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Nolte T, Vaidya N, Baragona M, Elevelt A, Lavezzo V, Maessen R, Schulz V, Veroy K. Study of flow effects on temperature-controlled radiofrequency ablation using phantom experiments and forward simulations. Med Phys 2021; 48:4754-4768. [PMID: 34320224 DOI: 10.1002/mp.15138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 05/24/2021] [Accepted: 07/16/2021] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Blood flow is known to add variability to hepatic radiofrequency ablation (RFA) treatment outcomes. However, few studies exist on its impact on temperature-controlled RFA. Hence, we investigate large-scale blood flow effects on temperature-controlled RFA in flow channel experiments and numerical simulations. METHODS Ablation zones were induced in tissue-mimicking, thermochromic phantoms with a single flow channel, using an RF generator with temperature-controlled power delivery and a monopolar needle electrode. Channels were generated by molding the phantom around a removable rod. Channel radius and saline flow rate were varied to study the impact of flow on (i) the ablated cross-sectional area, (ii) the delivered generator power, and (iii) the occurrence of directional effects on the thermal lesion. Finite volume simulations reproducing the experimental geometry, flow conditions, and generator power input were conducted and compared to the experimental ablation outcomes. RESULTS Vessels of different channel radii r affected the ablation outcome in different ways. For r = 0.275 mm, the ablated area decreased with increasing flow rate while the energy input was hardly affected. For r = 0.9 mm and r = 2.3 mm, the energy input increased toward larger flow rates; for these radii, the ablated area decreased and increased toward larger flow rates, respectively, while still being reduced overall as compared to the reference experiment without flow. Directional effects, that is, local shrinking of the lesion upstream of the needle and an extension thereof downstream, were observed only for the smallest radius. The simulations qualitatively confirmed these observations. As compared to performing the simulations without flow, including flow effects in the simulations reduced the mean absolute error between experimental and simulated ablated areas from 0.23 to 0.12. CONCLUSION While the temperature control mechanism did not detect the heat sink effect in the case of the smallest channel radius, it counteracted the heat sink effect in the case of the larger channel radii with an increased energy input; this explains the increase in ablated area toward high flow rates (for r = 2.3 mm). The experiments in a simple phantom setup, thus, contribute to a good understanding of the phenomenon and are suitable for model validation.
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Affiliation(s)
- Teresa Nolte
- Department of Physics of Molecular Imaging systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
| | - Nikhil Vaidya
- Faculty of Civil Engineering, RWTH Aachen University, Aachen, Germany
| | | | | | | | | | - Volkmar Schulz
- Department of Physics of Molecular Imaging systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany.,Hyperion Hybrid Imaging Systems GmbH, Aachen, Germany.,Physics Institute III B, RWTH Aachen University, Aachen, Germany.,Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany
| | - Karen Veroy
- Center for Analysis, Scientific Computing, and Applications, Eindhoven University of Technology, Eindhoven, The Netherlands
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Singh M, Singh T, Soni S. Pre-operative Assessment of Ablation Margins for Variable Blood Perfusion Metrics in a Magnetic Resonance Imaging Based Complex Breast Tumour Anatomy: Simulation Paradigms in Thermal Therapies. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 198:105781. [PMID: 33065492 DOI: 10.1016/j.cmpb.2020.105781] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/28/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND OBJECTIVES Image-guided medical interventions facilitates precise visualization at treatment site. The conformal prediction for sparing healthy tissue fringes precisely in the vicinity of irregular tumour anatomy remains clinically challenging. Pre-clinical image-based computational modelling is imperative as it helps in enhancement of treatment quality, augmenting clinical-decision making, while planning, targeting, controlling, monitoring and assessing treatment response with an effective risk assessment before the onset of treatment in clinical settings. In this study, the influence of heat deposition rate (SAR), exposure duration, and variable blood perfusion metrics for a patient-specific breast tumour is quantified considering the tumour margins thereby suggesting need of geometrically accurate models. METHODS A three-dimensional realistic model mimicking dimensions of a female breast, comprising ~1.7 cm irregular tumour, was generated from patient specific two-dimensional DICOM format MRI images through image segmentation tools MIMICS 19.0® and 3-Matic 11.0® which is finally exported to COMSOL Multiphysics 5.2® as a volumetric mesh for finite element analysis. The Pennes bioheat transfer model and Arrhenius thermal damage model of cell-death are integrated to simulate a coupled biophysics problem. A comparative blood perfusion analysis is done to evaluate the response of tumour during heating considering thermal damage extent, including the tumour margins while sparing critical adjoining healthy tissues. RESULTS The evaluated thermal damage zones for 1 mm, 2 mm and 3 mm fringe heating region (beyond tumour boundary) reveals 0.09%, 0.21% and 0.34% thermal damage to the healthy tissue (which is <1%) and thus successful necrosis of the tumour. The iterative computational experiments suggests treatment margins < 5 mm are sufficient enough as heating beyond 3 mm fringe layer leads to higher damage surrounding the tumour approximately 1.5 times the tumour volume. Further, the heat-dosage requirements are 22% more for highly perfused tumour as compared to moderately perfused tumour with an approximate double time to ablate the whole tumour volume. CONCLUSIONS Depending on the blood perfusion characteristics of a tumour, it is a trade-off between heat-dosage (SAR) and exposure/treatment duration to get desired thermal damage including the irregular tumour boundaries while taking into account, the margin of healthy tissue. The suggested patient-specific integrated multiphysics-model based on MRI-Images may be implemented for pre-treatment planning based on the tumour blood perfusion to evaluate the thermal ablation zone dimensions clinically and thereby avoiding the damage of off-target tissues. Thus, risks involving underestimation or overestimation of thermal coagulation zones may be minimised while preserving the surrounding normal breast parenchyma.
