Thermochromic tissue-mimicking phantom for optimisation of thermal tumour ablation

Purpose The purpose of this study was to (1) develop a novel tissue-mimicking thermochromic (TMTC) phantom that permanently changes colour from white to magenta upon heating above ablative temperatures, and (2) assess its utility for specific applications in evaluating thermal therapy devices.

Materials and methods Polyacrylamide gel mixed with thermochromic ink was custom made to produce a TMTC phantom that changes its colour upon heating above biological ablative temperatures (> 60?°C). The thermal properties of the phantom were characterised, and compared to those of human tissue. In addition, utility of this phantom as a tool for the assessment of laser and microwave thermal ablation was examined.

Results The mass density, thermal conductivity, and thermal diffusivity of the TMTC phantom were measured as 1033?±?1.0?kg/m³, 0.590 ± 0.015 W/m.K, and 0.145?±?0.002?mm²/s, respectively, and found to be in agreement with reported values for human soft tissues. Heating the phantom with laser and microwave ablation devices produced clearly demarcated regions of permanent colour change geographically corresponding to regions with temperature elevations above 60?°C.

Conclusion The TMTC phantom provides direct visualisation of ablation dynamics, including ablation volume and geometry as well as peak absolute temperatures within the treated region post-ablation. This phantom can be specifically tailored for different thermal therapy modalities, such as radiofrequency, laser, microwave, or therapeutic ultrasound ablation. Such modality-specific phantoms may enable better quality assurance, device characterisation, and ablation parameter optimisation, or optimise the study of dynamic heating parameters integral to drug device combination therapies relying upon heat.     

Image-Guided High-Intensity Focused Ultrasound for Conduction Block of Peripheral Nerves

The objective of our work has been to investigate the use of ultrasound image-guided high-intensity focused ultrasound (HIFU) to non-invasively produce conduction block in rabbit sciatic nerves in vivo, a technique that could become a treatment of spasticity and pain. The work reported here involved the investigation of the duration of such conduction blocks after HIFU treatment and whether they resulted in axon degeneration. The right sciatic nerves of 12 rabbits were treated, under guidance of ultrasound imaging, with repeated 5-s applications of 3.2 MHz HIFU with in situ intensity of 1930 W/cm² (spatial-average, temporal-average) until conduction block was achieved. Survival endpoints were 0, 7, or 14 days after HIFU treatment, at which point the nerve conduction was assessed. Qualitative and quantitative histological analysis of nerve sections proximal and distal to the HIFU site was performed. Conduction block of all 12 nerves was achieved with average HIFU treatment time of 10.5±4.9 s (mean±SD). The volume of necrosis of adjacent muscle was measured to be 1.59±1.1 cm³ (mean±SD). For all nerves, conduction block remained at the survival endpoint and the block resulted in degeneration of axons distal to the HIFU site, as confirmed by electrophysiological and histological methods. Potential clinical applications include treatment of spasticity in patients with spinal cord injury or pain in cancer patients.     

动态超声造影监测高强度聚焦超声治疗腹部恶性肿瘤疗效的临床价值

 目的 通过比较腹部恶性肿瘤在高强度聚焦超声（high-intensity focused ultrasound,HIFU）治疗前后的动态超声造影（dynamic contrast enhanced ultrasound,DCEUS）定量分析曲线及灌注参数,探讨DCEUS技术在HIFU治疗腹部恶性肿瘤疗效随访中的临床应用价值。方法 从2018年9月到2021年5月,前瞻性地纳入计划接受HIFU治疗的腹部恶性肿瘤患者,所有的病灶经穿刺或手术病理证实,且临床诊断为晚期恶性肿瘤。在HIFU开始治疗前1天及4周后分别进行超声造影（contrast enhanced ultrasound,CEUS）检查。Vuebox图像分析软件分析CEUS检查过程并生成时间-强度曲线（time intensity curve,TIC）,并得到定量参数,包括峰值强度（peak enhancement,PE）、上升时间（rise time,RT）、达峰时间（time to peak,TTP）、平均渡越时间（mean transit time, mTT）及曲线下面积（area under curve,AUC）。比较HIFU治疗前后腹部恶性肿瘤病灶大小、CEUS增强-消退表现、TIC曲线、定量参数及肿瘤标志物的差异。结果 本研究最终纳入患者共19例。HIFU治疗前后,患者肿瘤标记物及病灶大小及CEUS表现均无明显变化。DCEUS分析结果显示,相较于HIFU治疗前,HIFU治疗后肿瘤病灶的TIC曲线峰值强度降低、曲线下面积缩小。在所有DCEUS定量参数中,PE ［（32 920.63±24 822.71）a.uvs. （17 296.11±16 570.41） a.u,P=0.001］及AUC［（624 665.28±593 711.71） a.u vs. （309 148.00±366 938.07） a.u,P=0.002］均显著低于治疗前。结论 DCEUS可在评估HIFU治疗腹部恶性肿瘤疗效时监测病灶微循环血流灌注,定量参数PE及AUC是具有潜在意义的评估参数。     

高强度聚焦超声治疗及控制兔肝VX2肿瘤发展的实验研究

目的 探讨高强度聚焦超声(HIFU)治疗及控制肝肿瘤发展转移的效果.方法 采用兔肝VX2肿瘤模型进行HIFU辐照.辐照后不同时期处死动物以观察其病理变化.另以辐照组及对照组动物各8只,于2周后处死,比较肿瘤生长及肺转移的情况.结果 HIFU辐照后肿瘤细胞立即发生凝固性坏死,电镜下亦见到不可逆的破坏.2周后有6只动物的肿瘤原发灶已被完全破坏;另2只靶区外有少量肿瘤残存,其体积为59.8 mm3和10.4mm3,而对照组的肿瘤平均体积为(1571.1±349.7)mm3.辐照组有2只(25%)发生肺转移,转移结节数为10和3;对照组全部发生肺转移,转移结节数为54±30.两组差异有显著性.结论 HIFU对兔肝VX2肿瘤有很强的杀伤作用,对控制肿瘤的发展及转移有一定的疗效.     

