Percutaneous Radiofrequency Ablation of Liver Tumors with the LeVeen Probe: Is Roll-off Predictive of Response?

Arata, Michael A.; Nisenbaum, Harvey L.; Clark, Timothy W.I.; Soulen, Michael C.

doi:10.1016/s1051-0443(07)61884-3

Cited by 63 publications

(36 citation statements)

References 7 publications

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“…The system is based on switching at each impedance spike (>30 Ω above baseline) because sharp rises in impedance are associated with tissue coagulation and vascular thrombosis, both desirable endpoints for creating a conglomerate zone of coagulation (32,33). Instead of temporarily switching the system off when an impedance spike is encountered, the generator powers a second electrode to an impedance spike, and then a third, etc.…”

Section: Discussionmentioning

confidence: 99%

Multiple-Electrode Radiofrequency Ablation Creates Confluent Areas of Necrosis: In Vivo Porcine Liver Results

Laeseke

Sampson²,

Haemmerich

et al. 2006

Radiology

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PURPOSE-To prospectively evaluate an impedance-based multiple-electrode RF ablation system for creation of confluent areas of hepatic coagulation in an in vivo porcine model. MATERIALS & METHODS-Pre-approval was obtained from our institutional research animal care and use committee. A prototype multiple-electrode RF system was created allowing switching between three electrically-independent electrodes at impedance spikes (30 Ω increase). Forty-two coagulation zones [single=18, cluster=12, multiple-electrode (three singles spaced 2 cm apart)=12] were created at laparotomy in fifteen ~90 kg female pigs. Half of the ablations were performed for 12 minutes and half for 16 minutes. Coagulation zones were excised and sliced (~3 mm) for measurements. ANOVA and two sample t-tests (Bonferroni's correction, α=.0033) were used to test for differences between groups.RESULTS-At 12 minutes, mean (±SD) multiple-electrode coagulation was significantly larger than single (minimum diameter: 2.8±0.6 vs. 1.6±0.6 cm; maximum diameter: 4.2±0.7 vs. 2.0± 0.5 cm; volume: 22.1±10.7 vs. 6.7±3.7 cm 3 ; P<.0033, all comparisons). Multiple-electrode maximum diameter was significantly larger than cluster at 12 minutes (4.2±0.7 vs. 2.9±0.3 cm, P=.02). At 16 minutes, multiple-electrode coagulation zones (minimum diameter: 3.2±0.6 cm; maximum diameter: 4.2±0.6 cm; volume: 29.1±8.3 cm 3 ) were significantly greater than single (minimum diameter: 1.7±0.5 cm; maximum diameter: 2.2±0.6 cm; volume: 7.1±3.5 cm 3 ; P<.0033, all comparisons) and cluster controls (minimum diameter: 2.3±0.3 cm, P=.007; maximum diameter: 3.2±0.4 cm, P=.005; volume: 13.1±3.0 cm 3 , P<.0033).

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Section: Discussionmentioning

confidence: 99%

Multiple-Electrode Radiofrequency Ablation Creates Confluent Areas of Necrosis: In Vivo Porcine Liver Results

Laeseke

Sampson²,

Haemmerich

et al. 2006

Radiology

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“…In addition, in the first few seconds tissue temperature can reach up to 100ºC in these zones, which is associated with the gas bubbles observed by means of ultrasound guidance [10].…”

Section: Radiofrequency (Rf) Ablation (Rfa) Is a Minimally Invasive Amentioning

confidence: 91%

Relationship between roll-off occurrence and spatial distribution of dehydrated tissue during RF ablation with cooled electrodes