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Affiliation(s)
- Manpreet Singh
- Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA; Biomedical Instrumentation Division, CSIR-Central Scientific Instruments Organisation, Chandigarh, India; Department of Mechanical Engineering, Thapar Institute of Engineering and Technology University, Patiala, Punjab, India.
| | - Tulika Singh
- Department of Radio-diagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Sanjeev Soni
- Biomedical Instrumentation Division, CSIR-Central Scientific Instruments Organisation, Chandigarh, India
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Vahldiek JL, Erxleben C, Bressem KK, Gemeinhardt O, Poch F, Hiebl B, Lehmann KS, Hamm B, Niehues SM. Multipolar RFA of the liver: Influence of intrahepatic vessels on ablation zones and appropriateness of CECT in detecting ablation dimensions - Results of an in-vivo porcine liver model. Clin Hemorheol Microcirc 2019; 70:467-476. [DOI: 10.3233/ch-189313] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Janis L. Vahldiek
- Department of Radiology, Charité-University Medicine Berlin, Berlin, Germany
| | - Christoph Erxleben
- Department of Radiology, Charité-University Medicine Berlin, Berlin, Germany
| | - Keno Kyrill Bressem
- Department of Radiology, Charité-University Medicine Berlin, Berlin, Germany
| | - Ole Gemeinhardt
- Department of Surgery, Charité-University Medicine Berlin, Berlin, Germany
| | - Franz Poch
- Department of Surgery, Charité-University Medicine Berlin, Berlin, Germany
| | - Bernhard Hiebl
- Institute for Animal Hygiene, Animal Welfare and Farm Animal Behaviour, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Kai S. Lehmann
- Department of Surgery, Charité-University Medicine Berlin, Berlin, Germany
| | - B. Hamm
- Department of Radiology, Charité-University Medicine Berlin, Berlin, Germany
| | - Stefan M. Niehues
- Department of Radiology, Charité-University Medicine Berlin, Berlin, Germany
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Poch FGM, Rieder C, Ballhausen H, Knappe V, Ritz JP, Gemeinhardt O, Kreis ME, Lehmann KS. Finding Optimal Ablation Parameters for Multipolar Radiofrequency Ablation. Surg Innov 2017; 24:205-213. [PMID: 28193132 DOI: 10.1177/1553350617692492] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE Radiofrequency ablation (RFA) for primary liver tumors and liver metastases is restricted by a limited ablation size. Multipolar RFA is a technical advancement of RFA, which is able to achieve larger ablations. The aim of this ex vivo study was to determine optimal ablation parameters for multipolar RFA depending on applicator distance and energy input. METHODS RFA was carried out ex vivo in porcine livers with three internally cooled, bipolar applicators in multipolar ablation mode. Three different applicator distances were used and five different energy inputs were examined. Ablation zones were sliced along the cross-sectional area at the largest ablation diameter, orthogonally to the applicators. These slices were digitally measured and analyzed. RESULTS Sixty RFA were carried out. A limited growth of ablation area was seen in all test series. This increase was dependent on ablation time, but not on applicator distance. A steady state between energy input and energy loss was not observed. A saturation of the minimum radius of the ablation zone was reached. Differences in ablation radius between the three test series were seen for lowest and highest energy input ( P < .05). No differences were seen for medium amounts of energy ( P > .05). CONCLUSIONS 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.
