Microwave ablation energy delivery: Influence of power pulsing on ablation results in an ex vivo and in vivo liver model
Microwave ablation energy delivery: Influence of power pulsing on ablation results in an ex vivo and in vivo liver model
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DOI：
10.1118/1.4901312
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发表时间：
2014-12-01
期刊：
影响因子：
3.8
通讯作者：
Brace, Christopher L.
中科院分区：
文献类型：
--
作者：
Bedoya, Mariajose;del Rio, Alejandro Munoz;Brace, Christopher L.
目的：本研究的目的是比较连续和脉冲能量传输对未灌注和灌注肝脏模型中微波消融生长和形状的影响。方法：使用五种传输方法之一（总共 50 例，每组 10 例），将 2.45 GHz 总共 15 kJ 的能量应用于离体牛肝脏：25 W 连续 10 分钟（平均 25 W），50 W 连续 5 分钟（50 W）平均）、100 W 连续 2.5 分钟（平均 100 W）、100 W 脉冲 10 分钟（平均 25 W）和 100 W 脉冲 5 分钟（平均 50 W）。使用与离体研究类似的递送方法将总共 30 kJ 施加到体内猪肝脏（n = 35，每组 7 个），但总消融时间是两倍，以抵消血液灌注的热量损失。在距消融天线 5-20 毫米处监测温度，温度超过 60 摄氏度表明发生急性细胞坏死。使用方差分析和事后配对测试，根据总能量传递、施加的平均功率和峰值功率，对实验组之间的消融大小和形状进行比较。结果：在离体组织中，脉冲组和连续组之间的消融大小或圆度没有显着差异。温度数据表明脉冲消融的加热速度更快，这表明脉冲可以克服血液灌注并在体内更快地凝固组织。尽管所有组之间的能量传递相同，但体内消融尺寸和形状存在差异。总体而言，体内最大消融体积是连续 5 分钟 100 W 产生的 (265.7 +/- 208.1 cm(3))。平均功率为 25 W 时，脉冲功率消融体积大于连续功率消融体积（67.4 +/- 34.5 cm(3) 对比 23.6 +/- 26.5 cm(3)，P = 0.43）。同样，脉冲消融产生的长度显着增加（P = 0.01），直径增加（P = 0.09），圆度略有下降（P = 0.97）。当比较 50 W 平均功率组时，注意到尺寸存在中等差异 (P >= 0.06)，并且脉冲消融再次稍微更圆。结论：与存在血液灌注的连续能量输送相比，脉冲能量输送在低平均功率下创建了更大的消融区域。较短的占空比似乎在脉冲时提供更大的好处。 (C) 2014 年美国医学物理学家协会。
Purpose: The purpose of this study was to compare the impact of continuous and pulsed energy deliveries on microwave ablation growth and shape in unperfused and perfused liver models.Methods: A total of 15 kJ at 2.45 GHz was applied to ex vivo bovine liver using one of five delivery methods (n = 50 total, 10 per group): 25 W continuous for 10 min (25 W average), 50 W continuous for 5 min (50 W average), 100 W continuous for 2.5 min (100 W average), 100 W pulsed for 10 min (25 W average), and 100 W pulsed for 5 min (50 W average). A total of 30 kJ was applied to in vivo porcine livers (n = 35, 7 per group) using delivery methods similar to the ex vivo study, but with twice the total ablation time to offset heat loss to blood perfusion. Temperatures were monitored 5-20 mm from the ablation antenna, with values over 60 degrees C indicating acute cellular necrosis. Comparisons of ablation size and shape were made between experimental groups based on total energy delivery, average power applied, and peak power using ANOVA with post-hoc pairwise tests.Results: No significant differences were noted in ablation sizes or circularities between pulsed and continuous groups in ex vivo tissue. Temperature data demonstrated more rapid heating in pulsed ablations, suggesting that pulsing may overcome blood perfusion and coagulate tissues more rapidly in vivo. Differences in ablation size and shape were noted in vivo despite equivalent energy delivery among all groups. Overall, the largest ablation volume in vivo was produced with 100 W continuous for 5 min (265.7 +/- 208.1 cm(3)). At 25 W average, pulsed-power ablation volumes were larger than continuous-power ablations (67.4 +/- 34.5 cm(3) versus 23.6 +/- 26.5 cm(3), P = 0.43). Similarly, pulsed ablations produced significantly greater length (P = 0.01), with increase in diameter (P = 0.09) and a slight decrease in circularity (P = 0.97). When comparing 50 W average power groups, moderate differences in size were noted (P >= 0.06) and pulsed ablations were again slightly more circular.Conclusions: Pulsed energy delivery created larger ablation zones at low average power compared to continuous energy delivery in the presence of blood perfusion. Shorter duty cycles appear to provide greater benefit when pulsing. (C) 2014 American Association of Physicists in Medicine.