肝动脉置管栓塞在高强度聚焦超声(HIFU)治疗肝癌中的作用

目的 探讨肝动脉置管栓塞在高强度聚焦超声治疗肝癌中的作用。方法 利用高强度聚焦超声(HIFU)治疗44例肝癌患者。对12例HIFU治疗前需肋骨开窗的病人，在开窗的同时给予肝动脉置管栓塞，观察其在此方治疗中的利弊。结果 此法为肝癌HIFU治疗中需开窗的病人争取了时问，节约了费用，为进一步追加治疗提供了方便。结论 肝癌HIFU治疗中需开窗的病人在肋骨切除术中给予肝动脉置管栓塞是可行的。     

高强度聚焦超声治疗前列腺增生症的新探索

目的 探索采用大功率、短脉冲、经会阴入射HIFU治疗前列腺增生症（BPH）的有效性和安全性。 方法 22例BPH患者采用大功率、短脉冲、经会阴入射HIFU进行治疗，治疗后1周、1个月、3个月通过I-PSS评分、尿流率、残余尿、前列腺体积变化进行近期疗效判断。 结果 治疗后1周、1个月、3个月I-PSS评分明显降低，有效率为90．9％，治疗后1周、1个月、3个月最大尿流率和平均尿流率均明显升高，残余尿量减少，而前列腺体积缩小不明显。 结论 采用大功率、短脉冲、经会阴入射HIFU治疗BPH具有无痛苦、不用麻醉、无烧伤、无需留置尿管、不住院等优点，近期疗效满意，其远期疗效、作用机理及影响疗效的因素还有待进一步观察和深入研究。     

HL-1改变兔肝脏组织声学环境的实验研究(Ⅰ)

目的　探讨HL -1改变兔肝脏组织声学环境的作用及机制。方法　实验组经兔耳缘静脉输入HL -1,B超实时监测 0min ,2min ,5min ,10min ,15min和 2 0min兔肝脏的声像图。对照组以生理盐水代替HL -1,余步聚同实验组。实验后两组兔肝脏送组织病理检查。结果　实验组兔肝脏BUGs随HL -1的输入而迅速下降 ,至 15～ 2 0min时达最低值 ( -12 .90± 2 .5 3 ) ;对照组稍有增加 ( 1.43± 1.90 )。大体观实验组兔肝脏呈粉红色 ,可见类似脂肪肝似的脂质沉着 ;病理检查肝细胞增大、肿胀、肝索排列紊乱 ,肝血窦腔隙及中央静脉缩小 ,肝细胞及肝血窦内见大量脂质体沉积 ,位于血窦的脂质体有聚积现象 ,与对照组肝脏有明显差异。结论　静脉快速输入HL -1可使兔肝脏组织结构发生相应的变化 ,使肝脏声吸收衰减增加 ,因而改变了肝脏组织声学环境     

Clinical utility of a microbubble-enhancing contrast (“SonoVue”) in treatment of uterine fibroids with high intensity focused ultrasound: A retrospective study

Purpose

To evaluate the clinical value of the contrast agent SonoVue in the treatment of uterine fibroids with ultrasound-guided high intensity focused ultrasound (HIFU) therapeutic ablation.

Materials and Methods

A total of 291 patients with solitary uterine fibroid from three centers were treated with ultrasound-guided HIFU. Among them, 129 patients from Suining Central Hospital of Sichuan were treated without using SonoVue. 162 patients from the First Hospital of Chongqing Medical University and Chongqing Haifu Hospital were treated with using SonoVue before, during and after HIFU procedure to assess the extent of HIFU.

Results

The non-perfused volume (indicative of successful ablation) was observed in all treated uterine fibroids immediately after HIFU ablation; median fractional ablation, defined as non-perfused volume divided by the fibroid volume immediately after HIFU treatment, was 86.0% (range, 28.8–100.0%) in the group with using SonoVue, and 83.0% (8.7–100.0%) without SonoVue. The rate of massive gray scale changes was higher with SonoVue than without the agent. The sonication time to achieve massive gray scale changes was shorter with SonoVue than without. The sonication time for ablating 1 cm³ of fibroid volume was significantly shorter with using SonoVue than without. No major complications were observed in any patients.

Conclusions

Based on our results, SonoVue may enhance the outcome of HIFU ablation and can be used to assess the extent of treatment.     

高能聚焦超声热疗合并奥曲肽治疗晚期胰腺癌的随机临床对照研究

目的评价HIFU联合奥曲肽治疗晚期胰腺癌的近期疗效与不良反应的观察。方法病理确诊的晚期胰腺癌患者46例(有可测量病灶者),随机分为热疗组和联合组,联合组采用FBY01北大研制的高强度聚焦超声联合奥曲肽治疗,两组均至少治疗2周期后评价疗效。结果全组均可评价疗效。联合组临床受益反应率为75.0%(18/24),热疗组为36.4%(8/22),2组比较有非常显著差异(P<0.01)。联合组治疗前后及两对照组治疗后比较,都有非常显著差异(P<0.01)。热疗组中位生存期约8.8月,联合组中位生存期达到10.8个月,P>0.05。两组的近期有效率,中位生存时间无显著差异(P>0.05)。毒副作用轻微,二者无显著性差异。结论HIFU联合奥曲肽治疗晚期胰腺癌临床受益反应率改善明显,VEGF水平下降明显,且毒副反应轻,病人能耐受,值得临床推广应用。