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Affiliation(s)
| | - Christian Rieder
- 2 Fraunhofer MEVIS, Institute for Medical Image Computing, Bremen, Germany
| | - Hanne Ballhausen
- 2 Fraunhofer MEVIS, Institute for Medical Image Computing, Bremen, Germany
| | - Verena Knappe
- 3 Laser- und Medizin-Technologie GmbH, Berlin, Germany
| | - Jörg Peter Ritz
- 4 Klinik für Allgemein- und Viszeralchirurgie, HELIOS Kliniken Schwerin, Schwerin, Germany
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Tsui PH, Wang CY, Zhou Z, Wan YL. Monitoring Radiofrequency Ablation Using Ultrasound Envelope Statistics and Shear Wave Elastography in the Periablation Period: An In Vitro Feasibility Study. PLoS One 2016; 11:e0162488. [PMID: 27603012 PMCID: PMC5014384 DOI: 10.1371/journal.pone.0162488] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 08/02/2016] [Indexed: 01/03/2023] Open
Abstract
Radiofrequency ablation (RFA) is a minimally invasive method for treating tumors. Shear wave elastography (SWE) has been widely applied in evaluating tissue stiffness and final ablation size after RFA. However, the usefulness of periablation SWE imaging in assessing RFA remains unclear. Therefore, this study investigated the correlation between periablation SWE imaging and final ablation size. An in vitro porcine liver model was used for experimental validation (n = 36). During RFA with a power of 50 W, SWE images were collected using a clinical ultrasound system. To evaluate the effects of tissue temperature and gas bubbles during RFA, changes in the ablation temperature were recorded, and image echo patterns were measured using B-mode and ultrasound statistical parametric images. After RFA, the gross pathology of each tissue sample was compared with the region of change in the corresponding periablation SWE image. The experimental results showed that the tissue temperature at the ablation site varied between 70°C and 100°C. Hyperechoic regions and changes were observed in the echo amplitude distribution induced by gas bubbles. Under this condition, the confounding effects (including the temperature increase, tissue stiffness increase, and presence of gas bubbles) resulted in artifacts in the periablation SWE images, and the corresponding region correlated with the estimated final ablation size obtained from the gross pathology (r = 0.8). The findings confirm the feasibility of using periablation SWE imaging in assessing RFA.
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Affiliation(s)
- Po-Hsiang Tsui
- Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Medical Imaging Research Center, Institute for Radiological Research, Chang Gung University and Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
- Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
- * E-mail: (PHT); (YLW)
| | - Chiao-Yin Wang
- Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Zhuhuang Zhou
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Yung-Liang Wan
- Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Medical Imaging Research Center, Institute for Radiological Research, Chang Gung University and Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
- Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
- * E-mail: (PHT); (YLW)
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Lehmann KS, Poch FGM, Rieder C, Schenk A, Stroux A, Frericks BB, Gemeinhardt O, Holmer C, Kreis ME, Ritz JP, Zurbuchen U. Minimal vascular flows cause strong heat sink effects in hepatic radiofrequency ablation ex vivo. JOURNAL OF HEPATO-BILIARY-PANCREATIC SCIENCES 2016; 23:508-16. [PMID: 27338856 DOI: 10.1002/jhbp.370] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/21/2016] [Indexed: 01/03/2023]
Abstract
BACKGROUND The present paper aims to assess the lower threshold of vascular flow rate on the heat sink effect in bipolar radiofrequency ablation (RFA) ex vivo. METHODS Glass tubes (vessels) of 3.4 mm inner diameter were introduced in parallel to bipolar RFA applicators into porcine liver ex vivo. Vessels were perfused with flow rates of 0 to 1,500 ml/min. RFA (30 W power, 15 kJ energy input) was carried out at room temperature and 37°C. Heat sink effects were assessed in RFA cross sections by the decrease in ablation radius, area and by a high-resolution sector planimetry. RESULTS Flow rates of 1 ml/min already caused a significant cooling effect (P ≤ 0.001). The heat sink effect reached a maximum at 10 ml/min (18.4 mm/s) and remained stable for flow rates up to 1,500 ml/min. CONCLUSIONS Minimal vascular flows of ≥1 ml/min cause a significant heat sink effect in hepatic RFA ex vivo. A lower limit for volumetric flow rate was not found. The maximum of the heat sink effect was reached at a flow rate of 10 ml/min and remained stable for flow rates up to 1,500 ml/min. Hepatic inflow occlusion should be considered in RFA close to hepatic vessels.
