaging and Intervention Center, Seoul, Korea (S.R.J.); and Department of Radiology, Asan Medical Center, Seoul, Korea (K.W.K.)
| | - Byung Ihn Choi
- From the Department of Radiology, KonKuk University Medical Center, Seoul, Korea (M.H.Y.); Department of Radiology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul 110-744, Korea (J.Y.L., S.H.K., J.K.H., B.I.C.); Department of Radiology, Human Medical Imaging and Intervention Center, Seoul, Korea (S.R.J.); and Department of Radiology, Asan Medical Center, Seoul, Korea (K.W.K.)
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Mulier S, Jiang Y, Jamart J, Wang C, Feng Y, Marchal G, Michel L, Ni Y. Bipolar radiofrequency ablation with 2 × 2 electrodes as a building block for matrix radiofrequency ablation:Ex vivoliver experiments and finite element method modelling. Int J Hyperthermia 2015; 31:649-65. [DOI: 10.3109/02656736.2015.1046194] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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Song KD, Lee MW, Park HJ, Cha DI, Kang TW, Lee J, Moon JY, Rhim H. Hepatic radiofrequency ablation: in vivo and ex vivo comparisons of 15-gauge (G) and 17-G internally cooled electrodes. Br J Radiol 2015; 88:20140497. [PMID: 25882688 DOI: 10.1259/bjr.20140497] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE To compare the performance of the 15-G internally cooled electrode with that of the conventional 17-G internally cooled electrode. METHODS A total of 40 (20 for each electrode) and 20 ablation zones (10 for each electrode) were made in extracted bovine livers and in in vivo porcine livers, respectively. Technical parameters, three dimensions [long-axis diameter (Dl), vertical-axis diameter (Dv) and short-axis diameter (Ds)], volume and the circularity (Ds/Dl) of the ablation zone were compared. RESULTS The total delivered energy was higher in the 15-G group than in the 17-G group in both ex vivo and in vivo studies (8.78 ± 1.06 vs 7.70 ± 0.98 kcal, p = 0.033; 11.20 ± 1.13 vs 8.49 ± 0.35 kcal, p = 0.001, respectively). The three dimensions of the ablation zone had a tendency to be larger in the 15-G group than in the 17-G group in both studies. The ablation volume was larger in the 15-G group than in the 17-G group in both ex vivo and in vivo studies (29.61 ± 7.10 vs 23.86 ± 3.82 cm(3), p = 0.015; 10.26 ± 2.28 vs 7.79 ± 1.68 cm(3), p = 0.028, respectively). The circularity of ablation zone was not significantly different in both the studies. CONCLUSION The size of ablation zone was larger in the 15-G internally cooled electrode than in the 17-G electrode in both ex vivo and in vivo studies. ADVANCES IN KNOWLEDGE Radiofrequency ablation of hepatic tumours using 15-G electrode is useful to create larger ablation zones.
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Affiliation(s)
- K D Song
- 1 Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
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Yoon JH, Lee JM, Woo S, Hwang EJ, Hwang I, Choi W, Han JK, Choi BI. Switching bipolar hepatic radiofrequency ablation using internally cooled wet electrodes: comparison with consecutive monopolar and switching monopolar modes. Br J Radiol 2015; 88:20140468. [PMID: 25873479 DOI: 10.1259/bjr.20140468] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
OBJECTIVE To evaluate whether switching bipolar radiofrequency ablation (SB-RFA) using three internally cooled wet (ICW) electrodes can induce coagulations >5 cm in porcine livers with better efficiency than consecutive monopolar (CM) or switching monopolar (SM) modes. METHODS A total of 60 coagulations were made in 15 in vivo porcine livers using three 17-gauge ICW electrodes and a multichannel radiofrequency (RF) generator. RF energy (approximately 200 W) was applied in CM mode (Group A, n = 20) for 24 min, SM mode for 12 min (Group B, n = 20) or switching bipolar (SB) mode for 12 min (Group C, n = 20) in in vivo porcine livers. Thereafter, the delivered RFA energy, as well as the shape and dimension of coagulations were compared among the groups. RESULTS Spherical- or oval-shaped ablations were created in 30% (6/20), 85% (17/20) and 90% (18/20) of coagulations in the CM, SM and SB groups, respectively (p = 0.003). SB-RFA created ablations >5 cm in minimum diameter (Dmin) in 65% (13/20) of porcine livers, whereas SM- or CM-RFA created ablations >5 cm in only 25% (5/20) and 20% (4/20) of porcine livers, respectively (p = 0.03). The mean Dmin of coagulations was significantly larger in Group C than in Groups A and B (5.1 ± 0.9, 3.9 ± 1.2 and 4.4 ± 1.0 cm, respectively, p = 0.002) at a lower delivered RF energy level (76.8 ± 14.3, 120.9 ± 24.5 and 114.2 ± 18.3 kJ, respectively, p < 0.001). CONCLUSION SB-RFA using three ICW electrodes can create coagulations >5 cm in diameter with better efficiency than do SM- or CM-RFA. ADVANCES IN KNOWLEDGE SB-RFA can create large, regular ablation zones with better time-energy efficiency than do CM- or SM-RFA.
