微波消融活体家犬脑组织周围温度变化的实验研究

In vivo study of the temperature changes of brain tissue surrounding microwave ablation zone in a canine model

目的探讨脑组织微波消融的周围温度变化情况,为临床研究提供实验依据。方法以微波输出功率20 W、30 W及40 W消融12只家犬两侧脑组织180 s,记录微波消融过程中微波天线周围0.5 cm、1.0 cm、1.5 cm及2.0 cm处温度上升变化。术后1 h内行超声检查观察消融灶,并取标本观察病理改变。结果消融术后11只家犬观察期内基本状态良好,1只家犬于术后呼吸变深大并于2 h内死亡。消融过程中,距离消融中心0.5 cm处测温针温度升高迅速,20 W消融时最高温度为(96.40±1.46)℃;30 W及40 W消融时最高温度均达到100℃。距离消融天线中心1.0 cm处温度升高较快,最高温度均高于46℃。距离消融天线中心1.5 cm处温度升高较慢,20 W及30 W消融时最高温度低于46℃,40 W消融时最高温度高于46℃。距离消融中心2.0 cm处各功率消融时最高温度均低于46℃。距离消融灶中心1.0 cm、1.5 cm及2.0 cm处最高温度比较差异有统计学意义(F=776.78、2640.64和3025.53,P均<0.05)。消融灶长径、宽径及水肿宽度随消融功率增大而增大。功率为20 W、30 W及40 W消融灶长径分别为(29.3±1.8)mm、(32.7±2.1)mm和(34.2±2.4)mm;宽径分别为(22.5±1.5)mm、(23.7±1.7)mm和(27.1±2.0)mm;水肿带宽度分别为(2.3±0.4)mm、(2.6±0.4)mm和(2.7±0.5)mm。采用不同消融功率,消融灶长径及宽径间差异有统计学意义(F=11.46、14.49,P均<0.01),水肿带宽度的差异无统计学意义(F=1.94,P=0.169)。结论微波消融是一种对相对安全的介入治疗手段,距离消融中心距离越近,功率越大,消融灶越大,最高温度越高,且温度升高越快,距离消融中心2.0 cm处相对安全。

Objective To investigate the alteration of peripheral tissue＇s temperature of the coagulation zone of microwave ablation in brain tissue, and to provide experimental evidence for clinical application. Methods Twelve canines were treated by microwave ablation in brain tissue. Each was ablated for 180 s with microwave output power of 20 W, 30 W, and 40 W. During the operation the peripheral temperature at the distance of 0.5 cm, 1.0 cm, 1.5 cm and 2.0 cm from the ablation center was recorded respectively. The ultrasound was performed 1 hour after the operation, and then the animals were executed and the microscopic changes of the ablation lesion were observed. Results Eleven canines suffered well for the ablation, while 1 presemed abnormal respiration during the operation and died 2 hours later. During the operation, the temperature of the area 0.5 cm from the center rose significantly, with the maximum temperature was （96.40±1.46）℃ at the power of 20 W, and 100℃ at the power of 30 W and 40 W. The temperature of the area 1.0 cm from the center rose faster, with the maximum temperatures at different powers all above the 46℃. The temperature of the area 1.5 cm from the center rose slower, with the maximum temperature below 46℃ at the power of 20 W and 30 W and above 46℃ at the power of 40 W. The maximum temperatures of the area 2.0 cm from the center at different powers were all below 46℃. The difference of the maximum temperature at different distances （1.0 cm, 1.5 cm, and 2.0 cm from the center） was significant （F=776.78, 2640.64 and 3025.53, all P 〈 0.05）. The length and width of the ablation lesion as well as the area of edema increased with the power. At the power of 20 W, 30 W, and 40 W, the length of the ablation lesion was （29.3± 1.8） mm, （32.7±2.1） mm and （34.2±2.4） mm, the width was （22.5± 1.5） mm, （23.74±1.7） mm and （27.14±2.0） mm, and the width of the edema zone was （2.3±0.4） ram, （2.64±0.4） nun and （2.74±0.5） mm. The differences of the length and width of the ablation lesion at different powers were significant （F=11.46, 14.49, both P 〈 0.01）. The difference of the edema area at different powers was insignificant （F=1.94, .P=-0.169）. Conclusions Microwave ablation is a safe therapeutic modality. However, the shorter distance from the ablation center and greater ablation power give rise to larger ablation lesion, higher maximum temperature, and faster temperature increase. Therefore, 2.0 cm from the ablation center is a safe area.