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Affiliation(s)
- Kai S Lehmann
- Department of General and Vascular Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Franz G M Poch
- Department of General and Vascular Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Christian Rieder
- Fraunhofer Institute for Medical Image Computing MEVIS, Bremen, Germany
| | - Andrea Schenk
- Fraunhofer Institute for Medical Image Computing MEVIS, Bremen, Germany
| | - Andrea Stroux
- Institute for Biometry and Clinical Epidemiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Bernd B Frericks
- Department of Diagnostic and Interventional Radiology, DRK Kliniken Berlin Westend, Berlin, Germany
| | - Ole Gemeinhardt
- Department of General and Vascular Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Christoph Holmer
- Department of General and Vascular Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Martin E Kreis
- Department of General and Vascular Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jörg P Ritz
- Department of General and Visceral Surgery, HELIOS Kliniken Schwerin, Schwerin, Germany
| | - Urte Zurbuchen
- Department of General and Vascular Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany
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Abstract
PURPOSE To demonstrate and quantify the heat sink effect in hepatic microwave ablation (MWA) in a standardized ex vivo model, and to analyze the influence of vessel distance and blood flow on lesion volume and shape. MATERIALS AND METHODS 108 ex vivo MWA procedures were performed in freshly harvested pig livers. Antennas were inserted parallel to non-perfused and perfused (700,1400 ml/min) glass tubes (diameter 5mm) at different distances (10, 15, 20mm). Ablation zones (radius, area) were analyzed and compared (Kruskal-Wallis Test, Dunn's multiple comparison Test). Temperature changes adjacent to the tubes were measured throughout the ablation cycle. RESULTS Maximum temperature decreased significantly with increasing flow and distance (p<0.05). Compared to non-perfused tubes, ablation zones were significantly deformed by perfused tubes within 15 mm distance to the antenna (p<0.05). At a flow rate of 700 ml/min ablation zone radius was reduced to 37.2% and 80.1% at 10 and 15 mm tube distance, respectively; ablation zone area was reduced to 50.5% and 89.7%, respectively. CONCLUSION Significant changes of ablation zones were demonstrated in a pig liver model. Considerable heat sink effect was observed within a diameter of 15 mm around simulated vessels, dependent on flow rate. This has to be taken into account when ablating liver lesions close to vessels.
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"Edgeboost": A Novel Technique to Extend the Ablation Zone Lateral to a Two-Probe Bipolar Radiofrequency Device. Cardiovasc Intervent Radiol 2015; 39:97-105. [PMID: 26155781 DOI: 10.1007/s00270-015-1168-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 06/23/2015] [Indexed: 01/17/2023]
Abstract
BACKGROUND The dual-electrode bipolar-RFA (B-RFA) is increasingly used to ablate large liver tumours (3-7 cm). However, the challenging aspect of B-RFA is the placement of the two electrodes around the tumour. Realignment often requires the electrodes to be extracted and reinserted. AIM The aim of this study is to examine "Edgeboost", a novel technique to increase the lateral ablation dimension without requiring any realignment of the electrodes. METHODS AND MATERIALS An egg-white model and an ex vivo calf liver model were used compare the standard bipolar mode ablation to Edgeboost-1 (reaching full impedance in bipolar mode initially, then cycling in unipolar mode between left and right probes) and Edgeboost-2 (similar to Edgeboost-1 but not reaching full impedance initially in bipolar mode in order to minimize charring and, thus, to increase total ablation time). RESULTS A significantly larger outer lateral ablation dimension to the probe was achieved with Edgeboost-1 compared to the standard method in the liver model (1.14 cm, SD: 0.16 vs. 0.44 cm, SD: 0.24, p = 0.04). Edgeboost-2 achieved the largest outer lateral ablation dimension of 1.75 cm (SD: 0.35). A similar association was seen in the egg model. Edgeboost-2 almost doubled the mass ablated with standard bipolar alone (mass ratio: 1:1.94 in egg white and 1:1.84 in liver). CONCLUSION This study demonstrates that the novel "Edgeboost" technique can increase the outer lateral ablation dimension without requiring the two inserted electrodes to be reinserted. This would be beneficial for interventionists who use the dual B-RFA.