Trujillo

Alba

Berjano

2012

International Journal of Hyperthermia

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Berjano, E. (2012). Relationship between roll-off occurrence and spatial distribution of dehydrated tissue during RF ablation with cooled electrodes. International Journal of Hyperthermia. 28 (1) AbstractPurpose: To study the relationship between roll-off (sudden increase in impedance) and spatial distribution of dehydrated tissue during RF ablation using a cooled electrode (temperatures around 100ºC). Methods:We used a double approach: 1) theoretical modeling based on the Finite Element Method; and 2) 20 ablations using an experimental study on ex-vivo excised bovine liver in which we measured impedance progress and temperature at three points close to the electrode surface: 0.5 (T1), 1.5 (T2) and 2.5 (T3) mm from the tip. T2 was located exactly at the center of the 30 mm long electrode.Results: Temperatures at T1 and T3 quickly rose to 100ºC (at ≈ 20 and 40 s, respectively), while at the rise at T2 was somewhat slower, stabilized around 50 s and reached a maximum value of 99ºC at about 60 s. Impedance reached a minimum of 65  (plateau), began increasing at 50 s and continued rising throughout the procedure, reaching a value equal to the initial value at 70 s. Likewise, computed impedance dropped to ≈73  (plateau), began increasing at 50 s and reached an impedance value equal to the initial value at ≈78 s, which approximately coincided with the time when the entire zone surrounding the electrode was within the 100ºC isotherm. Conclusion:There is a close relationship between the moment at which roll-off occurs and the time when the entire electrode is completely encircled by the dehydrated tissue. The midelectrode zone is the last in which tissue dessication occurs.

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“…where  i and c i were tissue density and specific heat of normal tissue (i=l) and the postphase-change tissue (i=g), respectively, h fg was the product of water latent heat of vaporization and water density at 100ºC and C was tissue water content inside the liver (68%) [25].…”

Section: Theoretical Model: Rf Problemmentioning

confidence: 99%

Can electroporation previous to radiofrequency hepatic ablation enlarge thermal lesion size? A feasibility study based on theoretical modelling andin vivoexperiments

Trujillo

Castellví

Burdı́o

et al. 2013

International Journal of Hyperthermia

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Castellvi, Q.; Burdío, F.; Sánchez Velázquez, P.; Ivorra, A.; Andaluz, A.; Berjano, E. (2013). Can electroporation previous to radiofrequency hepatic ablation enlarge thermal lesion size? A feasibility study based on theoretical modelling and in vivo experiments. AbstractPurpose: To assess the feasibility of a hybrid ablative technique based on applying electroporation (EP) pulses just before conducting radiofrequency ablation (RFA). The rationale was that the EP-induced reduction in blood perfusion could be sufficient to reduce the thermal sink effect and hence to increase the coagulation volume in comparison to that created exclusively by RFA. Materials and methods:Modeling study and in vivo experimental study. A Cool-tip RF applicator was used both for EP and RFA.Results: Overall, the results did not show any synergy effect from using the hybrid technique. Applying EP pulses prior to RFA did not increase the coagulation zone obtained and the lesions were almost identical. Additional computer simulations provided an explanation for this; the effect of reducing blood perfusion by thermal damage during RFA completely masks the effect of reducing blood perfusion by EP. This is because both thermal damage and EP affect the same zone, i.e. the tissue around the electrode. Conclusions:Our computer modeling and in vivo experimental findings suggest that the combination of EP and RFA with monopolar applicators does not provide an additional benefit over the use of RFA alone.

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Percutaneous Radiofrequency Ablation of Liver Tumors with the LeVeen Probe: Is Roll-off Predictive of Response?

Cited by 63 publications

References 7 publications

Multiple-Electrode Radiofrequency Ablation Creates Confluent Areas of Necrosis: In Vivo Porcine Liver Results

Multiple-Electrode Radiofrequency Ablation Creates Confluent Areas of Necrosis: In Vivo Porcine Liver Results

Relationship between roll-off occurrence and spatial distribution of dehydrated tissue during RF ablation with cooled electrodes

Can electroporation previous to radiofrequency hepatic ablation enlarge thermal lesion size? A feasibility study based on theoretical modelling andin vivoexperiments

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