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Affiliation(s)
- J H Yoon
- 1 Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea
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Yoon JH, Lee JM, Hwang EJ, Hwang IP, Baek J, Han JK, Choi BI. Monopolar radiofrequency ablation using a dual-switching system and a separable clustered electrode: evaluation of the in vivo efficiency. Korean J Radiol 2014; 15:235-44. [PMID: 24643383 PMCID: PMC3955790 DOI: 10.3348/kjr.2014.15.2.235] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 01/11/2014] [Indexed: 01/18/2023] Open
Abstract
OBJECTIVE To determine the in vivo efficiency of monopolar radiofrequency ablation (RFA) using a dual-switching (DS) system and a separable clustered (SC) electrode to create coagulation in swine liver. MATERIALS AND METHODS Thirty-three ablation zones were created in nine pigs using a DS system and an SC electrode in the switching monopolar mode. The pigs were divided into two groups for two experiments: 1) preliminary experiments (n = 3) to identify the optimal inter-electrode distances (IEDs) for dual-switching monopolar (DSM)-RFA, and 2) main experiments (n = 6) to compare the in vivo efficiency of DSM-RFA with that of a single-switching monopolar (SSM)-RFA. RF energy was alternatively applied to one of the three electrodes (SSM-RFA) or concurrently applied to a pair of electrodes (DSM-RFA) for 12 minutes in in vivo porcine livers. The delivered RFA energy and the shapes and dimensions of the coagulation areas were compared between the two groups. RESULTS No pig died during RFA. The ideal IEDs for creating round or oval coagulation area using the DSM-RFA were 2.0 and 2.5 cm. DSM-RFA allowed more efficient RF energy delivery than SSM-RFA at the given time (23.0 ± 4.0 kcal vs. 16.92 ± 2.0 kcal, respectively; p = 0.0005). DSM-RFA created a significantly larger coagulation volume than SSM-RFA (40.4 ± 16.4 cm(3) vs. 20.8 ± 10.7 cm(3); p < 0.001). Both groups showed similar circularity of the ablation zones (p = 0.29). CONCLUSION Dual-switching monopolar-radiofrequency ablation using an SC electrode is feasible and can create larger ablation zones than SSM-RFA as it allows more RF energy delivery at a given time.