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Staged resection of bilobar colorectal liver metastases: surgical strategies. Langenbecks Arch Surg 2015; 400:633-40. [PMID: 26049744 DOI: 10.1007/s00423-015-1310-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 05/28/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND Radical resection is the treatment of choice for colorectal liver metastases (CLM). Unfortunately, only about 20 % of patients present with initially resectable disease, in most cases due to bilobar disease. In the last two decades, major achievements have been made to extend surgical indications to patients with bilobar CLM, such as two-stage hepatectomy with or without portal vein occlusion and associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). PURPOSE The purpose of this review article was to summarize current surgical approaches and their safety and efficacy for patients with initially unresectable bilobar CLM. CONCLUSION In selected patients, two-stage hepatectomy and ALPPS are efficient and safe to convert unresectable to resectable CLM. Further studies are required to evaluate long-term outcome of these procedures.
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Clinical efficacy of bipolar radiofrequency ablation of small renal masses. World J Urol 2014; 33:1535-40. [DOI: 10.1007/s00345-014-1422-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 10/16/2014] [Indexed: 10/24/2022] Open
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Reissfelder C, Rahbari NN, Bejarano LU, Schmidt T, Kortes N, Kauczor HU, Büchler MW, Weitz J, Koch M. Comparison of various surgical approaches for extensive bilateral colorectal liver metastases. Langenbecks Arch Surg 2014; 399:481-91. [PMID: 24615142 DOI: 10.1007/s00423-014-1177-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 02/18/2014] [Indexed: 12/12/2022]
Abstract
PURPOSE Tailored operative strategies have been proposed for patients with bilobar colorectal liver metastases (CLM). The aim of the study was to evaluate the long-term outcome, safety and efficacy, including cancer-specific survival, morbidity, and mortality, of three different surgical strategies for extensive bilateral CLM. METHODS This is a retrospective study of a prospective database of 356 consecutive patients, who underwent hepatic resection due to CLM between January 2003 and January 2009. Fifty-nine patients underwent three different therapeutic approaches: 22 patients with portal vein embolization (PVE) + staged resections, 11 patients with staged resections solely, and 26 patients with an extensive liver resection and simultaneous or subsequent radiofrequency ablation (RFA). RESULTS The three groups were comparable regarding their general patient characteristics. The overall morbidity and mortality rates were 27.1 and 1.7 %, respectively. There were no significant differences in morbidity, mortality, or survival between the three groups. The median survival of all patients was 48 months, with a recurrence-free survival of 30 months. CONCLUSIONS The clearance of bilobar CLM can be achieved by various strategies, all of them providing an acceptable mortality rate and survival for the patients. Therefore, patients with bilobar liver metastases should receive a procedure tailored for their individual extent of disease.
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Affiliation(s)
- Christoph Reissfelder
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany,
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Furse A, Miller BJ, McCann C, Kachura JR, Jewett MA, Sherar MD. Radiofrequency coil for the creation of large ablations: ex vivo and in vivo testing. J Vasc Interv Radiol 2013; 23:1522-8. [PMID: 23101925 DOI: 10.1016/j.jvir.2012.08.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 07/31/2012] [Accepted: 08/13/2012] [Indexed: 01/12/2023] Open
Abstract
PURPOSE Various radiofrequency (RF) ablation electrode designs have been developed to increase ablation volume. Multiple heating cycles and electrode positions are often required, thereby increasing treatment time. The objective of this study was to evaluate the performance of a high-frequency monopolar induction coil designed to produce large thermal lesions (>3 cm) with a single electrode insertion in a treatment time of less than 10 minutes. MATERIALS AND METHODS A monopolar nitinol interstitial coil operated at 27.12 MHz and 200 W was evaluated. Ex vivo performance was tested in excised bovine liver (n = 22). In vivo testing (n = 10) was conducted in livers of seven Yorkshire pigs. Visual inspection, contrast-enhanced computed tomography (CT), and pathologic evaluation of ablation zones were performed. RESULTS Average ablation volumes in ex vivo and in vivo tests were 60.5 cm(3) ± 14.1 (5.9 × 4.4 × 4.4 cm) and 57.1cm(3) ± 13.8 (6.1 × 4.5 × 4.1cm), with average treatment times of 9.0 minutes ± 3.0 and 8.4 minutes ± 2.7, respectively. Contrast-enhanced CT ablation volume measurements corresponded with findings of gross inspection. Pathologic analysis showed morphologic and enzymatic changes suggestive of tissue death within the ablation zones. CONCLUSIONS The RF ablation coil device successfully produced large, uniform ablation volumes in ex vivo and in vivo settings in treatment times of less than 10 minutes. Ex vivo and in vivo lesion sizes were not significantly different (P = .53), suggesting that the heating efficiency of this higher-frequency coil device may help to minimize the heat-sink effect of perfusion.
