Lee Jeong Min, Han Joon Koo, Kim Se Hyung, Sohn Kyu Li, Lee Kyoung Ho, Ah Su Kyung, Choi Byung Ihn
Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.
Korean J Radiol. 2003 Jul-Sep;4(3):163-9. doi: 10.3348/kjr.2003.4.3.163.
To compare the in-vitro efficiency of a hypertonic saline (HS)-enhanced bipolar radiofrequency (RF) system with monopolar RF applications by assessing the temperature profile and dimensions of RF-created coagulation necrosis in bovine liver.
A total of 27 ablations were performed in explanted bovine livers. After placement of two 16-gauge open-perfused electrodes at an interelectrode distance of 3 cm, 5% HS was instilled into tissue at a rate of 1 mL/min through the electrode. Seventeen thermal ablation zones were created in the monopolar mode (groups A, B), and ten more were created using the two open-perfused electrodes in the bipolar mode (group C). RF was applied to each electrode for 5 mins (for a total of 10 mins, group A) or 10 mins (for a total of 20 mins, group B) at 50W in the sequential monopolar mode, or to both electrodes for 10 min in the bipolar mode (group C). During RF instillation, we measured tissue temperature at the midpoint between the two electrodes. The dimensions of the thermal ablation zones and changes in impedance and wattage during RFA were compared between the groups.
With open-perfusion electrodes, the mean accumulated energy output value was lower in the bipolar mode (group C: 26675+/-3047 Watt s) than in the monopolar mode (group A: 28778+/-1300 Watt s) but the difference was not statistically significant (p > 0.05). In the bipolar mode, there were impedance rises of more than 700 ohm during RF energy application, but in the monopolar modes, impedance did not changed markedly. In the bipolar mode, however, the temperature at the mid-point between the two probes was higher (85 degrees C) than in the monopolar modes (65 degrees C, 80 degrees C for group A, B, respectively) (p < 0.05). In addition, in HS-enhanced bipolar RFA (group C), the shortest diameter at the midpoint between the two electrodes was greater than in either of the monopolar modes: 5.4+/-5.6 mm (group A); 28.8+/-8.2 mm (group B); 31.2+/-7.6 mm (group C) (p < 0.05)
Using an open perfusion system, HS-enhanced bipolar RFA more efficiently created larger areas of thermal ablation and higher tissue temperatures than monopolar RFA.
通过评估牛肝中射频产生的凝固性坏死的温度分布和尺寸，比较高渗盐水（HS）增强型双极射频（RF）系统与单极射频应用的体外效率。
在离体牛肝上共进行了27次消融。在将两个16号开放式灌注电极以3 cm的电极间距放置后，以1 mL/min的速率通过电极将5%的HS注入组织中。在单极模式下创建了17个热消融区（A组、B组），在双极模式下使用两个开放式灌注电极又创建了10个热消融区（C组）。在顺序单极模式下，以50W的功率对每个电极施加RF 5分钟（共10分钟，A组）或10分钟（共20分钟，B组），或在双极模式下对两个电极施加RF 10分钟（C组）。在RF注入过程中，我们在两个电极之间的中点测量组织温度。比较各组之间热消融区的尺寸以及RFA期间阻抗和功率的变化。
使用开放式灌注电极时，双极模式（C组：26675±3047瓦秒）的平均累积能量输出值低于单极模式（A组：28778±1300瓦秒），但差异无统计学意义（p>0.05）。在双极模式下，RF能量施加期间阻抗升高超过700欧姆，但在单极模式下，阻抗没有明显变化。然而，在双极模式下，两个探头之间中点的温度（85℃）高于单极模式（A组、B组分别为65℃、80℃）（p<0.05）。此外，在HS增强型双极RFA（C组）中，两个电极之间中点的最短直径大于任何一种单极模式：5.4±5.6 mm（A组）；28.8±8.2 mm（B组）；31.2±7.6 mm（C组）（p<0.05）
使用开放式灌注系统时，HS增强型双极RFA比单极RFA更有效地产生更大面积的热消融和更高的组织温度。