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Affiliation(s)
- Jeong Hee Yoon
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea
| | - Jeong Min Lee
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea. ; Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744, Korea
| | - Eui Jin Hwang
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea
| | - In Pyung Hwang
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea
| | - Jeehyun Baek
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea
| | - Joon Koo Han
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea. ; Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744, Korea
| | - Byung Ihn Choi
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea. ; Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul 110-744, Korea
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Yoon JH, Lee JM, Han JK, Choi BI. Dual switching monopolar radiofrequency ablation using a separable clustered electrode: comparison with consecutive and switching monopolar modes in ex vivo bovine livers. Korean J Radiol 2013; 14:403-11. [PMID: 23690705 PMCID: PMC3655292 DOI: 10.3348/kjr.2013.14.3.403] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 12/26/2012] [Indexed: 01/19/2023] Open
Abstract
Objective To compare the in-vitro efficiency of dual-switching monopolar (DSM) radiofrequency ablation (RFA) using a separable clustered electrode (Octopus® electrodes) with consecutive monopolar (CM) and switching monopolar (SM) RFA techniques to create an ablative zone in the explanted bovine liver. Materials and Methods For DSM-RFA, we used a prototype, three-channel, dual generator RFA Unit and Octopus® electrodes with three, 17 gauge internally cooled electrodes. The RFA Unit allowed simultaneous radiofrequency (RF) energy delivery to two electrodes of the Octopus® electrodes as well as automatic switching among the three electrode pairs according to the impedance changes. RF energy was sequentially applied to one of the three electrodes for 24 minutes (group A; CM mode, n = 10) or alternatively applied for 12 minutes (group B; SM mode, n = 10) or concurrently applied to a pair of electrodes for 12 minutes (group C; DSM mode, n = 10) in explanted bovine livers. Changes in the impedance and current during RFA as well as the dimensions of the thermal ablative zones were compared among the three groups. Results The mean, delivered RF energy amounts in groups A, B, and C were 63.15 ± 8.6 kJ, 72.13 ± 5.4 kJ, and 106.08 ± 13.4 kJ, respectively (p < 0.001). The DSM mode created a significantly larger ablation volume than did the other modes, i.e., 68.1 ± 10.2 cm3 (group A), 92.0 ± 19.9 cm3 (group B), and 115.1 ± 14.0 cm3 (group C) (p < 0.001). The circularity in groups A, B, and C were 0.84 ± 0.06, 0.87 ± 0.04 and 0.90 ± 0.03, respectively (p = 0.03). Conclusion DSM-RFA using Octopus® electrodes can help create large ablative zones within a relatively short time.
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Affiliation(s)
- Jeong-Hee Yoon
- Department of Radiology, Seoul National University College of Medicine, Seoul 110-744, Korea
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13
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Lee ES, Lee JM, Kim KW, Lee IJ, Han JK, Choi BI. Evaluation of the in vivo efficiency and safety of hepatic radiofrequency ablation using a 15-G Octopus® in pig liver. Korean J Radiol 2013; 14:194-201. [PMID: 23482995 PMCID: PMC3590330 DOI: 10.3348/kjr.2013.14.2.194] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Accepted: 09/17/2012] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE To determine in vivo efficacy of radiofrequency ablation (RFA) in porcine liver by using 15-gauge Octopus® (15-G Octopus®) electrodes to create a large coagulation. MATERIALS AND METHODS A total of 18 coagulations were created by using a 180-W generator and 15-G Octopus® electrodes during laparotomy, performed in 14 pigs. Coagulation necrosis was created in the pig livers by the use of one of three RFA protocols: 1) group A, monopolar RFA using a 15-G Octopus® electrode with a 5-mm inter-electrode distance (n = 4); 2) group B, monopolar RFA using a 15-G Octopus® electrode with a 10-mm inter-electrode distance (n = 6); and 3) group C, switching monopolar RFA using two 15-G Octopus® electrodes (n = 8). The energy efficiency, shape, maximum and minimum diameters (Dmx and Dmi), and the volume of the coagulation volume were measured in each group. The Summary statistics were obtained and Mann-Whitney test was were performed. RESULTS The mean ablated volume of each group was 49.23 cm(3) in A, 64.11 cm(3) in B, and 72.35 cm(3) in C. The mean Dmx and Dmi values were 5.68 cm and 4.58 cm in A and 5.97 cm and 4.97 cm in B, respectively. In group C, the mean diameters of Dmx and Dmi were 6.80 cm and 5.11 cm, respectively. The mean ratios of Dmi/Dmx were 1.25, 1.20, and 1.35 in groups A, B, and C, respectively. There was one animal death during the RFA procedure, the cause of which could not be subsequently determined. However, there were no other significant, procedure-related complications during the seven-hour-delayed CT scans. CONCLUSION RFA procedures using 15-G Octopus® electrodes are useful and safe for creating a large ablation in a single electrode model as well as in the multiple electrodes model.
