MRI在高强度聚焦超声消融子宫肌瘤中的应用进展

高强度聚焦超声（HIFU）已广泛应用于子宫肌瘤治疗,疗效确切。MRI软组织分辨率高,在妇科实体肿瘤检测中优势明显。MR多参数成像技术在术前拟定治疗计划、术中实时监测、术后疗效评估中具有不可替代的作用。本文对MRI各参数在HIFU消融子宫肌瘤术前、术中及术后的应用进行综述。     

子宫肌瘤超声消融后子宫浆肌层损伤早期MRI影像学特征及临床意义

目的探究子宫肌瘤超声消融后子宫浆肌层损伤早期MRI影像学特征及其临床意义。方法回顾性分析2019年9月~2020年9月在本院接受高强度聚焦超声（HIFU）消融术治疗的150例子宫肌瘤患者的临床资料,所有患者均于手术前后接受MR检查,影像学资料完整。比较手术前后患者的MRI信号改变情况,根据MRI图像特征确定术后患者子宫浆肌层损伤情况,将患者分为损伤组（n=43）和无损伤组（n=107）,观察损伤组患者的MRI形态特征,比较两组患者的超声消融情况及术后不良反应发生情况。结果术前,子宫肌瘤在T1WI上表现为低、等或高信号,在T2WI上表现为低或高低混杂信号、等信号或高信号,增强扫描均显示强化;术后肌瘤T1WI信号增高,T2WI信号变化无明显规律,增强扫描均显示无强化。超声消融后,子宫浆肌层损伤率为28.67%（43/150）,子宫浆肌层损伤的MRI表现为：T2WI序列显示肌瘤周边肌层信号连续,边界清晰;动态增强扫描显示子宫浆肌层呈环状强化,局部灌注缺损,前壁肌瘤的宫浆肌层损伤率最高为31.40%。损伤组的辐照时间、消融总剂量和肌瘤体积消融率均高于无损伤组（P < 0.05）,术后两组患者均出现一定不良反应,且损伤组患者阴道排液发生率高于无损伤组（P < 0.05）。结论子宫肌瘤患者接受HIFU消融术治疗后,早期会出现子宫浆肌层损伤,治疗期间的辐照时间长、消融总剂量及肌瘤体积消融率高会增加患者子宫浆肌层损伤的风险,使患者术后出现不良反应,通过MRI检查可有效评估患者的子宫浆肌层损伤情况。     

超声造影评价高强度聚焦超声消融治疗子宫肌瘤疗效的初步应用

目的探讨超声造影评价高强度聚焦超声治疗子宫肌瘤疗效的有效性。方法11例子宫肌瘤患者(12个病灶)分别在高强度聚焦超声治疗前3天、治疗后1个月、3个月及6个月采用常规二维超声、彩色多普勒超声及超声造影观察肌瘤大小、血流及造影改变。结果子宫肌瘤治疗后体积缩小明显,治疗后1个月、3个月及6个月体积缩小率分别为39．21±19．68%、55．58±25．69％、74．15±29．66％(P<0．05);肌瘤内部及周边的血流消失或基本消失:时间-强度曲线显示正常子宫肌层治疗前后造影剂灌注未见明显改变, 11个病灶治疗后呈持续造影剂无灌注或低灌注状态,余1个病灶边缘动脉期有小片状造影剂灌注。所有患者治疗后临床症状改善明显,少有并发症发生。结论超声造影是评价高强度聚焦超声治疗子宫肌瘤疗效的一种有效、简便的方法。     

