聚焦超声增强聚桂醇消融兔肝的实验研究

目的 研究聚焦超声同步辐照对聚桂醇消融正常兔肝脏的增效作用。方法 健康新西兰大白兔26只随机分为三组：聚焦超声组（FUS组，6只）、聚桂醇组（LAU组，10只）及聚焦超声+聚桂醇组（FUS+LAU组，10只），分别给予聚焦超声辐照、聚桂醇及聚桂醇联合聚焦超声同步辐照处理。FUS焦点的平均声强（ISPTA）30.0W/cm2，工作占空比50%。48小时后观察处理区解剖及超声造影表现，测量血流充盈缺损区最大径。采用量筒法测定消融体积，消融灶HE染色后镜下观察组织学改变。采用Wilcoxon秩和检验比较LAU组与FUS+LAU组肝脏充盈缺损区最大径及消融体积的差异。结果 FUS组实验兔肝脏处理区未出现消融灶，LAU组与FUS+LAU组形成相似的黄白色消融灶。两组兔肝超声造影充盈缺损区平均最大径分别为(0.73±0.15)mm、(0.91±0.16)mm，差异有统计学意义(Z=-2.077，P=0.038)；两组平均消融体积分别为(0.19±0.06)ml、(0.47±0.20)ml，差异有显著统计学意义(Z=-3.182，P=0.001)，FUS+LAU组平均消融体积约为LAU组的2.5倍。两组消融灶HE染色均表现为典型的肝细胞坏死性改变。结论 聚焦超声同步辐照对聚桂醇消融正常兔肝有增效作用。     

超声空化促进乙醇消融兔肝脏的实验研究CSCD

目的研究低强度超声及微泡超声空化单独或联合应用对无水乙醇消融实验兔肝脏的增强效果,并观察此方法对实验兔肝脏血流灌注、肝功能的影响。方法健康新西兰大白兔62只,随机分为5组:低强度超声组(LUS组,6只),无水乙醇组(EA组,14只),低强度超声联合无水乙醇组(LUS+EA组,14只),微泡超声空化联合无水乙醇组(MEUS+EA组,14只),微泡超声空化联合低强度超声增强无水乙醇组(MEUS+LUS+EA组,14只)。按分组对经腹暴露的兔肝左叶分别给予处理,LUS组、MEUS+EA组及MEUS+LUS+EA组实验兔肝脏分别于超声辐照处理后,对处理叶及对照叶即刻进行超声造影并定量分析。EA组、LUS+EA组、MEUS+EA组、MEUS+LUS+EA组各取3只实验兔于实验前、实验结束后即刻、48 h、5 d及7 d抽取动脉血检测谷丙转氨酶(ALT)、谷草转氨酶(AST)浓度。余动物于实验结束后48 h分别获取肝脏组织,排液法测量肝脏消融体积,HE染色观察肝脏处理区域组织学改变。采用配对t检验比较各组实验兔肝脏处理叶与对照叶PI、AUC差异。采用Kruskal-Walis H秩和检验比较各组实验兔肝脏消融体积,进一步组间两两比较采用Nemenyi秩和检验。采用重复测量数据的方差分析比较各组实验兔肝脏AST浓度、ALT浓度随时间变化的趋势差异。结果 LUS组实验兔处理叶PI、AUC较对照叶稍高,但其差异均无统计学意义;MEUS+EA组、MEUS+LUS+EA组实验兔处理叶峰值强度(PI)、曲线下面积(AUC)均较对照叶降低(PI:51.65±16.90 vs 101.09±14.41,44.08±8.46 vs113.40±9.35;AUC:2183.06±501.13 vs 4258.54±841.21,1900.39±352.59 vs 4385.55±1198.16),且差异均有统计学意义(t=9.059、16.835、9.630、7.932,P均<0.001)。LUS组实验兔未见肝脏坏死灶,肝脏消融体积为0,EA组、LUS+EA组、MEUS+EA组、MEUS+LUS+EA组实验兔肝脏消融体积分别为(0.84±0.27)、(2.42±1.11)、(3.52±1.34)、(4.01±1.45)ml,EA组实验兔肝脏消融体积均低于其余3组,且差异均有统计学意义(U=-13.800、-20.400、-23.400,P均<0.05),而其余3组间任意2组实验兔间肝脏消融体积差异均无统计学意义。LUS组实验兔肝叶超声辐照区未见明显病理改变,其余4组均出现广泛凝固性坏死。与实验前相比,实验结束后即刻各组实验兔均出现肝脏ALT及AST浓度轻微升高,实验结束后48 h达最高,随后逐渐回落,实验结束后7 d,各组实验兔肝脏ALT、AST浓度基本恢复至实验前正常水平。4组实验兔肝脏AST浓度、ALT浓度随时间变化的趋势基本一致,差异无统计学意义(F=0.256,P=0.855;F=0.517,P=0.686)。结论低强度超声及微泡超声空化单独或联合作用均可显著增加无水乙醇消融兔肝脏体积,且不会导致肝功能损伤加重。     