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Affiliation(s)
- Eun Sun Lee
- Department of Radiology, Seoul National University College of Medicine, Seoul 110-744, Korea
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14
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Lee ES, Lee JM, Kim WS, Choi SH, Joo I, Kim M, Yoo DH, Yoo RE, Han JK, Choi BI. Multiple-electrode radiofrequency ablations using Octopus® electrodes in an in vivo porcine liver model. Br J Radiol 2012; 85:e609-15. [PMID: 22422385 DOI: 10.1259/bjr/61619687] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
OBJECTIVES The objective of this study was to determine the in vivo efficacy of radiofrequency ablation (RFA) in porcine liver using Octopus® electrodes for creating a large coagulation compared with RFA using clustered electrodes. METHODS A total of 39 coagulations were created using a 200-W generator and clustered electrodes or Octopus electrodes during laparotomy in 19 pigs. Radiofrequency was applied to the livers using four protocols: (1) Group A-1, monopolar mode using a clustered electrode (n=11); (2) Group A-2, monopolar mode using an Octopus electrode (n=11); (3) Group B-1, consecutive monopolar mode using three, clustered electrodes (n=8); and (4) Group B-2, switching monopolar mode using two Octopus electrodes (n=9). The energy efficiency, shape, diameters (D) and volume (V) of the coagulation volume were compared in each of the two groups. RESULTS The mean maximum D and V of the coagulations in Group A-2 (4.7 cm and 33.1 cm(3), respectively) were significantly larger than those in Group A-1 (4.1 cm and 20.3 cm(3), respectively) (p<0.05). Furthermore, the mean minimum D, maximum D and V of the coagulations in Group B-2 were significantly larger than those in Group B-1, i.e. 5.3 vs 4.0 cm, 6.6 vs 4.9 cm and 66.9 vs 30.2 cm(3), respectively (p<0.05). The energy efficiencies were also significantly higher in Groups A-2 and B-2 than in Groups A-1 and B-1 (p<0.05). CONCLUSION The Octopus electrodes were more efficient for creating a large ablation zone than clustered electrodes, and the efficacy of RFA with Octopus electrodes can be amplified in the switching monopolar mode.
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Affiliation(s)
- E S Lee
- Department of Radiology, Seoul NationalUniversity College of Medicine, Seoul, Republic of Korea
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15
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Multipolar radiofrequency ablation using 4-6 applicators simultaneously: a study in the ex vivo bovine liver. Eur J Radiol 2012; 81:2568-75. [PMID: 22297178 DOI: 10.1016/j.ejrad.2011.10.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 10/21/2011] [Indexed: 02/03/2023]
Abstract
In this study the volume and shape of coagulation zones after multipolar radiofrequency ablation (RFA) with simultaneous use of 4-6 applicators in the ex vivo bovine liver were investigated. The RF-applicators were positioned in 13 different configurations to simulate ablation of large solitary tumors and simultaneous ablation of multiple lesions with 120 kJ of applied energy/session. In total, 110 coagulation zones were induced. Standardized measurements of the volume and shape of the coagulation zones were carried out on magnetic resonance images and statistically analyzed. The coagulation zones induced with solitary applicators and with 2 applicators were imperceptibly small and incomplete, respectively. At 20mm applicator distance, the total ablated volume was significantly larger if all applicators were arranged in a single group compared to placement in 2 distant applicator groups, each consisting of 3 applicators (p=.001). The mean total coagulated volume ranged from immeasurably small (if 6 solitary applicators were applied simultaneously) to 74.7 cc (if 6 applicators at 30 mm distance between neighboring applicators were combined to a single group). Applicator distance, number and positioning array impacted time and shape. The coagulation zones surrounding groups with 4-6 applicators were regularly shaped, homogeneous and completely fused, and the axial diameters were almost constant. In conclusion, multipolar RFA with 4-6 applicators is feasible. The multipolar simultaneous mode should be applied for large and solitary lesions only, small and multiple tumors should be ablated consecutively in standard multipolar mode with up to 3 applicators.