磁共振成像在超声消融子宫肌瘤中的临床应用

随着当今社会人们生活水平的提高以及生物医学工程技术的飞速发展,新兴的微无创技术——高强度聚焦超声(HIFU)消融治疗正在成为广大子宫肌瘤患者的新选择。HIFU技术是从体外将超声能量聚集于治疗靶区使其温度瞬间升高至蛋白变性阈值温度,从而选择性灭活体内某特定区域病灶,并且对病灶周围及声通道上的组织结构无损害或损害很少。HIFU治疗子宫肌瘤具有疗效好、安全性高且并发症少等众多优点。MRI具有良好的软组织分辨力、无辐射,功能成像更能提供病灶分子水平的改变。因此,MRI已成为评价HIFU治疗子宫肌瘤疗效的重要手段。本文对MRI在HIFU治疗子宫肌瘤中的临床应用加以综述。     

超声消融治疗子宫肌瘤后早期疗效观察

目的 探讨高强度聚焦超声治疗子宫肌瘤患者的临床早期疗效和可行性.方法 高强度聚焦超声治疗38例临床症状明显的子宫肌瘤患者(43个肌瘤病灶),观察患者治疗前和治疗后1个月临床症状、血流情况、MRI平扫病灶体积大小等指标.结果 治疗后1个月,超声造影及MRI检查结果可见,42个肌瘤达到中度及显著灭活,病灶体积明显缩小,血供消失,1个肌瘤灭活不明显;两种检查方法比较,差异无统计学意义.所有患者均无并发症出现.结论 高强度聚焦超声治疗子宫肌瘤是有效和可行的,为临床非侵入性治疗子宫肌瘤提供了一种的新手段.     

高强度聚焦超声治疗子宫肌瘤二维超声疗效评价指标

目的 利用二维超声图像对HIFU治疗子宫肌瘤进行监控和疗效评价,探索建立二维超声半定量疗效评价的指标.方法 采用超声作为术中监控及疗效评价的影像学手段,把超声图像特点与MRI图像进行较分析,并根据不同声像图的子宫肌瘤对疗效的影响因素分析以及术中、术后超声变化情况,初步拟定二维超声疗效评分表对其进行评分与疗效等级结合,比较不同疗效等级间分值的差异并拟定治疗有效的分值.结果 有效和无效病例之间的分值有差异,分值≥22分可视为治疗有效.结论 通过评分表,超声可以较客观地评价疗效.     

多模态功能磁共振成像在高强度聚焦超声消融子宫肌瘤中的研究进展

子宫肌瘤是育龄期女性最常见的妇科良性肿瘤,高强度聚焦超声(high intensity focused ultrasound,HIFU)是治疗子宫肌瘤的一种非侵入性技术,依靠超声波的热能和机械能在监控影像的引导下消融靶组织,导致组织凝固性坏死。功能磁共振成像在评估HIFU消融子宫肌瘤的有效性和安全性中发挥了重要作用,能无创提供功能、灌注和代谢信息用于HIFU术前疗效预测、术后疗效评估及观察周围组织变化。本文就多模态功能磁共振成像在HIFU消融子宫肌瘤中的研究进展予以综述。     

US-MRI图像配准融合技术在高强度聚焦超声消融子宫肌瘤中的应用价值

目的 探讨超声和MRI图像（US-MRI）配准融合技术在高强度聚焦超声（HIFU）消融子宫肌瘤中的价值。方法 评估78例子宫肌瘤患者的80组US-MRI图像的配准与融合效果;记录并分析用于指导不同配准融合操作的解剖标记部位和效果。结果 以子宫的边界为标志配准同一子宫平面,与配准前比较,图像清晰度评分显著增加（P=0.004）;以子宫肌瘤的边界为标志配准同一子宫肌瘤平面,与配准前比较,图像清晰度评分显著增加（P<0.001）;以耻骨边界为标志能配准同一耻骨平面;以骶岬为标志点能配准骶尾骨。结论 US-MRI配准技术可有效提高HIFU消融子宫肌瘤的可视化空间。     

