Investigation of radiofrequency ablation process in liver tissue by finite element modeling and experiment

Barauskas, Rimantas; Gulbinas, Antanas; Barauskas, Giedrius

doi:10.3390/medicina43040039

Cited by 27 publications

(22 citation statements)

References 11 publications

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“…A good result in this area would provide the necessary information for the accurate modeling of  and k. The current lack of this information means that it necessary to assess the impact of the common mathematical functions used to model the temperature dependence of  and k in RFA. Temperature profiles obtained in the simulations are relevant and typically found in a RF ablation regime, which validates our results in other RF problems (see for example [21] and [35]). …”

Section: Discussionsupporting

confidence: 75%

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Review of the mathematical functions used to model the temperature dependence of electrical and thermal conductivities of biological tissue in radiofrequency ablation

Trujillo

Berjano

2013

International Journal of Hyperthermia

126

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Purpose: Although theoretical modeling is widely used to study different aspects of radiofrequency ablation (RFA) its utility is directly related to its realism. An important factor in this realism is the use of mathematical functions to model the temperaturedependence of tissue thermal (k) and electrical () conductivities. Our aim was to review the piecewise mathematical functions most commonly used for modeling the temperaturedependence of k and  in RFA computational modeling. Materials and methods:We built a hepatic RFA theoretical model of a cooled electrode and compared lesion dimensions and impedance evolution with combinations of mathematical functions proposed in previous studies We employed the thermal damage contour D63 to compute the lesion dimension contour, which corresponds to Ω= 1, Ω being local thermal damage assessed by the Arrhenius damage model. Results:The results were very similar in all cases in terms of impedance evolution and lesion size after 6 minutes of ablation. Although the relative differences between cases in terms of time to first roll-off (abrupt increase in impedance) were as much as 12%, the maximum relative differences in terms of the short lesion (transverse) diameter were below 3.5%. Conclusions:The findings suggest that the different methods of modeling temperature dependence of k and  reported in the literature do not significantly affect the computed lesion diameter.3

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Section: Discussionsupporting

confidence: 75%

“…As regards , some studies have considered a temperature-dependence based on a polynomial relation derived from NaCl solutions [21,35]. Ji and Brace [36] recently have suggested that variations in liver electrical conductivity at temperatures near 100ºC are best modeled using a sigmoid function for microwave thermal ablation.…”

Section: Discussionmentioning

confidence: 99%

Review of the mathematical functions used to model the temperature dependence of electrical and thermal conductivities of biological tissue in radiofrequency ablation

Trujillo

Berjano

2013

International Journal of Hyperthermia

126

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“…Coagulation of tissue is induced at temperatures between 60 °C and 100 °C and manifests as an irreversible damage to mitochondrial and cytosolic enzymes of the cells. The temperature decreases away from the active probe and is reflected by different morphological changes in the affected tissues (Barauskas et al 2007b). These changes are morphologically described as four zones: 1 -application, 2 -central, 3 -transition and 4 -reference tissue zone.…”

Section: Discussionmentioning

confidence: 99%

Healing dynamics of porcine pancreatic parenchyma after radiofrequency ablation - in vivo experimental pilot study

et al. 2012

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Radiofrequency ablation is a tumour destruction method, widely used in human as well veterinary medicine. Recently, it has been applied to pancreatic disorder treatment. However, little is known about healing of the pancreatic parenchyma after radiofrequency ablation as it is important for the prevention of complications and treatment strategy. The aim of this experimental in vivo study on pigs was to evaluate the pancreatic parenchyma healing dynamics after damage by radiofrequency ablation. Radiofrequency ablations of the duodenal lobe of the pancreas were performed on 8 cross-bred laboratory pigs. They were euthanized in pairs at seven, fourteen, forty and eighty days after the procedure. Histological and cytological changes of the ablated zone were evaluated after autopsy. It was proved that pancreatic necrosis after radiofrequency ablation heals by means of fibrotic scar. There was no sign of exocrine and endocrine regeneration, respectively, during 80 days after the procedure. This is the first study verifying that the healing process of an ablation zone in the pancreatic parenchyma after radiofrequency ablation is similar to healing in the liver, lung, heart and other parenchymal organs.

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“…In axisymmetric formulation, the partial differential equation (PDE), which describes the infiltration process in each finite element V reads as: [1] where: p pressure presented as hydraulic head, measured in terms of height of equivalent water column [ Cauchy boundary conditions defining the flux density at infusion eyeholes;…”

Section: Mathematical Equationsmentioning

confidence: 99%

“…The infiltrating flow of the saline makes significant influence on the overall heat transfer process taking place during RFA due to certain amount of heating energy transferred into the tissue by advection, which is the transport of heat in a vector field of solution flow velocities (1). Together with the thermal conductivity of tissues, the two heat transfer mechanisms complete the full physical view of thermal processes to be taken into account in the mathematical description of RFA ex vivo experiments.…”

Section: Introductionmentioning

confidence: 99%

Finite element modeling and experimental investigation of infiltration of sodium chloride solution into nonviable liver tissue

Barauskas

Gulbinas²,

Barauskas³

2007

Medicina

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Summary. The aim of this study was to establish a mathematical model of the infiltration of sodium chloride solution into cadaveric liver tissue.Methods. The time law of the flow of the infiltrated fluid at every node of the finite element model was obtained in terms of Darcys velocity, pressure, and volumetric saturation fraction. The model equations interpret the liver tissue as a porous medium taking into account the hydraulic conductivity, capacity, and absorption mechanisms. Capability of the cadaveric liver tissue to absorb the fluid is taken into account by means of the nonlinear relationship of hydraulic capacity and absorption coefficients against the volumetric saturation fraction. To explain certain inadequacies between the computational model and experiment, the idealized models of empty blood vessels in the vicinity of the injection probe have been used. The model has been implemented in computational environment COMSOL Multiphysics.Experimental procedures were performed to analyze fluid infiltration and to calculate volume of fluid, which might be injected into certain volume of nonviable liver tissue.Results. The necessary physical constants of hydraulic conductivity, capacity, and absorption of liver tissue have been determined by comparing the simulation results against the experimental data. The congruence of the modeling results against the experiment may be regarded as satisfactory.Conclusion. The established model analyses distribution of injected solution taking into account the hydraulic conductivity, capacity, and absorption mechanisms of liver tissue. The obtained results are of importance developing complex models of electro-thermal heating coupled with heat advection by means of infiltrated sodium chloride solution.Medicina (Kaunas) 2007; 43(5)

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Investigation of radiofrequency ablation process in liver tissue by finite element modeling and experiment

Abstract: Medicina (Kaunas) 2007; 43(4)

Cited by 27 publications

References 11 publications

Review of the mathematical functions used to model the temperature dependence of electrical and thermal conductivities of biological tissue in radiofrequency ablation

Review of the mathematical functions used to model the temperature dependence of electrical and thermal conductivities of biological tissue in radiofrequency ablation

Healing dynamics of porcine pancreatic parenchyma after radiofrequency ablation - in vivo experimental pilot study

Finite element modeling and experimental investigation of infiltration of sodium chloride solution into nonviable liver tissue

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