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Lee J, Lee JM, Yoon JH, Lee JY, Kim SH, Lee JE, Han JK, Choi BI. Percutaneous radiofrequency ablation with multiple electrodes for medium-sized hepatocellular carcinomas. Korean J Radiol 2011; 13:34-43. [PMID: 22247634 PMCID: PMC3253401 DOI: 10.3348/kjr.2012.13.1.34] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Accepted: 08/26/2011] [Indexed: 12/29/2022] Open
Abstract
Objective To prospectively evaluate the safety and short-term therapeutic efficacy of switching monopolar radiofrequency ablation (RFA) with multiple electrodes to treat medium-sized (3.1-5.0 cm), hepatocellular carcinomas (HCC). Materials and Methods In this prospective study, 30 patients with single medium-sized HCCs (mean, 3.5 cm; range, 3.1-4.4 cm) were enrolled. The patients were treated under ultrasonographic guidance by percutaneous switching monopolar RFA with a multichannel RF generator and two or three internally cooled electrodes. Contrast-enhanced CT scans were obtained immediately after RFA, and the diameters and volume of the ablation zones were then measured. Follow-up CT scans were performed at the first month after ablation and every three months thereafter. Technical effectiveness, local progression and remote recurrence of HCCs were determined. Results There were no major immediate or periprocedural complications. However, there was one bile duct stricture during the follow-up period. Technical effectiveness was achieved in 29 of 30 patients (97%). The total ablation time of the procedures was 25.4 ± 8.9 minutes. The mean ablation volume was 73.8 ± 56.4 cm3 and the minimum diameter was 4.1 ± 7.3 cm. During the follow-up period (mean, 12.5 months), local tumor progression occurred in three of 29 patients (10%) with technical effectiveness, while new HCCs were detected in six of 29 patients (21%). Conclusion Switching monopolar RFA with multiple electrodes in order to achieve a sufficient ablation volume is safe and efficient. This method also showed relatively successful therapeutic effectiveness on short-term follow up for the treatment of medium-sized HCCs.
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Affiliation(s)
- Jung Lee
- Seoul National University Hospital, Seoul 110-744, Korea
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Yu J, Liang P, Yu X, Liu F, Chen L, Wang Y. A comparison of microwave ablation and bipolar radiofrequency ablation both with an internally cooled probe: results in ex vivo and in vivo porcine livers. Eur J Radiol 2010; 79:124-30. [PMID: 20047812 DOI: 10.1016/j.ejrad.2009.12.009] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 12/03/2009] [Accepted: 12/04/2009] [Indexed: 02/08/2023]
Abstract
PURPOSE The purpose of this study was to compare the effectiveness of microwave (MW) ablation and radiofrequency (RF) ablation using a single internally cooled probe in a hepatic porcine model. MATERIALS AND METHODS In the ex vivo experiment, MW ablations (n=40) were performed with a 2450MHz and 915MHz needle antenna, respectively at 60W, 70W power settings. Bipolar RF ablations (n=20) were performed with a 3-cm (T30) and 4-cm (T40) active tip needle electrodes, respectively at a rated power 30W and 40W according to automatically systematic power setting. In the in vivo experiment, the 2450 MHz and 915 MHz MW ablation both at 60W and T30 bipolar RF ablation at 30 W were performed (n=30). All of the application time were 10 min. Long-axis diameter (Dl), short-axis diameter (Ds), ratio of Ds/Dl, the temperature data 5mm from the needle and the time of temperature 5mm from the needle rising to 54°C were measured. RESULTS Both in ex vivo and in vivo models, Ds and Dl of 915 MHz MW ablations were significantly larger than all the RF ablations (P<0.05); the Ds for all the 2450MHz MW ablations were significantly larger than that of T30 RF ablations (P<0.05). 2450MHz MW and T30 RF ablation tended to produce more elliptical-shaped ablation zone. Tissue temperatures 5mm from the needle were considerably higher with MW ablation, meanwhile MW ablation achieved significantly faster rate of temperature rising to 54°C than RF ablation. For in vivo study after 10 min of ablation, the Ds and Dl of 2450 MHz MW, 915 MHz MW and Bipolar RF were 2.35±0.75, 2.95±0.32, 1.61±0.33 and 3.86±0.81, 5.79±1.03, 3.21±0.51, respectively. Highest tissue temperatures 5mm from the needle were 80.07±12.82°C, 89.07±3.52°C and 65.56±15.31°C and the time of temperature rising to 54°C were respectively 37.50±7.62s, 24.50±4.09s and 57.29±23.24s for three applicators. CONCLUSION MW ablation may have higher potential for complete destruction of liver tumors than RF ablation.