超声空化促进乙醇消融兔肝脏的实验研究

目的研究低强度超声及微泡超声空化单独或联合应用对无水乙醇消融实验兔肝脏的增强效果,并观察此方法对实验兔肝脏血流灌注、肝功能的影响。方法健康新西兰大白兔62只,随机分为5组:低强度超声组(LUS组,6只),无水乙醇组(EA组,14只),低强度超声联合无水乙醇组(LUS+EA组,14只),微泡超声空化联合无水乙醇组(MEUS+EA组,14只),微泡超声空化联合低强度超声增强无水乙醇组(MEUS+LUS+EA组,14只)。按分组对经腹暴露的兔肝左叶分别给予处理,LUS组、MEUS+EA组及MEUS+LUS+EA组实验兔肝脏分别于超声辐照处理后,对处理叶及对照叶即刻进行超声造影并定量分析。EA组、LUS+EA组、MEUS+EA组、MEUS+LUS+EA组各取3只实验兔于实验前、实验结束后即刻、48 h、5 d及7 d抽取动脉血检测谷丙转氨酶(ALT)、谷草转氨酶(AST)浓度。余动物于实验结束后48 h分别获取肝脏组织,排液法测量肝脏消融体积,HE染色观察肝脏处理区域组织学改变。采用配对t检验比较各组实验兔肝脏处理叶与对照叶PI、AUC差异。采用Kruskal-Walis H秩和检验比较各组实验兔肝脏消融体积,进一步组间两两比较采用Nemenyi秩和检验。采用重复测量数据的方差分析比较各组实验兔肝脏AST浓度、ALT浓度随时间变化的趋势差异。结果 LUS组实验兔处理叶PI、AUC较对照叶稍高,但其差异均无统计学意义;MEUS+EA组、MEUS+LUS+EA组实验兔处理叶峰值强度(PI)、曲线下面积(AUC)均较对照叶降低(PI:51.65±16.90 vs 101.09±14.41,44.08±8.46 vs113.40±9.35;AUC:2183.06±501.13 vs 4258.54±841.21,1900.39±352.59 vs 4385.55±1198.16),且差异均有统计学意义(t=9.059、16.835、9.630、7.932,P均0.001)。LUS组实验兔未见肝脏坏死灶,肝脏消融体积为0,EA组、LUS+EA组、MEUS+EA组、MEUS+LUS+EA组实验兔肝脏消融体积分别为(0.84±0.27)、(2.42±1.11)、(3.52±1.34)、(4.01±1.45)ml,EA组实验兔肝脏消融体积均低于其余3组,且差异均有统计学意义(U=-13.800、-20.400、-23.400,P均0.05),而其余3组间任意2组实验兔间肝脏消融体积差异均无统计学意义。LUS组实验兔肝叶超声辐照区未见明显病理改变,其余4组均出现广泛凝固性坏死。与实验前相比,实验结束后即刻各组实验兔均出现肝脏ALT及AST浓度轻微升高,实验结束后48 h达最高,随后逐渐回落,实验结束后7 d,各组实验兔肝脏ALT、AST浓度基本恢复至实验前正常水平。4组实验兔肝脏AST浓度、ALT浓度随时间变化的趋势基本一致,差异无统计学意义(F=0.256,P=0.855;F=0.517,P=0.686)。结论低强度超声及微泡超声空化单独或联合作用均可显著增加无水乙醇消融兔肝脏体积,且不会导致肝功能损伤加重。     

