<b>Radiofrequency Ablation of Hepatic Tumors:</b> Variability of Lesion Size Using a Single Ablation Device

Montgomery, Richard S.; Rahal, Andres; Dodd, Gerald D.; Leyendecker, John R.; Hubbard, Linda G.

doi:10.2214/ajr.182.3.1820657

Cited by 73 publications

(35 citation statements)

References 13 publications

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“…The modified automated algorithm [9, 10, 12, 13] begins by activating the impedance control mode with a gradual increase in power output over the first minute to reach 120 W. Power is maintained at this level until tissue impedance rises 20 Ω above the baseline impedance. Once the 20 Ω of threshold is exceeded, the power output is automatically reduced to zero for 15 s. Power is then returned to the initial peak power setting until the tissue impedance rises again.…”

Section: Methodsmentioning

confidence: 99%

Treatment of Hepatocellular Carcinoma Using Internally Cooled Electrodes

Y.¹,

Lin²,

Lin³

et al. 2007

Oncology

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Objectives: To compare the effectiveness of modified automated and manual pulsed radiofrequency (RF) algorithms using internally cooled electrodes for hepatocellular carcinoma (HCC). Methods: Seventy-seven treatment-naive cirrhotic patients with 102 HCC (≤4 cm) underwent 109 sessions of ultrasound-guided percutaneous RF ablation using a 17-gauge, 20-cm-long, single internally cooled electrode. Patients were assigned alternatively: 40 patients to the modified automated algorithm group and 37 patients to the manual algorithm group. The mean tumor diameters were 2.34 ± 0.9 and 2.25 ± 0.7 cm in the automated and manual groups, respectively (p = 0.56). Primary technique effectiveness and local tumor progression were compared between the two groups. Results: More overlapping ablations (n = 112) were required in the manual than in the automated group (n = 82) to achieve similar primary technique effectiveness rates of 96.1 and 94.1%, respectively. After a mean follow-up period of 26.7 ± 1.1 months, the local tumor progression rates at 12 and 18 months were 4 and 20% in the manual group and 12 and 24% in the modified automated group (p = 0.3). Only tumors >3 cm were independently associated with local tumor progression (odds ratio 1.25; 95% CI 1.06–2.34, p = 0.03). Conclusions: The manual algorithm requires more overlapping ablations and treatment sessions in order to achieve similar primary technique effectiveness and local tumor progression rates compared with the modified automated algorithm.

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Section: Methodsmentioning

confidence: 99%

Treatment of Hepatocellular Carcinoma Using Internally Cooled Electrodes

Y.¹,

Lin²,

Lin³

et al. 2007

Oncology

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“…None have focused on a direct comparison of different experimental results in terms of coagulation zone size and the evolution of electrical variables. The task is even harder if clinical results are used, since they can vary immensely, from 1.7 to 5.3 cm [34]. This is possibly due to variations in tissue characteristics and procedural factors, such as multiple applications of RF power on the same target to increase total coagulation zone size by overlapping.…”

Section: Limitations Of the Studymentioning

confidence: 99%

Computer modelling of an impedance-controlled pulsing protocol for RF tumour ablation with a cooled electrode

Trujillo

Bon

Rivera

et al. 2016

International Journal of Hyperthermia

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Purpose: To develop computer models to mimic the impedance-controlled pulsing protocol implemented in RF generators used for clinical practice of radiofrequency ablation (RFA), and to assess the appropriateness of the models by comparing the computer results with those obtained in previous experimental studies.Methods: A 12-minute RFA was modeled using a cooled electrode (17G, 3 cm tip) inserted in hepatic tissue. The short (transverse) diameter of the coagulation zone was assessed under in vivo (with blood perfusion and considering clamping) and ex vivo (at 21ºC) conditions.The computer results obtained by programming voltage pulses were compared with current pulses.Results: The differences between voltage and current pulses protocol were noticeable: using current instead of voltage allows larger coagulation zones to be created, due to the higher energy applied by current pulses. If voltage pulses are employed, the model can accurately predict number of roll-offs, although the waveform of the applied power is clearly not realistic. If current voltages are employed, the applied power waveform matches well with those reported experimentally, but there are significantly fewer roll-offs. Our computer results were overall into the ranges of experimental ones. Conclusions:The proposed models reproduce reasonably well the electrical-thermal performance and coagulation zone size obtained during an impedance-controlled pulsing protocol.

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“…However, none of these approaches provides the physician performing the procedure with vital information concerning induced lesion size while the patient is still on the operating table. As a recent study (Montgomery et al 2004) has demonstrated that identical ablation equipment and treatment protocols can produce lesions of markedly different sizes in different patients, monitoring the size of the induced thermal lesion during RF ablation procedures is essential to optimize the safety and success of the technique.…”

Section: Introductionmentioning

confidence: 99%

Liver ablation guidance with acoustic radiation force impulse imaging: challenges and opportunities

et al. 2006

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Previous studies have established the feasibility of monitoring radiofrequency (RF) ablation procedures with acoustic radiation force impulse (ARFI) imaging. However, questions remained regarding the utility of the technique in clinically realistic scenarios and at scanning depths associated with abdominal imaging in adults. We address several of these issues and detail recent progress towards the clinical relevance of the ARFI technique. Results from in vitro bovine tissues and an in vivo ovine model are presented. Additional experiments were conducted with a tissue-mimicking phantom and parallel receive tracking techniques in order to further support the clinical feasibility of the method. Thermal lesions created during RF ablation are visualized with high contrast in both in vitro and in vivo hepatic tissues, and radial lesion growth can be monitored throughout the duration of the procedure. ARFI imaging is implemented on a diagnostic ultrasonic scanner, and thus may be a convenient option to guide RF ablation procedures, particularly when electrode insertion is also performed with sonographic guidance.

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Radiofrequency Ablation of Hepatic Tumors: Variability of Lesion Size Using a Single Ablation Device

Abstract: Significant variation occurs in the lesion size produced using the same ablation device and algorithm. These findings must be considered when planning ablation strategies.

Cited by 73 publications

References 13 publications

Treatment of Hepatocellular Carcinoma Using Internally Cooled Electrodes

Treatment of Hepatocellular Carcinoma Using Internally Cooled Electrodes

Computer modelling of an impedance-controlled pulsing protocol for RF tumour ablation with a cooled electrode

Liver ablation guidance with acoustic radiation force impulse imaging: challenges and opportunities

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