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Affiliation(s)
- Jie Yu
- Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853, China.
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Large-volume multi-tined expandable RF ablation in pig livers: comparison of 2D and volumetric measurements of the ablation zone. Eur Radiol 2009; 20:1073-8. [PMID: 19915850 DOI: 10.1007/s00330-009-1639-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 08/28/2009] [Accepted: 09/05/2009] [Indexed: 01/20/2023]
Abstract
OBJECTIVES To compare two-dimensional (2D) and three-dimensional (3D) computed tomography (CT) measurements of ablation zones (AZs) related to the shaft of two different large-volume monopolar multi-tined expandable electrodes. METHODS Percutaneous radiofrequency (RF) ablation was performed in 12 pigs (81.6 +/- 7.8 kg) using two electrodes (LeVeen 5 cm, Rita XL 5 cm; n = 6 in each group). Contrast-enhanced CT with the electrode shaft in place evaluated the AZ. The largest sphere centred on the electrode shaft within the AZ was calculated (1) based on the 2D axial CT image in the plane of the shaft assuming rotational symmetry of the AZ and (2) using prototype software and the 3D volume data of the AZ measured with CT. RESULTS The mean largest diameter of a sphere centred on the electrode shaft was always smaller using the 3D data of the AZ than using 2D CT measurements assuming rotational symmetry of the AZ (3D vs 2D): LeVeen 18.2 +/- 4.8 mm; 24.5 +/- 3.1 mm; p = 0.001; Rita XL 20.0 +/- 3.7 mm; 28.8 +/- 4.9 mm; p = 0.0002. All AZ showed indentations around the tines. CONCLUSIONS Two-dimensional CT measurements assuming rotational symmetry of the AZ overestimate the largest ablated sphere centred on the electrode shaft compared with 3D CT measurements.
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Radiofrequency ablation of large size liver tumours using novel plan-parallel expandable bipolar electrodes: initial clinical experience. Eur J Radiol 2009; 77:167-71. [PMID: 19616911 DOI: 10.1016/j.ejrad.2009.06.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Accepted: 06/22/2009] [Indexed: 02/06/2023]
Abstract
PURPOSE Although radiofrequency ablation (RFA) is a promising method for local treatment of liver malignancies, with conventional monopolar systems recurrence rates for large size tumours (≥3.5 cm) remain high. The objective of this study was to evaluate the safety, feasibility and local effectiveness of a novel bipolar plan-parallel expandable system for these larger tumours. METHODS AND MATERIALS Eight consecutive patients with either unresectable colorectal liver metastases (CRLM in 6 patients), carcinoid liver metastases (1 patient) and hepatocellular carcinoma (HCC in 1 patient) of ≥3.5 cm were treated with bipolar RFA during laparotomy with ultrasound guidance. Early and late, major and minor complications were recorded. Local success was determined on 3-8 month follow-up CT scans of the upper abdomen. RESULTS Nine CRLM, one carcinoid liver metastases and one HCC (3.5-6.6 cm) were ablated with bipolar RFA. Average ablation time was 16 min (range 6-29 min.). Two patients developed a liver abscess which required re-laparotomy. In both cases bowel surgery during the same session probably caused bacterial spill. There were no mortalities. The patients were released from hospital between 5 and 29 days after the procedure (median 12 days). The 6-12 month follow-up PET-CT scans showed signs for marginal RFA-site tumour recurrence in three patients with CRLM (3/11 lesions). CONCLUSION Preliminary results suggest bipolar RFA to be a reasonably safe, fast and feasible technique which seems to improve local control for large size hepatic tumour ablations.