聚焦超声增强聚桂醇消融正常兔肝的实验研究

目的探讨聚焦超声同步辐照对聚桂醇消融正常兔肝的增效作用。方法将健康新西兰大白兔26只随机分为聚焦超声组(6只)、聚桂醇组(10只)及聚焦超声+聚桂醇组(10只),分别给予聚焦超声辐照、聚桂醇及聚桂醇联合聚焦超声同步辐照处理。聚焦超声焦点的平均声强30.0 W/cm2,工作占空比50%。48 h后观察处理区形态学及超声造影表现,测量血流灌注缺损区最大径。采用量筒法测定消融体积;消融灶HE染色后镜下观察病理改变。比较聚桂醇组与聚焦超声+聚桂醇组肝脏灌注缺损区最大径及消融体积。结果聚焦超声组实验兔肝处理区未产生消融灶,消融体积为零。聚桂醇组与聚焦超声+聚桂醇组可见相似的黄白色消融灶,两组实验兔肝超声造影灌注缺损区平均最大径分别为(0.73±0.15)mm、(0.91±0.16)mm,差异有统计学意义(Z=-2.077,P=0.038);两组平均消融体积分别为(0.19±0.06)ml、(0.47±0.20)ml,差异有统计学意义(Z=-3.182,P=0.001),聚焦超声+聚桂醇组平均消融体积约为聚桂醇组的2.5倍。两组消融灶HE染色均表现为典型的肝细胞坏死性改变。结论聚焦超声同步辐照可增强聚桂醇对正常兔肝的消融作用。     

不同肝脏血流阻断方式对兔肝射频消融影响

目的 研究不同肝脏血流阻断方式对兔肝射频消融增强效果。方法 42只健康新西兰大白兔被平均分配到单纯消融组(NO组)、门静脉阻断联合射频消融组(PV组)、肝动脉门静脉全阻断联合射频消融组(HA+PV组)(n=14),射频系统采用RITA1500型冷循环射频消融仪,参数设定为15w、80℃、1min。按分组对各兔肝血管进行不同处理后,超声引导下进行射频消融。消融24h后超声造影测量消融灶各径线,取兔肝组织,对消融灶行大体测量,而后采用量筒排液法测量体积。各组另取3只实验兔分别于术前即刻、术后1、3、5、7日抽取兔肝动脉血检测ALT、AST、GGT、ALP。结果 1.三组间超声造影、大体标本测量消融灶范围均存在统计学差异,且HA+PV组消融灶最大。2.超声造影所测消融灶径线与大体标本相应测值比较未见明显统计学差异。3.三组实验兔ALT、AST均于术后第1日达到高峰,随后缓慢下降,术后7日基本恢复至术前即刻水平。各组间ALT、AST、ALP、GGT不同时间点变化趋势未见明显差异。结论 单独阻断门静脉血流或同时阻断门静脉、肝动脉血流均能有效增大射频消融灶各径线及体积,且全阻断效果最好。     

对比三维超声VOCAL技术与CT评估兔肝脏体积

目的对比评估三维超声VOCAL技术和CT测量兔肝脏体积的准确性。方法分别采用三维超声VOCAL技术和CT测量30只兔肝脏体积,将测量结果与采用水浸法测得的肝脏实际体积值进行比较。结果兔肝脏体积的三维超声VOCAL测量值、CT测量值与实际值间两两比较差异均无统计学意义(P均>0.05)。VOCAL法与CT法的测量误差分别为8.40%±4.40%及6.68%±4.45%(P>0.05)。三维超声VOCAL法测得的兔肝脏体积与实际值高度相关(r2=0.880,Y=9.146+0.826 X,P<0.001)。结论三维超声VOCAL技术可以准确测量兔肝脏体积,为评估不规则脏器体积提供了新的方法。     

