Hines-Peralta Andrew, Hollander C Yehuda, Solazzo Stephanie, Horkan Clare, Liu Zheng-Jun, Goldberg S Nahum
Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 1 Deaconess Road, WCC 308B, Boston, Massachusetts 02215, USA.
J Vasc Interv Radiol. 2004 Oct;15(10):1111-20. doi: 10.1097/01.RVI.0000136031.91939.EC.
To determine whether the simultaneous application of combined bipolar radiofrequency (RF) ablation and cryoablation in a hybrid system produces larger ablation zones than RF or cryoablation alone.
Multiple 15-minute ablations were performed in ex vivo bovine liver (n = 167) with a hybrid applicator system with RF ablation alone (0.3-0.7 A), cryoablation alone (3,500 psi, two freeze/thaw cycles), and combined RF/cryoablation (0.4-0.7 A, 1,000-3,500 psi) with use of a novel applicator consisting of two 2.5-cm active bipolar RF poles located on the same 18-gauge needle separated by two embedded cryoablation nozzles. Resultant coagulation diameters were compared with use of analysis of variance for more than three groups or Student t tests for two groups. Confirmation of the optimal parameters of combination RF/cryoablation was performed by reassessing a range of argon pressure (1,000-3,500 psi) and RF current (0.4-0.7 A) in in vivo porcine liver (n = 36). Arrays of two to four RF/cryoablation applicators were also assessed in ex vivo (n = 54) and in vivo (n = 12) liver.
In ex vivo liver, simultaneous RF/cryoablation (0.6 A, 3,000 psi) produced 3.6 cm +/- 0.4 of short-axis coagulation. This was significantly larger than that achieved with optimal RF alone or cryoablation alone (1.5 cm +/- 0.3 and 1.6 cm +/- 0.3, respectively; F = 95; P < .01). The coagulation diameter with simultaneous combination RF/cryoablation was related in parabolic fashion to argon pressure and current with a multivariate r(2) of 0.68. For in vivo liver, optimal combination RF/cryoablation achieved 3.3 cm +/- 0.2 of coagulation, which was significantly larger than that achieved with RF alone (1.1 cm +/- 0.1; P < .01) or cryoablation alone (1.1 cm +/- 0.1 and 1.3 cm +/- 0.1; F = 203; P < .01). The greatest contiguous coagulation was achieved with multiple-applicator arrays. For ex vivo liver, short-axis coagulation measured 5.3 cm +/- 0.1, 6.4 cm +/- 0.1, and 7.6 cm +/- 0.1 for two-, three-, and four-applicator arrays, respectively. For in vivo liver, two-, three-, and four-applicator arrays produced 5.1 cm +/- 0.2, 5.8 cm +/- 0.5, and 7.0 cm +/- 0.5 of confluent coagulation, respectively.
Simultaneous combination RF and cryoablation with use of a novel applicator design yielded significantly larger zones of coagulation than either modality alone. The large ablation diameters achieved warrant further investigation of the device.
确定在混合系统中同时应用双极射频（RF）消融和冷冻消融是否比单独使用RF或冷冻消融产生更大的消融区。
使用一种新型的施加器，在离体牛肝（n = 167）中进行多次15分钟的消融，该施加器系统包括单独的RF消融（0.3 - 0.7 A）、单独的冷冻消融（3500 psi，两个冻融循环）以及联合RF/冷冻消融（0.4 - 0.7 A，1000 - 3500 psi），其中新型施加器由位于同一18号针上的两个2.5 cm有源双极RF电极组成，两个电极由两个嵌入式冷冻消融喷嘴隔开。使用方差分析（用于三组以上）或Student t检验（用于两组）比较所得的凝固直径。通过在活体猪肝（n = 36）中重新评估一系列氩气压力（1000 - 3500 psi）和RF电流（0.4 - 0.7 A），来确定联合RF/冷冻消融的最佳参数。还在离体（n = 54）和活体（n = 12）肝脏中评估了由两到四个RF/冷冻消融施加器组成的阵列。
在离体肝脏中，同时进行RF/冷冻消融（0.6 A，3000 psi）产生的短轴凝固直径为3.6 cm±0.4。这明显大于单独使用最佳RF消融或冷冻消融所达到的直径（分别为1.5 cm±0.3和1.6 cm±0.3；F = 95；P <.01）。同时进行联合RF/冷冻消融的凝固直径与氩气压力和电流呈抛物线关系，多变量r²为0.68。对于活体肝脏，最佳联合RF/冷冻消融实现的凝固直径为3.3 cm±0.2，这明显大于单独使用RF消融（1.1 cm±0.1；P <.01）或冷冻消融（1.1 cm±0.1和1.3 cm±0.1；F = 203；P <.01）所达到的直径。使用多个施加器阵列可实现最大的连续凝固。对于离体肝脏，两施加器、三施加器和四施加器阵列的短轴凝固直径分别为5.3 cm±0.1、6.4 cm±0.1和7.6 cm±0.1。对于活体肝脏，两施加器、三施加器和四施加器阵列分别产生5.1 cm±0.2、5.8 cm±0.5和7.0 cm±0.5的融合凝固。
使用新型施加器设计同时进行联合RF和冷冻消融产生的凝固区明显大于单独使用任何一种方式。所实现的大消融直径值得对该设备进行进一步研究。