MRI在高强度聚焦超声消融治疗子宫内异位妊娠的应用价值

目的  探讨MRI在高强度聚焦超声消融(HIFU)治疗子宫内异位妊娠中的应用价值。方法  回顾性分析2016年12月~2021年12月在佛山市妇幼保健院经HIFU治疗的5例子宫内异位妊娠患者资料, 中位年龄35岁, 所有患者在术前及术后均行MRI检查。观察术前、术后MRI图像, 了解妊娠囊部位、大小、形态、生长方式、信号特点、妊娠囊附着处子宫肌层改变、强化及其HIFU术后MRI表现。结果  HIFU术前MRI示4例为瘢痕妊娠(CSP), 1例为宫颈妊娠; 2例妊娠囊信号均匀, 3例妊娠囊信号不均; CSP患者子宫前壁肌层明显变薄, 厚度1~2 mm。强化: 1例CSP患者妊娠囊未见强化, 但宫旁可见多发增粗、迂曲强化血管影; 余3例CSP患者妊娠囊内可见条索状、斑片状明显强化; 宫颈妊娠患者见妊娠囊壁均匀强化。HIFU术后MRI示: 4例妊娠囊均较前缩小, 1例妊娠囊较前无明显改变; 5例病灶信号均较前升高/不均匀; 1例CSP妊娠囊术前强化灶未见显示; 1例CSP患者术前无强化, 但术后宫旁增粗、迂曲强化血管较前减少, 强化程度减弱。另2例CSP妊娠囊仍见少许条索状、斑片状强化, 但强化范围较前缩小、部分坏死改变。宫颈妊娠患者妊娠囊壁未见强化。结论  MRI术前检查能明确妊娠囊位置及信号情况, 有助于HIFU术前准确定位, 且能显示妊娠囊与周围组织的关系; 术后动态增强扫描可判断HIFU治疗疗效。     

非灌注区域MR T2WI信号评估HIFU消融子宫肌瘤的疗效

目的 探讨MR增强非灌注区域T2WI信号在评估子宫肌瘤HIFU术后疗效中的价值。方法 收集因子宫肌瘤接受HIFU消融治疗,并于术前和术后第3天、3个月和6个月接受MRI随访的90例患者,根据术后第3天非灌注区域内T2WI信号不同,将其分为低信号组（n=9）、等信号组（n=15）、混杂信号组（n=40）和高信号组（n=26）,比较术后第3个月和6个月肌瘤残余体积的差异。结果 术后第3个月和第6个月,4组间肿瘤残余体积总体差异均有统计学意义（P均< 0.05）;两两比较,高信号组肌瘤残余体积均高于低信号组、等信号组和混杂信号组（P均< 0.05）;低信号组、等信号组和混杂信号组间差异均无统计学意义（P均>0.05）。术后患者未出现严重不良反应。结论 HIFU消融子宫肌瘤安全、有效;非灌注区域内T2WI信号可作为评估子宫肌瘤HIFU术后早期疗效的有效指标。     

MR增强扫描评估HIFU治疗原发骨肉瘤的短期疗效

目的 评估MR平扫和增强扫描在高强度聚焦超声(HIFU)治疗原发骨肉瘤短期疗效随访中的价值。 方法 回顾性分析11例原发骨肉瘤患者HIFU治疗前后的MR平扫和增强图像,观察病灶HIFU治疗前后的信号变化和强化特点。 结果 HIFU治疗前11例原发骨肉瘤T1WI以低信号为主、T2WI以高信号为主的混杂信号,增强扫描呈不同程度强化。HIFU治疗后病灶T1WI信号增高,T2WI信号减低;8例治疗1个月后病灶未见强化,其周围区域见条带样强化,3~4个月后呈线样强化;1例治疗1个月后在病变骨干内见片状强化;1例治疗1个月后在病灶边缘出现结节样强化,再次HIFU治疗后强化消失,病灶周围见条带状强化;1例治疗后与治疗前强化形式相似,再次HIFU治疗后病灶未见强化,周围出现线样强化带。 结论 MR增强扫描能准确评估原发骨肉瘤HIFU治疗后的短期疗效;根据常规MR平扫的信号改变不能准确判断肿瘤完全坏死或残留。     