超声评价微泡诱导超声空化联合血凝酶增强兔VX2肝癌微波热消融作用

目的 采用二维灰阶超声、CDFI和CEUS评价微泡诱导超声空化联合血凝酶对兔VX2肝癌微波热消融的增强作用。方法 将32只VX2肝癌荷瘤新西兰大白兔随机分为生理盐水组（空化假辐照+生理盐水）、血凝酶组（空化假辐照+生理盐水+血凝酶）、空化组（超声空化+微泡）和联合组（超声空化+微泡+血凝酶）4组,每组8只,分别给予相应空化治疗后行微波热消融治疗,并在治疗前后分别行二维灰阶超声、CDFI和CEUS检查,观察治疗前后超声表现,测量并比较肿瘤和消融区体积。结果 治疗前4组间肿瘤体积差异无统计学意义（P>0.05）,治疗后4组间消融区体积总体差异有统计学意义（P<0.001）;两两比较,联合组消融区体积大于其他3组（P均<0.05）,空化组消融区体积大于生理盐水组和血凝酶组（P均<0.05）,生理盐水组与血凝酶组体积差异无统计学意义（P>0.05）。治疗前肿瘤均可见丰富血流信号;消融后联合组肿瘤实质内CEUS均未显示增强,生理盐水组、血凝酶组和空化组部分肿瘤实质消融区边缘可见少量残余活性组织,呈典型"快进快出"表现,与CDFI显示的点状血流信号相对应。结论 微泡诱导超声空化联合血凝酶可增强兔VX2肝癌微波热消融效果。     

超声造影在兔肝纤维化实质灌注的定量评估

目的:采用实时灰阶超声造影定量分析纤维化兔肝的实质灌注情况。方法:对30例经硫代乙酰胺诱导的兔肝纤维化模型行超声造影定量分析,并将结果与病理对照。结果:造影灌注峰值强度随着兔肝纤维化程度(Sa～Sd)加重而逐渐减低,除Sb组与Sc组间峰值强度差异外,其余各组间差异均有统计学意义(P<0.05);而Sa组与Sb组及Sc组间的对比剂到达时间差异有统计学意义(P<0.05),且3组呈逐渐减低趋势;Sd组的达峰时间明显高于其余各组,且其与Sa组及Sc组间差异有统计学意义(P<0.05)。结论:通过实时灰阶超声造影可观察并评估肝纤维化程度。     

腹腔镜下人工胸、腹水在特殊部位肝癌热消融中的应用

目的观察腹腔镜下人工胸、腹水在特殊部位肝癌热消融中应用的效果。方法回顾性分析中山大学附属第三医院2003年6月至2007年5月收治的肝癌并进行热消融的患者131例,其中肝癌位于肝脏被膜下有47例,根据是否采用腹腔镜下人工腹水或胸、腹水辅助超声引导将患者分为A、B两组,A组25例,采用腹腔镜下人工腹水或胸、腹水辅助超声引导肝脏被膜下肿瘤消融;B组22例,仅采用超声引导经皮肝脏被膜下肿瘤消融。比较两组患者术后肝被膜下血肿、腹腔内出血、胸腔积液、肝脓肿和肝功能损害等并发症的发生率、肿瘤完全消融率及1年复发率。结果A组出现胸腔积液1例,肝功能损害2例,并发症发生率为12.0%;B组肝被膜下血肿2例,腹腔内出血1例,胸腔积液5例,肝功能损害1例,并发症发生率为40.9%。两组并发症的发生率差异有统计学意义（χ^2=5.144,P=0.023）。A组和B组肿瘤完全消融率分别为96.8%和72.4%,两组肿瘤完全消融率差异有统计学意义（χ^2=5.194,P=0.023）;1年复发率差异无统计学意义（P〉0.05）。结论腹腔镜下人工胸、腹水辅助超声引导肝脏被膜下肿瘤热消融,以人工胸、腹水为媒介,结合了热消融与腹腔镜两项微创技术的优点,有效地提高了热消融治疗肝癌的效果,减少了并发症的发生,扩大了热消融治疗的适应证。     

靶向性超声显影评价不同程度肝损伤的初步实验研究

目的 使用靶向超声分子显像对比分析大鼠不同程度急性肝损伤后峰值回声强度的改变与去唾液酸糖蛋白受体（ASGPR）的含量及血清学检查的关系.方法 根据腹腔灌注四氯化碳分析纯的不同剂量（10%、20%、30%、40%、50%）,将45只健康雄性SD大鼠随机分为相应5组（组Ⅰ~组Ⅴ）,每组9只,每组中再随机抽取4只取肝组织,分别检测ASGPR的含量;另5只仅常规麻醉,胸腹部备皮,经尾静脉团注靶向液态氟碳纳米脂质超声造影剂.从注射开始至0.5 h内连续观察并记录,0.5～1 h内每10 min观察并记录,1 h至造影剂消退每30 min观察并记录肝实质超声图像.DFY型超声图像定量分析诊断仪对各时间点采集到的超声图像进行分析.另选10只健康雄性SD大鼠作为靶向超声造影对照组,方法同前.结果 随着肝损伤程度的增加,肝组织内的ASGPR含量逐渐减少,且各组样本均数两两比较差异均有统计学意义（P〈0.05）.同时肝靶向超声造影后峰值回声强度逐渐降低,除对照组与组Ⅰ比较差异无统计学意义外,其余各组两两比较差异均有统计学意义（P〈0.05）,而达峰时间、峰值回声强度、造影前肝实质回声强度及清退后肝实质回声强度各组间比较差异均无统计学意义（P〉0.05）.结论 自制靶向肝实质细胞膜受体ASGPR的液态氟碳纳米超声造影剂的肝靶向性显影效果佳;不同程度肝损伤后的靶向超声显影结果改变与ASGPR结果改变一致,有利于超声显影定量评价肝脏功能.     

