Radio-frequency tissue ablation: effect of pharmacologic modulation of blood flow on coagulation diameter.

Goldberg, S. Nahum; Hahn, P F; Halpern, E F; Fogle, R M; Gazelle, G. Scott

doi:10.1148/radiology.209.3.9844671

Cited by 210 publications

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“…Less heat will be conducted from the closest vicinity of the tip compared to the amount of heat conducted from non-coagulated tissue and the coagulated tissue will thus act as thermal insulation (Fig 2a). The latter model is supported by experimental studies of lesions made in liver with a similar temperature control as in this study (Aschoff et al 2001), or with internal cooling of the electrode (Goldberg et al 1998). Increased blood perfusion decreased lesion size in both cases.…”

Section: Discussionsupporting

confidence: 67%

Radio-frequency lesioning in brain tissue with coagulation-dependent thermal conductivity: modelling, simulation and analysis of parameter influence and interaction

et al. 2006

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Radio-frequency lesioning in brain tissue with coagulation-dependent thermal conductivity: modelling, simulation and analysis of parameter influence and interaction, 2006, Medical and Biological Engineering and Computing, (44) 2002-5772) and NIMED (Competence Center Noninvasive Medical Measurements). AbstractRadio-frequency brain lesioning is a method for reducing e.g. symptoms of movement disorders. A small electrode is used to thermally coagulate malfunctioning tissue.Influence on lesion size from thermal and electric conductivity of the tissue, microvascular perfusion and preset electrode temperature was investigated using a finite element model. Perfusion was modelled as an increased thermal conductivity in noncoagulated tissue. The parameters were analysed using a 2 4 -factorial design (n=16) and quadratic regression analysis (n=47). Increased thermal conductivity of the tissue increased lesion volume, while increased perfusion decreased it since coagulation creates a thermally insulating layer due to the cessation of blood perfusion. These effects were strengthened with increased preset temperature. The electric conductivity had negligible effect. Simulations were found realistic compared to in vivo experimental lesions.Johansson et al. 2010-01-183

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Section: Discussionsupporting

confidence: 67%

Radio-frequency lesioning in brain tissue with coagulation-dependent thermal conductivity: modelling, simulation and analysis of parameter influence and interaction

et al. 2006

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“…Curley et al [14] have used the Pringle method [15] intraoperatively to reduce liver blood flow, by temporarily stopping portal vein and hepatic artery www.wjgnet.com flow, and improving ablation outcomes. Goldberg et al [16] have used vascular agents, such as halothane, vasopressin and adrenaline, to adjust liver blood volume in order to increase ablation area. TACE is one of the major interventional methods for HCC treatment, and when performed before RFA, it can increase therapeutic efficacy as a result of the decreased heat sink effect [17][18][19] .…”

Section: Discussionmentioning

confidence: 99%

Adjuvant percutaneous radiofrequency ablation of feeding artery of hepatocellular carcinoma before treatment

Hou¹,

Chen²,

Yan³

et al. 2009

WJG

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AIM:To evaluate the feasibility and efficacy of percutaneous radiofrequency ablation (RFA) of the feeding artery of hepatocellular carcinoma (HCC) in reducing the blood-flow-induced heat-sink effect of RFA. METHODS:A total of 154 HCC patients with 177 pathologically confirmed hypervascular lesions participated in the study and were randomly assigned into two groups. Seventy-one patients with 75 HCCs (average tumor size, 4.3 ± 1.1 cm) were included in group A, in which the feeding artery of HCC was identified by color Doppler flow imaging, and were ablated with multiple small overlapping RFA foci [percutaneous ablation of feeding artery (PAA)] before routine RFA treatment of the tumor. Eighty-three patients with 102 HCC (average tumor size, 4.1 ± 1.0 cm) were included in group B, in which the tumors were treated routinely with RFA. Contrast-enhanced computed tomography was used as post-RFA imaging, when patients were followed-up for 1, 3 and 6 mo. RESULTS:In group A, feeding arteries were blocked in 66 (88%) HCC lesions, and the size of arteries decreased in nine (12%). The average number of punctures per HCC was 2.76 ± 1.12 in group A, and 3.36 ± 1.60 in group B (P = 0.01). The tumor necrosis rate at 1 mo post-RFA was 90.67% (68/75 lesions) in group A and 90.20% (92/102 lesions) in group B. HCC recurrence rate at 6 mo post-RFA was 17.33% (13/75) in group A and 31.37% (32/102) in group B (P = 0.04).CONCLUSION: PAA blocked effectively the feeding artery of HCC. Combination of PAA and RFA significantly decreased post-RFA recurrence and provided an alternative treatment for hypervascular HCC. INTRODUCTIONHepatocellular carcinoma (HCC) is the fifth most common cancer in the world (564 000 cases per year) and the third most frequent cause of cancer-related death [1] . Surgical resection is considered to be potentially curative therapy. However, only about 20% of HCC patients are eligible for resection [1,2] ; the remainder are ineligible because of multifocal tumors, advanced tumors, tumor location precluding complete resection, or poor hepatic functional reserve. Therefore, a variety of imaging-guided tumor ablation therapies such as ethanol injection, microwave coagulation, percutaneous radiofrequency ablation (RFA) and laser ablation are often considered as alternative options [3][4][5][6] . Among them, RFA has been used increasingly as a safe technique for treating hepatic tumors [7][8][9] . However, for hypervascular HCC, RFA appears less effective because of a blood-flow-induced heat sink effect, which might BRIEF ARTICLESwww.wjgnet.com cause incomplete ablation or recurrence [10] . Transcatheter arterial chemoembolization (TACE) can reduce blood supply of HCC by occlusion of tumor arteries, and the efficacy of combination TACE and RFA has been confirmed [11,12] . Treatment difficulty remains for those patients who cannot tolerate or are ineligible for TACE because of liver cirrhosis or difficulty in manipulation of vessels with abnormal curvature that have resulted from surgical resection and liver ...

