Radiofrequency ablation: Importance of background tissue electrical conductivity - An agar phantom and computer modeling study
Radiofrequency ablation: Importance of background tissue electrical conductivity - An agar phantom and computer modeling study
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DOI：
10.1148/radiol.2362040965
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发表时间：
2005-08-01
期刊：
影响因子：
19.7
通讯作者：
Goldberg, SN
中科院分区：
文献类型：
--
作者：
Solazzo, SA;Liu, ZJ;Goldberg, SN
目的：确定射频（RF）引起的加热是否可以在模拟不同背景组织电导率的受控实验模型环境中与背景电导率相关，并通过计算机建模确定这种相关性的潜在电气和物理基础。材料和方法：在由 80 个两室琼脂模型（内孔为 0.3%， 1.0% 或 36.0% 氯化钠），背景电导率变化范围为 0.6% 至 5.0% 氯化钠。对距电极 T-2cm 2 cm 处的电导率与温度之间的关系进行了数学建模。接下来，使用二维有限元分析 (ETherm) 对射频加热进行计算机模拟，并选择近似琼脂模型的参数。根据 T-2cm 和定义的热等温线与电极表面的距离计算所得的加热，并与模型数据进行比较。此外，使用计算机建模数据确定电和热分布，并使用线性回归分析进行关联。结果：对于每个内室 NaCl 浓度，增加的背景 NaCl 浓度与 T-2cm 之间建立负指数关系（R-2 = 0.64-0.78）。在计算机建模中观察到类似的负指数关系（r(2) > 0.97%）。对于0.3%、1.0%和36.0%内部氯化钠浓度，计算机和实验数据之间的相关值(R)分别为0.9、0.9和0.55。 RF电极周围产生的电场的绘图确定了在不同电背景2电导率的两个隔室之间的界面处发生的电场分布的显着局部变化(即，第二电峰值[“E-峰值”])的可能性。建立了 E 峰与 T-2cm（R-2 = 0.98-1.00）和 50 摄氏度等温线（R-2 = 0.99-1.00）加热之间的线性相关性。结论：这些结果证明了背景组织电导率与 RF 加热之间的密切关系，并进一步解释了两室系统中发生的电现象。 (c) 北美放射学会，2005 年。
PURPOSE: To determine whether radiofrequency (RF)-induced heating can be correlated with background electrical conductivity in a controlled experimental phantom environment mimicking different background tissue electrical conductivities and to determine the potential electrical and physical basis for such a correlation by using computer modeling.MATERIALS AND METHODS: The effect of background tissue electrical conductivity on RF-induced heating was studied in a controlled system of 80 two-compartment agar phantoms (with inner wells of 0.3%, 1.0%, or 36.0% NaCl) with background conductivity that varied from 0.6% to 5.0% NaCl. Mathematical modeling of the relationship between electrical conductivity and temperatures 2 cm from the electrode T-2cm was performed. Next, computer simulation of RF heating by using two-dimensional finite-element analysis (ETherm) was performed with parameters selected to approximate the agar phantoms. Resultant heating, in terms of both the T-2cm and the distance of defined thermal isotherms from the electrode surface, was calculated and compared with the phantom data. Additionally, electrical and thermal profiles were determined by using the computer modeling data and correlated by using linear regression analysis.RESULTS: For each inner compartment NaCl concentration, a negative exponential relationship was established between increased background NaCl concentration and the T-2cm (R-2 = 0.64-0.78). Similar negative exponential relationships (r(2) > 0.97%) were observed for the computer modeling. Correlation values (R) between the computer and experimental data were 0.9, 0.9, and 0.55 for the 0.3%, 1.0%, and 36.0% inner NaCl concentrations, respectively. Plotting of the electrical field generated around the RF electrode identified the potential for a dramatic local change in electrical field distribution (ie, a second electrical peak ["E-peak"]) occurring at the interface between the two compartments of varied electrical background 2 conductivity. Linear correlations between the E-peak and heating at T-2cm (R-2 = 0.98-1.00) and the 50 degrees C isotherm (R-2 = 0.99-1.00) were established.CONCLUSION: These results demonstrate the strong relationship between background tissue conductivity and RF heating and further explain electrical phenomena that occur in a two-compartment system. (c) RSNA, 2005.