Impact of Microbubble-Enhanced Ultrasound on Liver Ethanol Ablation

Ethanol ablation (EA) is a safe and effective method for treating small liver cancer. However, the ethanol is rapidly washed out by blood perfusion, preventing its accumulation within tumors. Microbubble-enhanced ultrasound (MEUS) is capable of disrupting tumor and liver circulation. We hypothesized that this disruption could be used to enhance EA of normal liver tissue. We treated surgically exposed rabbit liver with a combination of MEUS and EA. The controls were treated with only MEUS or 0.05 mL EA. MEUS treatment was administered with a high-pressure-amplitude, pulsed therapeutic ultrasound device and intra-venous injection of microbubbles. Therapeutic ultrasound was delivered at an acoustic pressure of 4.3 MPa and a duty cycle of 0.22%. Contrast-enhanced ultrasound was performed to estimate liver blood perfusion. Livers were harvested for necrotic volume measurements 48 h after treatment. Contrast-enhanced ultrasound demonstrated that liver perfusion was temporally arrested, with a significant peak intensity decline from −46.9 ± 3.8 to −64.0 ± 3.3 dB, after MEUS treatment. The mean volume ablated in MEUS + EA-treated livers (3.3 ± 2.3 cm³) was more than 10 times larger than that in livers treated only with EA (0.3 ± 0.2 cm³). The volume of liver ablated by MEUS treatment alone was minor, scattered and immeasurable. These results indicate that MEUS disruption of the liver circulation can greatly promote EA of liver.     

Expression of Heat Shock Protein 70 in Rabbit Liver After Contrast-Enhanced Ultrasound and Radiofrequency Ablation

Heat shock proteins (HSPs) induced by thermal ablation therapy may help presenting tumor antigen to the host immune system and be a valuable adjuvant in the ablation therapy of liver cancer. This paper described our preliminary study on the expression of HSP70 in rabbit liver after contrast-enhanced ultrasound (CEUS) and radiofrequency (RF) ablation. Twenty-five male New Zealand white rabbits were divided into five groups as: control group (n=5), ultrasound group (n=5), CEUS group (n=5), RF group (n=5) and CEUS + RF group (n=5). Clinical ultrasound and RF ablation equipment were used in the present experiment. Sonazoid was used as the contrast agent. All the animals were sacrificed 24 h after the procedure, and HSP70 was detected by immunohistochemistry staining and Western blot analysis. In the groups without RF ablation, there was no evidence of HSP70 expression in the liver tissue of the control group and ultrasound group, whereas positive HSP70 expression was detected in the liver tissue of the CEUS group, with a mean optical density of 0.33. In the RF and CEUS + RF groups, there were cells showing HSP70 expression in the normal liver tissue far from the ablation region. The mean densities of HSP70 expression were 0.31 in the RF group and 0.35 in the CEUS + RF group, respectively. With regard to the distribution of HSP70 expression of the RF and CEUS + RF groups, the marginal areas were stronger than liver tissue 1 cm away from the margin, and the ablated tissues showed no evidence of HSP70 expression. The mean density of HSP70 expression in the marginal areas were 0.47 in the RF group and 0.42 in the CEUS + RF group, respectively. CEUS using Sonazoid may produce HSP70 expression in the normal liver parenchyma after CEUS examination and RF ablation. (E-mail: moriyasu@tokyo-med.ac.jp)     

