Simulation of Radiofrequency Ablation Including Water Evaporation

Pätz, Torben; Kröger, Tim; Preußer, Tobias

doi:10.1007/978-3-642-03882-2_341

Cited by 28 publications

(22 citation statements)

References 6 publications

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“…5 At temperatures above 100ºC vaporization occurs and desiccation implies a rapid drop of . There are also discrepancies about the rate of this drop: Byeongman and Aksan [13] considered that  decreases by approximately 2 orders of magnitude between 105ºC and 110ºC, Haemmerich et al [14] assumed a rapid drop by a factor of 10.000 between 100ºC and 102ºC, and Pätz et al [19] considered a discontinuous drop to a value close to zero.…”

Section: Temperature-dependence Of Electrical Conductivity (mentioning

confidence: 99%

“…tissue at temperatures below 100ºC) and the post-phase-change tissue (i=g, i.e. tissue at temperatures above 100ºC), h fg is the product of water latent heat of vaporization and water density at 100ºC and C is tissue water content inside the liver (68%) [19]. The notation h(99) and h(100) refers to enthalpy at 99 and 100ºC, respectively.…”

Section: Description Of the Model Of Rf Hepatic Ablationmentioning

confidence: 99%

“…The notation h(99) and h(100) refers to enthalpy at 99 and 100ºC, respectively. The characteristics of materials used in the model are shown in Table 2 [12,19,29,30].…”

Section: Description Of the Model Of Rf Hepatic Ablationmentioning

confidence: 99%

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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: Temperature-dependence Of Electrical Conductivity (mentioning

confidence: 99%

Section: Description Of the Model Of Rf Hepatic Ablationmentioning

confidence: 99%

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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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“…The thermal and electrical properties of the model elements are shown in Table I [ [21][22][23][24]. Due to the lack of information on the electrical and thermal characteristics of the pericardial fluid we assumed it to have the same characteristics as saline [22] as a first approximation.…”

Section: Computer Modelingmentioning

confidence: 99%

Radiofrequency cardiac ablation with catheters placed on opposing sides of the ventricular wall: Computer modelling comparing bipolar and unipolar modes

González-Suárez

Trujillo

Koruth³

et al. 2014

International Journal of Hyperthermia

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Koruth, J.; Berjano, E. (2014). Radiofrequency cardiac ablation with catheters placed on opposing sides of the ventricular wall: Computer modelling comparing bipolar and unipolar modes. International Journal of Hyperthermia. 30 (6) Materials and methods:We built computational models to study the temperature distributions and lesion dimensions created by BM and UM on IVS and VFW during RFA. Two different UM types were considered: sequential (SEUM) and simultaneous (SIUM). The effect of ventricular wall thickness, catheter misalignment, epicardial fat, and presence of air in the epicardial space were also studied.Results: As regards IVS ablation, BM created transmural and symmetrical lesions for wall thicknesses up to 15 mm. SEUM and SIUM were not able to create transmural lesions with IVS thicknesses ≥ 12.5 and 15 mm, respectively. Lesions were asymmetrical only with SEUM. For VFW ablation, BM also created transmural lesions for wall thicknesses up to 15 mm. However, with SEUM and SIUM transmurality was obtained for VFW thicknesses ≤ 7.5 and 12.5 mm, respectively. With the three modes VFW lesions were always asymmetrical. In the scenario with air or a fat tissue layer on the epicardial side, only SIUM was capable of creating transmural lesions. Overall, BM was superior to UM in IVS and VFW ablation when the catheters were not aligned. Conclusions:Our findings suggest that BM is more effective than UM in achieving transmurality across both ventricular sites, except in the situation of the epicardial catheter tip surrounded by air or placed over a fat tissue layer.

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“…We considered a latent heat value of 2.162·10 9 J m −3 , which corresponds to the product of the water vaporization latent heat and the water density at 150 100ºC, and a tissue water content of 0.68 inside the liver tissue. 14 The distributed heat sink effect of the microvascular perfusion was included in the tissue considering as:…”

Section: Iic Computer Modelingmentioning

confidence: 99%

Could the heat sink effect of blood flow inside large vessels protect the vessel wall from thermal damage during RF‐assisted surgical resection?

et al. 2014

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A.; Trujillo Guillen, M.; Andaluz, A.; Berjano, E. (2014). Could the heat sink effect of blood flow inside large vessels protect the vessel wall from thermal damage during RF-assisted surgical resection?. Medical Physics. 41 (8) the cases considered. Thermal damage to the portal vein wall was inversely related to the vessel-device distance. It was also more pronounced when the device-tissue contact surface was reduced or when the vessel was parallel to the device or perpendicular to its distal end (blade zone), the vessel wall being damaged at distances less than 4.25 mm. Conclusions:Our computational findings suggest that the heat sink effect could protect 40 the portal vein wall for distances equal to or greater than 5 mm, regardless of its position and distance with respect to the RF-based device.

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Simulation of Radiofrequency Ablation Including Water Evaporation

Cited by 28 publications

References 6 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

Radiofrequency cardiac ablation with catheters placed on opposing sides of the ventricular wall: Computer modelling comparing bipolar and unipolar modes

Could the heat sink effect of blood flow inside large vessels protect the vessel wall from thermal damage during RF‐assisted surgical resection?

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