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“…One possible explanation for this discrepancy is that hepatic blood flow may have a cooling effect and could thus have influenced the ablative state in the clinical cases. By contrast, ex vivo bovine liver was not perfused with blood flow (17)(18)(19). Previous studies have demonstrated that a reduction in blood supply, such as in transcatheter arterial chemoembolization, results in enlarged ablative volume (20)(21)(22).…”

Section: Discussionmentioning

confidence: 99%

Comparison between different thickness umbrella-shaped expandable radiofrequency electrodes (SuperSlim and CoAccess): Experimental and clinical study

Koda

Tokunaga

Matono

et al. 2011

Experimental and Therapeutic Medicine

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Abstract. The purpose of the present study was to compare the size and configuration of the ablation zones created by SuperSlim and CoAccess electrodes, using various ablation algorithms in ex vivo bovine liver and in clinical cases. In the experimental study, we ablated explanted bovine liver using 2 types of electrodes and 4 ablation algorithms (combinations of incremental power supply, stepwise expansion and additional low-power ablation) and evaluated the ablation area and time.In the clinical study, we compared the ablation volume and the shape of the ablation zone between both electrodes in 23 hepatocellular carcinoma (HCC) cases with the best algorithm (incremental power supply, stepwise expansion and additional low-power ablation) as derived from the experimental study. In the experimental study, the ablation area and time by the CoAccess electrode were significantly greater compared to those by the SuperSlim electrode for the single-step (algorithm 1, p=0.0209 and 0.0325, respectively) and stepwise expansion algorithms (algorithm 2, p=0.0002 and <0.0001, respectively; algorithm 3, p= 0.006 and 0.0407, respectively). However, differences were not significant for the additional low-power ablation algorithm. In the clinical study, the ablation volume and time in the CoAccess group were significantly larger and longer, respectively, compared to those in the SuperSlim group (p=0.0242 and 0.009, respectively). Round ablation zones were acquired in 91.7% of the CoAccess group, while irregular ablation zones were obtained in 45.5% of the SuperSlim group (p= 0.0428). In conclusion, the CoAccess electrode achieves larger and more uniform ablation zones compared with the SuperSlim electrode, though it requires longer ablation times in experimental and clinical studies.

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Radio-frequency tissue ablation: effect of pharmacologic modulation of blood flow on coagulation diameter.

Abstract: The coagulation necrosis achieved for a standardized RF application correlates with relative tissue perfusion. Pharmacologic reduction of blood flow during thermally mediated percutaneous ablation may induce greater coagulation necrosis.

Cited by 210 publications

References 0 publications

Radio-frequency lesioning in brain tissue with coagulation-dependent thermal conductivity: modelling, simulation and analysis of parameter influence and interaction

Radio-frequency lesioning in brain tissue with coagulation-dependent thermal conductivity: modelling, simulation and analysis of parameter influence and interaction

Adjuvant percutaneous radiofrequency ablation of feeding artery of hepatocellular carcinoma before treatment

Comparison between different thickness umbrella-shaped expandable radiofrequency electrodes (SuperSlim and CoAccess): Experimental and clinical study

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