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Terraz S, Constantin C, Majno PE, Spahr L, Mentha G, Becker CD. Image-guided multipolar radiofrequency ablation of liver tumours: initial clinical results. Eur Radiol 2007; 17:2253-61. [PMID: 17375306 DOI: 10.1007/s00330-007-0626-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 02/03/2007] [Accepted: 02/23/2007] [Indexed: 01/17/2023]
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 < or =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.
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Affiliation(s)
- Sylvain Terraz
- Department of Radiology, Geneva University Hospital, rue Micheli-du-Crest 24, 1211 Geneva 14, Switzerland.
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Lee JM, Han JK, Kim HC, Choi YH, Kim SH, Choi JY, Choi BI. Switching Monopolar Radiofrequency Ablation Technique Using Multiple, Internally Cooled Electrodes and a Multichannel Generator. Invest Radiol 2007; 42:163-71. [PMID: 17287646 DOI: 10.1097/01.rli.0000252495.44818.b3] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE We sought to determine the optimal switching time and interprobe distance for creating a large coagulation zone in the liver by switching monopolar radiofrequency ablation (RFA) technique using a prototype multichannel radiofrequency generator and multiple electrodes. MATERIALS AND METHODS Using 3, 17-gauge, internally cooled electrodes and a prototype multichannel radiofrequency (RF) generator to allow automatic switching of RF energy among 3 electrodes according to their impedance changes, RF energy was applied in a switching monopolar mode to explanted bovine livers or to the livers of 7 dogs. In the ex vivo study, we evaluated the effect of the switching time (5, 15, 30, and 60 seconds) and the interprobe distance (3 cm and 4 cm) on the mean volume of the ablation zone using the switching RFA; we then compared the ablation volume of the switching RFA group (12 minutes) with that of the overlapping RFA group (12 minutes x 3 = 36 minutes). In our preliminary in vivo experiments using 2 dogs, the electrodes were placed in a triangular array (spacing 2 cm, 3 cm, 3.5 cm, or 4 cm) and were activated for 12 minutes or 20 minutes in a monopolar mode (power output 200 W). In our primary experiments using 5 dogs, RFA in a switching mode created 10 coagulation zones at a 2- to 3-cm interprobe distance. The duration of the RFA was 12 minutes. The size and geometry of the coagulation zone also were assessed. RESULTS In this ex vivo study, switching monopolar RFA at a 3-cm interprobe distance and at a 30-second switching time allowed the creation of a large, confluent ablation zone. There was no significant difference in the mean ablation volume between the overlapping (72.9 +/- 12.6(3) cm) and the switching RFA groups (65.7 +/- 12.6 cm(3); P>0.05). In the preliminary in vivo experiments, RFA created spherical coagulations at interprobe distances of 2 cm and 3 cm but at larger distances than 3 cm, RFA created partially confluent coagulation zones. In our principal experiments, switching RFA created areas of well-defined coagulation, ie, at a 2-cm interprobe distance, the volume and short-axis coagulation diameter were 35.5+/- 5.7(3) cm and 4.6 +/- 0.5 cm, respectively, whereas at 3 cm, they were 40.7 +/- 12.8(3) cm and 4.8 +/- 0.8 cm, respectively. The mean values of the circularity (isometric ratio) of the coagulation at the 2- and 3-cm interprobe distances were 0.95 +/- 0.02, and 0.85+/- 0.06, respectively. CONCLUSIONS Our study demonstrated that switching monopolar RFA using the multichannel RF system at a 2- or 3-cm interprobe distance and at a 30-second switching time can create a large, confluent coagulation zone in the liver within a clinically acceptable time frame. We believe that this technology will provide a useful tool for the treatment of large liver tumors.
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Affiliation(s)
- Jeong Min Lee
- Department of Radiology, and Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea
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