动态增强磁共振成像定量参数对子宫肌瘤高强度聚焦超声治疗效果的即时评估价值初探

目的通过研究子宫肌瘤动态增强磁共振成像(dynamic contrast-enhanced MRI,DCE-MRI)定量参数与治疗效果的相关性,探讨定量参数对子宫肌瘤高强度聚焦超声(high intensity focused ultrasound,HIFU)治疗效果即时评估的应用价值。材料与方法回顾分析子宫肌瘤HIFU治疗的13个病例,根据治疗后DCE-MRI表现分为完全消融组及不完全消融组。应用Mann-Whitney U秩和检验和Spearman秩相关分析研究定量参数与分组的关联。结果 Ktrans(治疗后)、Ve(治疗后)、Vp(治疗后)与分组呈正相关,相关系数分别为r=0.713、0.757和0.668;Ktrans(变化率)、Ve(变化率)与分组呈负相关,相关系数均为r=-0.802,且相关性更显著。结论 DCE-MRI定量参数对子宫肌瘤HIFU治疗疗效即时评估具有参考价值。     

磁共振血氧水平依赖成像观察原发性肝细胞癌高强度聚焦超声治疗前后氧摄取变化特点

目的 通过观察原发性肝细胞癌(HCC)高强度聚焦超声(HIFU)治疗前后氧摄取变化特点,探讨BOLD MRI评估HIFU治疗原发性HCC疗效的潜在价值。方法 16例原发性HCC患者于HIFU治疗前及治疗后2周内接受常规MRI、BOLD MRI及动态增强扫描。BOLD MRI采用梯度回波序列。将BOLD图像数据传输至工作站,采用R2^*软件对图像进行后处理生成R2^*图及T2^*图。在病灶中心、周围正常肝组织以及背部肌肉设置ROI,测量R2^*值、T2^*值及信号强度(SI)。对3个ROI R2^*值、T2^*值及SI在HIFU治疗前后的差异进行比较。结果 与治疗前比较,HCC R2^*值在HIFU治疗后2周内明显升高 ,而T2^*值、SI值在HIFU治疗后2周内明显降低 。周围肝组织及背部肌肉R2^*值、T2^*值及SI值在HIFU治疗前后的无明显变化(P＞0.05)。结论 BOLD MRI在评价原发性肝细胞癌缺氧及HIFU疗效方面有一定潜力。     

基于质子共振频率MR温度成像监控高强度聚焦超声治疗

高强度聚焦超声（HIFU）作为一种热消融疗法,在治疗过程中需有良好的监控和实时精确的测温技术以保证治疗的安全性和有效性。MR温度成像通过具有温度敏感的参数进行测温,如弛豫时间、质子共振频率（PRF）、扩散系数、磁化矢量转移等,无创且无辐射,并可实时三维成像。其中,由于质子共振频率（PRF）对温度具有良好的线性度,且与组织类型不相关。基于PRF的MR温度成像成为中高场强（≥1T）系统应用的首选,在低场强系统中也有应用。本文对PRF MR温度成像的基本原理及其在监控HIFU治疗方面的研究进展进行综述。     