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Affiliation(s)
- Alex Furse
- Division of Biophysics and Bioimaging, Ontario Cancer Institute, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada.
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Pandeya GD, Greuter MJW, Schmidt B, Flohr T, Oudkerk M. Assessment of thermal sensitivity of CT during heating of liver: an ex vivo study. Br J Radiol 2012; 85:e661-5. [PMID: 22919016 DOI: 10.1259/bjr/23942179] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVES The purpose of this study was to assess the thermal sensitivity of CT during heating of ex-vivo animal liver. METHODS Pig liver was indirectly heated from 20 to 90 °C by passage of hot air through a plastic tube. The temperature in the heated liver was measured using calibrated thermocouples. In addition, image acquisition was performed with a multislice CT scanner before and during heating of the liver sample. The reconstructed CT images were then analysed to assess the change of CT number as a function of temperature. RESULTS During heating, a decrease in CT numbers was observed as a hypodense area on the CT images. In addition, the hypodense area extended outward from the heat source during heating. The analysis showed a linear decrease of CT number as a function of temperature. From this relationship, we derived a thermal sensitivity of CT for pig liver tissue of -0.54±0.03 HU °C(-1) with an r(2) value of 0.91. CONCLUSIONS The assessment of the thermal sensitivity of CT in ex-vivo pig liver tissue showed a linear dependency on temperature ≤90 °C. This result may be beneficial for the application of isotherms or thermal maps in CT images of liver tissue.
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Affiliation(s)
- G D Pandeya
- Department of Radiology, UMC Groningen, University of Groningen, Groningen, The Netherlands.
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Image-based 3D modeling and validation of radiofrequency interstitial tumor ablation using a tissue-mimicking breast phantom. Int J Comput Assist Radiol Surg 2012; 7:941-8. [PMID: 22688380 DOI: 10.1007/s11548-012-0769-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 05/29/2012] [Indexed: 01/18/2023]
Abstract
PURPOSE Minimally invasive treatment of solid cancers, especially in the breast and liver, remains clinically challenging, despite a variety of treatment modalities, including radiofrequency ablation (RFA), microwave ablation or high-intensity focused ultrasound. Each treatment modality has advantages and disadvantages, but all are limited by placement of a probe or US beam in the target tissue for tumor ablation and monitoring. The placement is difficult when the tumor is surrounded by large blood vessels or organs. Patient-specific image-based 3D modeling for thermal ablation simulation was developed to optimize treatment protocols that improve treatment efficacy. METHODS A tissue-mimicking breast gel phantom was used to develop an image-based 3D computer-aided design (CAD) model for the evaluation of a planned RF ablation. First, the tissue-mimicking gel was cast in a breast mold to create a 3D breast phantom, which contained a simulated solid tumor. Second, the phantom was imaged in a medical MRI scanner using a standard breast imaging MR sequence. Third, the MR images were converted into a 3D CAD model using commercial software (ScanIP, Simpleware), which was input into another commercial package (COMSOL Multiphysics) for RFA simulation and treatment planning using a finite element method (FEM). For validation of the model, the breast phantom was experimentally ablated using a commercial (RITA) RFA electrode and a bipolar needle with an electrosurgical generator (DRE ASG-300). The RFA results obtained by pre-treatment simulation were compared with actual experimental ablation. RESULTS A 3D CAD model, created from MR images of the complex breast phantom, was successfully integrated with an RFA electrode to perform FEM ablation simulation. The ablation volumes achieved both in the FEM simulation and the experimental test were equivalent, indicating that patient-specific models can be implemented for pre-treatment planning of solid tumor ablation. CONCLUSION A tissue-mimicking breast gel phantom and its MR images were used to perform FEM 3D modeling and validation by experimental thermal ablation of the tumor. Similar patient-specific models can be created from preoperative images and used to perform finite element analysis to plan radiofrequency ablation. Clinically, the method can be implemented for pre-treatment planning to predict the effect of an individual's tissue environment on the ablation process, and this may improve the therapeutic efficacy.