微泡激励的超声空化阻断正常肝血流灌注的初步研究

目的探讨采用脉冲式超声激励微泡空化阻断兔正常肝脏血流的可行性及阻断的病理改变。方法健康新西兰大白兔24只随机分成3组,分别是超声微泡组、单纯超声组、假照组。经兔耳缘静脉注射脂质微泡,剂量0.1 ml/kg;同时超声治疗头垂直辐照兔肝脏300 s,超声能量以脉冲式发射,频率1.2 MHz,平均声强0.89 W/cm~2。靶区治疗前后进行超声造影检查和定量分析。最后,获取该区域肝组织标本,行病理学检查。结果超声微泡组治疗后肝组织血流灌注基本消失,而单纯超声组、假照组治疗前后无明显变化。超声微泡组治疗前后肝实质平均灰阶值(GSV)分别为115.27±3.8和1.16±0.7,治疗后肝实质GSV显著低于治疗前(P0.01),单纯超声及假照组治疗前后GSV无显著差别。病理检查,超声微泡治疗组肝组织出现大片充血、出血、血栓形成等。结论微泡增强的脉冲式超声空化可以造成正常肝的血流灌注暂时性阻断或者显著下降,阻断机制可能是肝实质出血、水肿和血栓形成。     

HIFU联合HL-1损伤正常兔肝脏组织的体内实验研究

目的　探讨一种脂质体 (HIFU L iposomes- 1,HL - 1)增强兔肝高强度聚焦超声 (high intensity focused ultrasound,HIFU )能量沉积和灰阶超声实时监控的效果。方法　将兔随机分为 A,B两组 ,A组右肝为实验侧 (HL - 1侧 ) ,左肝为生理盐水侧 ,B组相反。输入生理盐水后以一定参数行 A组左肝或 B组右肝 HIFU损伤 ;然后输入 HL - 1以相同参数行对侧组织 HIFU损伤 ;记录 HIFU靶区 B超灰度值。实验后 2 4h解剖 ,测量凝固性坏死组织大小、计算能效因子 (energy efficiency factor,EEF)并行组织病理检查。结果　灰度增强出现率在 A、 B两组的 HL - 1侧均有所增加 ,但差异无显著性 (P>0 .0 5 ) ;A,B两组 HL - 1侧的 EEF均明显低于对照侧 (P<0 .0 1) ;损伤组织大体观及病理检查两组两侧均为典型的凝固性坏死。结论　 HL - 1联合 HIFU能导致靶区组织发生凝固性坏死 ,并有增强正常兔肝脏组织 HIFU能量沉积的作用 ,灰阶超声对靶区组织凝固性坏死的实时监控作用有待进一步研究。     

体外治疗性超声辅助尿激酶溶栓的实验研究

目的评价体外治疗性超声（ＥＴＵＳ）辅助尿激酶（ＵＫ）溶栓的效果和安全性。方法选用日本大耳白兔,共２４只建成双侧股动脉血栓模型。随机分组接受不同方法（对照、ＥＴＵＳ、ＵＫ、ＥＴＵＳ＋ＵＫ）溶栓,超声频率０．８ＭＨｚ、声强１．２Ｗ／ｃｍ２、占空比１００％。ＵＫ分１５０００／ｋｇ与３００００μ／ｋｇ两种剂量,经耳缘静脉于３０ｍｉｎ内给入。结果单用ＥＴＵＳ组无明显溶栓,血管未出现再通。ＥＴＵＳ＋ＵＫ组与对应的ＵＫ组比较,溶栓量增加（Ｐ＜０．０１）,血管再通率提高（Ｐ＜０．０５）,血管再通所需时间缩短（Ｐ＜０．０１）。组织学检查显示ＥＴＵＳ应用组血管结构无损伤。结论０．８ＭＨｚ、１．２Ｗ／ｃｍ２连续波超声辅助ＵＫ溶解在体血栓安全有效     

Echo Decorrelation Imaging of Rabbit Liver and VX2 Tumor during In Vivo Ultrasound Ablation

In open surgical procedures, image-ablate ultrasound arrays performed thermal ablation and imaging on rabbit liver lobes with implanted VX2 tumor. Treatments included unfocused (bulk ultrasound ablation, N = 10) and focused (high-intensity focused ultrasound ablation, N = 13) exposure conditions. Echo decorrelation and integrated backscatter images were formed from pulse-echo data recorded during rest periods after each therapy pulse. Echo decorrelation images were corrected for artifacts using decorrelation measured prior to ablation. Ablation prediction performance was assessed using receiver operating characteristic curves. Results revealed significantly increased echo decorrelation and integrated backscatter in both ablated liver and ablated tumor relative to unablated tissue, with larger differences observed in liver than in tumor. For receiver operating characteristic curves computed from all ablation exposures, both echo decorrelation and integrated backscatter predicted liver and tumor ablation with statistically significant success, and echo decorrelation was significantly better as a predictor of liver ablation. These results indicate echo decorrelation imaging is a successful predictor of local thermal ablation in both normal liver and tumor tissue, with potential for real-time therapy monitoring.     