High-intensity focused ultrasound ablation of ex vivo bovine achilles tendon

Small tears in tendons are a common occurrence in athletes and others involved in strenuous physical activity. Natural healing in damaged tendons can result in disordered regrowth of the underlying collagen matrix of the tendon. These disordered regions are weaker than surrounding ordered regions of normal tendon and are prone to re-injury. Multiple cycles of injury and repair can lead to chronic tendinosis. Current treatment options either are invasive or are relatively ineffective in tendinosis without calcifications. High-intensity focused ultrasound (HIFU) has the potential to treat tendinosis noninvasively. HIFU ablation of tendons is based on a currently-used surgical analog, viz., needle tenotomy. This study tested the ability of HIFU beams to ablate bovine tendons ex vivo. Two ex vivo animal models were employed: a bare bovine Achilles tendon (deep digital flexor) on an acoustically absorbent rubber pad, and a layered model (chicken breast proximal, bovine Achilles tendon central and a glass plate distal to the transducer). The bare-tendon model enables examination of lesion formation under simple, ideal conditions; the layered model enables detection of possible damage to intervening soft tissue and consideration of the possibly confounding effects of distal bone. In both models, the tissues were degassed in normal phosphate-buffered saline. The bare tendon was brought to 23 degrees C or 37 degrees C before insonification; the layered model was brought to 37 degrees C before insonification. The annular array therapy transducer had an outer diameter of 33 mm, a focal length of 35 mm and a 14-mm diameter central hole to admit a confocal diagnostic transducer. The therapy transducer was excited with a continuous sinusoidal wave at 5.25 MHz to produce nominal in situ intensities from 0.23-2.6 kW/cm(2). Insonification times varied from 2-10 s. The focus was set over the range from the proximal tendon surface to 7 mm deep. The angle of incidence ranged from 0 degrees (normal to the tissue surface) to 15 degrees . After insonification, tendons were dissected and photographed, and the dimensions of the lesions were measured. Transmission electron micrographs were obtained from treated and untreated tissue regions. Insonification produced lesions that mimicked the shape of the focal region. When lesions were produced below the proximal tendon surface, no apparent damage to overlying soft tissue was apparent. The low intensities and short durations required for consistent lesion formation, and the relative insensitivity of ablation to small variations in the angle of incidence, highlight the potential of HIFU as a noninvasive treatment option for chronic tendinosis.     

高强度聚焦超声治疗肿瘤的MRI监控及疗效评价研究进展

高强度聚焦超声（HIFU）作为一种新的医疗技术为无创治疗带来了新的希望。医用磁共振成像技术（MRI）成像清晰,分辨率高,无电离辐射,可以监控靶区的温度变化,已被逐渐应用于HIFU治疗中。本文将对当前国内外有关HIFU治疗肿瘤的MRI监控和疗效评价的研究进展作一综述。     

High-intensity focused ultrasound tumor ablation activates autologous tumor-specific cytotoxic T lymphocytes

Previous studies have shown that high-intensity focused ultrasound (HIFU) ablation can enhance host antitumor immune response, though the mechanism is still unknown. In the present study, we investigated whether HIFU ablation could activate tumor-specific T lymphocytes and then induce antitumor cellular immunity. We studied 70 C57BL/6J mice bearing the H₂₂ tumor; they were randomly divided into a HIFU group and a sham-HIFU group. Of the mice, 35 in the HIFU group underwent HIFU ablation of the H₂₂ hepatic tumor, and the remaining 35 received a sham-HIFU procedure. In addition, 35 female, naïve syngeneic C57BL/6J mice were used as controls. All mice were sacrificed 14 days after HIFU, and the spleens were harvested. The function of T lymphocytes was determined. As a valuable tool for detecting and characterizing peptide-specific cells, the frequency of MHC class I tetramer/CD8-positive cells was quantified, which could help to determine the response and number of T lymphocytes. The therapeutic effect of the HIFU-activated lymphocytes on tumor-bearing mice was investigated after adoptive transfer of the lymphocytes. The results showed that compared to sham-HIFU and control groups, HIFU ablation significantly increased the cytotoxicity of cytotoxic T lymphocytes (p < 0.05), with a significant increase of IFN-γ and TNF-α secretion (p < 0.001). The frequency of the MHC class I tetramer/CD8-positive cells was significantly higher in the HIFU group (p < 0.05). A stronger inhibition of tumor progression and higher survival rates were observed to be significant after adoptive immunotherapy in the HIFU group as compared to the sham-HIFU and control groups (p < 0.01). It is concluded that HIFU ablation could activate tumor-specific T lymphocytes, thus inducing antitumor cellular immune responses in tumor-bearing mice.