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Sommer C, Kortes N, Mogler C, Bellemann N, Holzschuh M, Arnegger F, Nickel F, Gehrig T, Zelzer S, Meinzer H, Longerich T, Stampfl U, Kauczor H, Radeleff B. Super-micro-bland particle embolization combined with RF-ablation: Angiographic, macroscopic and microscopic features in porcine kidneys. Eur J Radiol 2012; 81:1165-72. [DOI: 10.1016/j.ejrad.2011.03.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Accepted: 03/04/2011] [Indexed: 12/22/2022]
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Sommer CM, Koch V, Pap B, Bellemann N, Holzschuh M, Gehrig T, Shevchenko M, Arnegger FU, Nickel F, Mogler C, Zelzer S, Meinzer HP, Stampfl U, Kauczor HU, Radeleff BA. Effect of Tissue Perfusion on Microwave Ablation: Experimental in Vivo Study in Porcine Kidneys. J Vasc Interv Radiol 2011; 22:1751-7. [DOI: 10.1016/j.jvir.2011.07.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 07/16/2011] [Accepted: 07/22/2011] [Indexed: 12/11/2022] Open
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Feasibility of Noninvasive Temperature Assessment During Radiofrequency Liver Ablation on Computed Tomography. J Comput Assist Tomogr 2011; 35:356-60. [DOI: 10.1097/rct.0b013e318217121d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ritz JP, Lehmann KS, Schumann T, Knappe V, Zurbuchen U, Buhr HJ, Holmer C. Effectiveness of various thermal ablation techniques for the treatment of nodular thyroid disease--comparison of laser-induced thermotherapy and bipolar radiofrequency ablation. Lasers Med Sci 2011; 26:545-52. [PMID: 21455786 DOI: 10.1007/s10103-011-0907-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 03/01/2011] [Indexed: 12/18/2022]
Abstract
Alternative minimally invasive treatment options such as radiofrequency ablation (RFA) or laser-induced thermotherapy (LITT) are at present under investigation for achieving a nonsurgical targeted cytoreduction in benign and malignant thyroid lesions. So far, studies have not been able to show a secure advantage for neither LITT nor RFA. The aim of this study was to compare the two ablation procedures in terms of their effectiveness. Thermal lesions were induced in porcine thyroid glands either by LITT or bipolar RFA ex vivo (n = 110 each) and in vivo (n = 10 each) using power settings between 10 and 20 W. Temperature spread during application was documented in 5- and 10-mm distance of the applicator. Postinterventional lesion diameters were measured and lesion size was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed in vivo. Lesion volumes induced by LITT ranged between 0.74 ± 0.18 cm(3) (10 W) and 3.80 ± 0.41 cm(3) (20 W) with a maximum of 5.13 ± 0.16 cm(3) at 18 W. The inducible lesion volumes by RFA were between 2.43 ± 0.68 cm(3) (10 W) and 0.91 ± 0.71 cm(3) (20 W) with a maximum of 2.80 ± 0.85 cm(3) at 14 W. The maximum temperatures were 112.9 ± 9.2°C (LITT) and 61.6 ± 13.9°C (RFA) at a distance of 5 mm and 73.2 ± 6.7°C (LITT) and 53.5 ± 8.6°C (RFA) at a distance of 10 mm. The histochemical analysis demonstrates a complete loss of NADPH dehydrogenase activity in thermal lesions as a sign of irreversible cell damage both for LITT and RFA. This study is the first to compare the effectiveness of laser-induced thermotherapy and radiofrequency ablation of thyroid tissue. LITT as well as RFA are suitable for singular thyroid nodules and induces reproducible clinically relevant lesions in an appropriate application time. The maximum inducible lesion volumes by LITT are significantly larger than by RFA with the devices used herein.