Effect of Microbubble-Enhanced Ultrasound on Radiofrequency Ablation of Rabbit Liver

Microbubble-enhanced ultrasound (MEUS) can non-invasively disrupt and block liver blood perfusion. It may potentially overcome the heat sink effect during a thermal ablation and consequently enhance radiofrequency ablation (RFA) of the liver. We propose a new strategy combining RFA with MEUS. For ultrasound treatment, an 831-kHz air-backed focused transducer directed 400-cycle bursts at 4.3?MPa to the liver at a 9-Hz rate. The treatment was nucleated by a lipids microbubble forming MEUS. Eighteen surgically exposed rabbit livers were treated using MEUS combined with RFA; the other 32 livers were treated using MEUS (n?=?14) or RFA (n?=?18) alone and served as the controls. Contrast ultrasound imaging confirmed that MEUS treatment significantly reduced liver blood perfusion by cutting contrast peak intensities in half (44.7%–54.1%) without severe liver function damage. The ablated liver volume treated using MEUS combined with RFA was 2.8 times greater than that treated using RFA alone. In conclusion, RFA of the liver can be safely and greatly enhanced by combination with MEUS pre-treatment.     

Transmission electron microscopy of rabbit liver after high-intensity focused ultrasound ablation combined with ultrasound contrast agents

The purpose of this study was to observe sequential changes in rabbit liver under transmission electron microscopy after high-intensity focused ultrasound (HIFU) ablation. Thirty rabbits were randomly divided into 2 groups. The livers of rabbits in group A underwent single HIFU ablation; those in group B were given the ultrasound contrast agent Sonovue 0.2 mL/kg before HIFU exposure. Five rabbits from each of the 2 groups were killed at 0 h, 6 d, and 14 d after HIFU ablation. Tissue samples that included targeted and untargeted tissues were observed under transmission electron microscopy. Electron microscopy showed that most of the cell organs in targeted areas of groups A and B disappeared early after HIFU, but the basic cell structure was seen in group A. On the sixth day after HIFU ablation in the 2 groups, all cells in the targeted areas were disrupted and fibrous bands were detected in the rims of targeted areas. In surrounding areas, cell swelling in group B was more severe than in group A, and a greater number of apoptotic bodies were found in group B. The use of an ultrasound contrast agent can enhance the effects of HIFU ablation on the destruction of cell ultrastructure and can enlarge the region of HIFU ablation; this provides experimental evidence for control of HIFU effects.     

HIFU联合脂质纳米氟碳液滴消融兔肝的实验研究

目的 探讨脂质纳米氟碳液滴增效HIFU消融兔肝脏的空化活动及术后病理学变化。方法 首先制备全氟戊烷脂质纳米氟碳液滴(L-PFP);然后将24只正常新西兰兔随机分为对照组(单纯HIFU组)和L-PFP组;在 B 超引导下进行HIFU定点消融兔肝脏(超声能量：900 J);通过被动空化检测系统(PCD)监控空化活动;分别将消融即刻、1d、3d、7d的兔肝脏标本取出进行H E染色,观察消融灶转归过程中的病理学变化。结果 经耳缘静脉注射L-PFP后HIFU 辐照兔肝脏所产生的空化泡群更明显,其灰度变化值为对照组的1.93倍,累积瞬态空化剂量为对照组的6.3倍,空化活动表现强烈;大体病理及H E结果显示L-PFP组造成的组织损伤严重,细胞变性更为彻底,炎性反应更为强烈;单纯HIFU组消融灶7d修复为正常组织,转归所需时间显著短于L-PFP组。结论 脂质纳米氟碳液滴通过增强空化效应有效提高HIFU消融效果,延长消融灶转归所需时间。