Lee Jeong Min, Han Joon Koo, Choi Seung Hong, Kim Se Hyung, Lee Jae Young, Shin Kyung Sook, Han Chang Jin, Choi Byung Ihn
Department of Radiology and the Institute of Radiation Medicine, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-744, South Korea.
AJR Am J Roentgenol. 2005 Mar;184(3):897-905. doi: 10.2214/ajr.184.3.01840897.
We sought to determine whether hypertonic-saline (HS)-augmented bipolar radiofrequency ablation has advantages over monopolar radiofrequency ablation for creating larger areas of coagulation necrosis in the kidney.
Using a 200-W generator and bipolar perfused-cooled electrodes or a monopolar cooled-tip electrode, we performed 14 radiofrequency ablations in explanted bovine kidneys. Radiofrequency was applied in standard monopolar (n = 7) or bipolar (n = 7) modes at 100 W for 10 min. In the bipolar mode, the perfused-cooled electrodes were placed at interelectrode distances of 3 cm, and a 6% sodium chloride solution was instilled into tissue at a rate of 2 mL/min through the electrodes. For in vivo experiments, either monopolar (n = 7) or HS-augmented bipolar (n = 7) radiofrequency ablation was performed in the lower pole of canine kidneys. Three days after the procedure, contrast-enhanced CT scans were obtained to evaluate the volumes of the ablation regions, and the kidneys were harvested for gross measurements. Technical parameters such as changes in impedance and current during radiofrequency ablation and dimensions of the thermal ablation zones were compared between the two groups.
In ex vivo and in vivo experiments, the frequency of the pulsed radiofrequency application caused by rises in impedance was higher in the monopolar mode than in the bipolar mode during the application of radiofrequency energy. The in vivo study showed that the bipolar radiofrequency ablation allowed larger mean current flows than the monopolar radiofrequency ablation (i.e., mean +/- SD, 1,654 +/- 144 mA vs 967 +/- 597 mA) (p < 0.05). Ex vivo studies revealed that the volumes of bipolar radiofrequency-induced ablation regions were substantially larger than those of monopolar radiofrequency-induced ablation regions (26.1 +/- 10.5 cm(3) vs 10.2 +/- 4.2 cm(3)). In vivo studies showed bipolar radiofrequency ablation achieved larger coagulation necrosis than monopolar radiofrequency (3.2 +/- 0.3 cm vs 2.4 +/-0.4 cm) (p < 0.05). This was confirmed by the measured volume of nonenhancing area on contrast-enhanced CT (20.4 +/- 6.4 cm(3) vs 13.5 +/- 6.0 cm(3)).
HS-augmented bipolar radiofrequency ablation using perfused-cooled electrodes shows better performance in creating coagulation necrosis than monopolar radiofrequency ablation in the kidney of an animal model.
我们试图确定高渗盐水（HS）增强型双极射频消融在肾脏中形成更大面积的凝固性坏死方面是否比单极射频消融具有优势。
使用一台200瓦的发生器以及双极灌注冷却电极或单极冷却尖端电极，我们在离体牛肾中进行了14次射频消融。以标准单极（n = 7）或双极（n = 7）模式在100瓦下施加射频10分钟。在双极模式下，将灌注冷却电极放置在电极间距为3厘米处，并通过电极以2毫升/分钟的速率将6%的氯化钠溶液注入组织。对于体内实验，在犬肾下极进行单极（n = 7）或HS增强型双极（n = 7）射频消融。术后三天，进行对比增强CT扫描以评估消融区域的体积，并摘取肾脏进行大体测量。比较两组之间射频消融过程中的阻抗和电流变化等技术参数以及热消融区的尺寸。
在离体和体内实验中，在施加射频能量期间，单极模式下因阻抗升高导致的脉冲射频施加频率高于双极模式。体内研究表明，双极射频消融比单极射频消融允许更大的平均电流通过（即，平均值±标准差，1654±144毫安对967±597毫安）（p < 0.05）。离体研究显示，双极射频诱导的消融区域体积明显大于单极射频诱导的消融区域（26.1±10.5立方厘米对10.2±4.2立方厘米）。体内研究表明双极射频消融比单极射频消融实现了更大的凝固性坏死（3.2±0.3厘米对2.4±0.4厘米）（p < 0.05）。这通过对比增强CT上测量的无强化区域体积得到证实（20.4±6.4立方厘米对13.5±6.0立方厘米）。
在动物模型的肾脏中，使用灌注冷却电极的HS增强型双极射频消融在形成凝固性坏死方面比单极射频消融表现更好。
