Interventional Neuroradiology Research Laboratory, Research Center, Centre Hospitalier de l'Université de Montréal, Notre-Dame Hospital, 1560 Sherbrooke East Pavillon Simard, Ste Z12909, Montreal, Quebec, Canada.
J Vasc Interv Radiol. 2010 Jan;21(1):101-7. doi: 10.1016/j.jvir.2009.09.015. Epub 2009 Nov 27.
Coil embolization of intracranial aneurysms may be followed by recurrences. Radiofrequency (RF) ablation of the endothelium may prevent recanalization after coil embolization.
The authors performed in vitro experiments in chicken meat and egg white models to investigate the thermal distribution and geometry of lesions created with RF applied through standard coils alone or by using a prototype RF electrode inserted in a coil or a mass of coils. A mathematic model was designed to predict perianeurysmal isotherm lesions by using the bio-heat equation. In an in vivo coil arterial occlusion model (six dogs), the authors compared angiographic and pathologic results of coil embolization (n = 8) with those of coil embolization preceded by RF ablation (n = 7) by using a cardiac electrode at 1 month.
Current coils offer high impedance (400 Omega) at high current frequencies and are damaged by RF transmission. A dedicated electrode generated reproducible lesions, but contact with coils interferes with lesion reproducibility. When the coil mass was used, a uniform RF lesion that conformed to the coil mass shape was produced. The mathematic model predicted a uniform heat distribution within 1 mm from the coil mass periphery. Arterial coil embolization led to occlusion followed by recanalization (n = 8), whereas RF ablation (20-30 W for 60 seconds) prevented recanalization in all coil-occluded arteries (P < .001, chi(2) test). Pathologic findings helped confirm complete arterial occlusion with RF ablation. One animal developed brachial plexus injury with excessive levels of RF ablation.
RF ablation can prevent recanalization after coil occlusion-at least in the arterial model. Modifications of coils, dedicated neurovascular electrodes, and technique optimization remain necessary before considering a clinical application.
颅内动脉瘤的线圈栓塞后可能会复发。射频（RF）消融血管内皮可能会防止线圈栓塞后的再通。
作者在鸡肉和蛋清模型中进行了体外实验，以研究单独使用标准线圈或通过将原型 RF 电极插入线圈或线圈团中进行 RF 应用所产生的热分布和病变几何形状。设计了一个数学模型，通过生物热方程预测动脉瘤周围的等温线病变。在一个线圈动脉闭塞的体内模型（六只狗）中，作者在一个月时使用心脏电极比较了线圈栓塞（n = 8）和线圈栓塞前 RF 消融（n = 7）的血管造影和病理结果。
当前的线圈在高电流频率下提供高阻抗（400 欧姆），并且会受到 RF 传输的损坏。专用电极可产生可重复的病变，但与线圈接触会干扰病变的可重复性。当使用线圈团时，会产生与线圈团形状一致的均匀 RF 病变。数学模型预测线圈团周边 1 毫米范围内会产生均匀的热分布。动脉线圈栓塞导致闭塞后再通（n = 8），而 RF 消融（20-30 W 持续 60 秒）可防止所有线圈闭塞的动脉再通（P <.001，卡方检验）。病理发现有助于证实 RF 消融后的完全动脉闭塞。一只动物因 RF 消融过度而发生臂丛神经损伤。
RF 消融可以防止线圈闭塞后的再通-至少在动脉模型中是这样。在考虑临床应用之前，仍然需要对线圈、专用神经血管电极和技术优化进行改进。