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Affiliation(s)
- Jörg-Peter Ritz
- Department of General, Vascular and Thoracic Surgery, Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12200, Berlin, Germany
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Renal Artery Embolization Combined With Radiofrequency Ablation in a Porcine Kidney Model: Effect of Small and Narrowly Calibrated Microparticles as Embolization Material on Coagulation Diameter, Volume, and Shape. Cardiovasc Intervent Radiol 2010; 34:156-65. [DOI: 10.1007/s00270-010-9908-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 05/20/2010] [Indexed: 12/18/2022]
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Zurbuchen U, Holmer C, Lehmann KS, Stein T, Roggan A, Seifarth C, Buhr HJ, Ritz JP. Determination of the temperature-dependent electric conductivity of liver tissue ex vivo and in vivo: Importance for therapy planning for the radiofrequency ablation of liver tumours. Int J Hyperthermia 2010; 26:26-33. [DOI: 10.3109/02656730903436442] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Holmer C, Lehmann KS, Knappe V, Zurbuchen U, Frericks B, Schumann T, Buhr HJ, Ritz JP. Bipolar radiofrequency ablation for nodular thyroid disease--ex vivo and in vivo evaluation of a dose-response relationship. J Surg Res 2009; 169:234-40. [PMID: 20097365 DOI: 10.1016/j.jss.2009.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 09/04/2009] [Accepted: 10/05/2009] [Indexed: 01/13/2023]
Abstract
BACKGROUND The prevalence of thyroid nodules ranges between 2% and 60% depending on the population studied. However, minimally invasive procedures like radiofrequency ablation (rfA) are increasingly used to treat tumors of parenchymatous organs, and seem to be suitable for singular thyroid nodules as well. Their successful clinical application depends on the induction of sufficiently large lesions and a knowledge of the energy parameters required for complete thermal ablation. The aim of this study was to establish a dose-response relationship for rfA of thyroid nodules. MATERIAL AND METHODS Thermal lesions were induced in healthy porcine thyroid glands ex vivo (n=110) and in vivo (n=10) using a bipolar radiofrequency system; rf was applied in a power range of 10-20 watts. During the ablation, continuous temperature measurement at a distance of 5 and 10 mm from the applicator was performed. The transversal and axial lesion diameters were measured, and the volume was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed. RESULTS The inducible lesion volumes were between 0.91±0.71 cm(3) at 20W and 2.80±0.85 cm(3) at 14W. The maximum temperatures after rf ablation were between 44.0±9.7°C and 61.6±13.9°C at a distance of 5 mm and between 30.0±8.6°C and 53.5±8.6°C at a distance of 10 mm from the applicator. The histochemical analysis demonstrates a complete loss of nicotinamide adenine dinucleotide phosphate-oxidase (NADPH) dehydrogenase activity in thermal lesions as a sign of irreversible cell damage. CONCLUSION This study is the first to demonstrate a dose-response relationship for rfA of thyroid tissue. rfA is suitable for singular thyroid nodules and induces reproducible, clinically relevant lesions with irreversible cell damage in an appropriate application time.
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Affiliation(s)
- Christoph Holmer
- Department of General, Vascular, and Thoracic Surgery, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.
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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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Ex situ quantification of the cooling effect of liver vessels on radiofrequency ablation. Langenbecks Arch Surg 2009; 394:475-81. [DOI: 10.1007/s00423-009-0480-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Accepted: 02/25/2009] [Indexed: 10/21/2022]
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Radiofrequency Ablation of Liver Tumors Using a Novel Bipolar Device. J Laparoendosc Adv Surg Tech A 2008; 18:857-63. [DOI: 10.1089/lap.2008.0260] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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Liu Z, Ahmed M, Gervais D, Humphries S, Goldberg SN. Computer Modeling of Factors that Affect the Minimum Safety Distance Required for Radiofrequency Ablation Near Adjacent Nontarget Structures. J Vasc Interv Radiol 2008; 19:1079-86. [DOI: 10.1016/j.jvir.2008.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 04/04/2008] [Accepted: 04/07/2008] [Indexed: 02/08/2023] Open
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MESH Headings
- Bone Neoplasms/diagnostic imaging
- Bone Neoplasms/secondary
- Bone Neoplasms/surgery
- Carcinoma, Hepatocellular/diagnostic imaging
- Carcinoma, Hepatocellular/surgery
- Carcinoma, Non-Small-Cell Lung/diagnostic imaging
- Carcinoma, Non-Small-Cell Lung/surgery
- Carcinoma, Renal Cell/diagnostic imaging
- Carcinoma, Renal Cell/surgery
- Cryosurgery/methods
- Electrocoagulation/methods
- Fluoroscopy
- Humans
- Image Processing, Computer-Assisted
- Imaging, Three-Dimensional
- Kidney Neoplasms/diagnostic imaging
- Kidney Neoplasms/surgery
- Liver Neoplasms/diagnostic imaging
- Liver Neoplasms/secondary
- Liver Neoplasms/surgery
- Lung Neoplasms/diagnostic imaging
- Lung Neoplasms/secondary
- Lung Neoplasms/surgery
- Neoplasms/diagnostic imaging
- Neoplasms/surgery
- Osteoma, Osteoid/diagnostic imaging
- Osteoma, Osteoid/surgery
- Radiology, Interventional
- Tomography, X-Ray Computed
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Affiliation(s)
- Michael Beland
- Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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