Effect of blood flow and metabolism on multidimensional heat transfer during cryosurgery

Zhao, Gang; Zhang, Haifeng; Guo, Xiaojie; Luo, Dawei; Gao, Dayong

doi:10.1016/j.medengphy.2006.03.005

Cited by 64 publications

(32 citation statements)

References 39 publications

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“…Likewise, Q m was not considered because it is negligible in comparison to the other terms during RFCA [3]. In biological tissues, enthalpy is related to temperature by the following expression [25,27]:…”

Section: B Governing Equationsmentioning

confidence: 99%

Comparative Analysis of Different Methods of Modeling the Thermal Effect of Circulating Blood Flow During RF Cardiac Ablation

González-Suárez

Berjano

2016

IEEE Trans. Biomed. Eng.

146

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Abstract-Goal: Our aim was to compare the different methods of modeling the effect of circulating blood flow on the thermal lesion dimensions created by radiofrequency cardiac ablation and on the maximum blood temperature. Methods: Computational models were built to study the temperature distributions and lesion dimensions created by a non-irrigated electrode by two radiofrequency energy delivery protocols (constant voltage and constant temperature) under high and low blood flow conditions. Four methods of modeling the effect of circulating blood flow on lesion dimensions and temperature distribution were compared. Three of them considered convective coefficients at the electrode-blood and tissue-blood interfaces to model blood flow: 1) without including blood as a part of the domain; 2) constant electrical conductivity of blood; and 3) temperature-dependent electrical conductivity of blood (+2%/ºC). Method 4) included blood motion and was considered to be a reference method for comparison purposes. Results: Only Method 4 provided a realistic blood temperature distribution. The other three methods predicted lesion depth values similar to those of the reference method (differences smaller than 1 mm), regardless of ablation mode and blood flow conditions. Conclusion: Considering the aspects of lesion size and maximum temperature reached in blood and tissue, Method 2 seems to be the most suitable alternative to Method 4 in order to reduce the computational complexity. Significance: Our findings could have an important implication in future studies of RF cardiac ablation, in particular, in choosing the most suitable method to model the thermal effect of circulating blood.

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Section: B Governing Equationsmentioning

confidence: 99%

Comparative Analysis of Different Methods of Modeling the Thermal Effect of Circulating Blood Flow During RF Cardiac Ablation

González-Suárez

Berjano

2016

IEEE Trans. Biomed. Eng.

146

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“…For biological tissues enthalpy is related to tissue temperature by the following expression [25,28]:…”

Section: Description Of the Model Of Rf Hepatic Ablationmentioning

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

123

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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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“…Considering that a typical value of the blood perfusion rate B is 17 kW/(m 3 ·K) (ρb = 1000 kg/m 3 , ω = 0.005 1/s and cb = 3391 J/kg·K) in soft tissues in previous studies (Zhao et al, 2007;Duck, 1990;Seyde et al, 1985;Koehler et al, 1985) we assumed B as a parameter ranging from 0 to 50 kW/(m 3 ·K). The given apparent thermal conductivity and heat capacity were expressed by the ratio to that of tissue by ɛ (=kap/k) and  (=cap/c), respectively.…”

Section: Methodsmentioning

confidence: 99%

“…In addition, the estimation from these models was not significantly different from the Pennes equation that was practically used for a rat liver (Valvano et al, 1984) and a pig kidney (Xu, 1991). Consequently, the Pennes bioheat equation has still been used for a number of applications (Zhao et al, 2005;Dehghan and Sabouri, 2012;Shahnazari et al, 2013) assuming constant blood perfusion (Li et al, 2002;Zhao et al, 2007) or temperature-dependent perfusion rate (Sanyal and Maji, 2001;Gang et al, 2007). However, in many cases for human tissues, even the blood perfusion rate is not available and is dependent on tissue types (Shitzer and Eberhart, 1985).…”

Section: Introductionmentioning

confidence: 99%

Feasibility of using apparent thermophysical properties to incorporate the effect of blood perfusion in estimation of temperature in tissues

Shurrab

Wang

Fukunaga

et al. 2017

JTST

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Estimation of temperature distribution in tissues and organs is critically important for treatments such as hyperthermia, radiofrequency ablation and cryosurgery which expose malignant tissue to extreme temperatures that are different from the physiological temperature. Commonly, the bioheat equation, instead of heat conduction equation, is used for estimation to incorporate the effect of blood perfusion, because the heat transfer in tissues is significantly affected by blood perfusion in addition to thermophysical properties of tissues. Nevertheless, in many cases, the rate of blood perfusion is not available for human tissues and organs. This study therefore aims to examine if we can use the normal heat conduction equation with apparent thermophysical properties to take the effect of blood perfusion into account. Feasibility was checked by comparing the results obtained from the heat conduction equation and the bioheat equation. The result indicated that the simulation with the apparent thermal conductivity or specific heat capacity does not agree well with the temperature distribution inside a tissue with blood perfusion. However, the apparent thermal conductivity was useful to estimate the size of growing ice ball produced during cryosurgery.

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Effect of blood flow and metabolism on multidimensional heat transfer during cryosurgery

Cited by 64 publications

References 39 publications

Comparative Analysis of Different Methods of Modeling the Thermal Effect of Circulating Blood Flow During RF Cardiac Ablation

Comparative Analysis of Different Methods of Modeling the Thermal Effect of Circulating Blood Flow During RF Cardiac Ablation

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

Feasibility of using apparent thermophysical properties to incorporate the effect of blood perfusion in estimation of temperature in tissues

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