纳米级脂质微泡的制备及其在动脉血栓检测中的应用

目的:制备一种纳米级脂质超声微泡造影剂,观察其物理性质及稳定性,并将其运用于兔颈总动脉血栓模型,以评价其显影效果.方法:采用薄膜-水化法制备纳米级脂质微泡,分别于第1天、7天于显微镜下观察微泡形态, 测量微泡粒径、表面电位,微泡浓度、物理特性.建立兔颈动脉血栓模型,分别于建模前及建模后经兔耳缘静脉团注自制纳米级脂质微泡, 动态观察建模前及建模后兔颈动脉回声增强效果.结果:①显微镜下观察微泡呈球形,大小均匀,分散度良好;第1天纳米级脂质微泡平均浓度为5.0×10~(10)个/ml,微泡粒径中位数为794.5 nm,微泡粒径范围为(794.5±123.6)nm,表面电位为-9.831 mV;第7天纳米脂质体微泡平均浓度为1.08×10~(10)个/ml,微泡粒径中位数为970.8 nm,微泡粒径范围为(970.8±122.5)nm,表面电位为-10.83 mV.②兔颈动脉造影效果:自制纳米级脂质微泡于兔颈动脉血栓建模型前、后均能明显增加兔颈总动脉显像.结论:自制纳米级脂质微泡形态好,粒径均一,显影效果理想,为纳米颈总动脉血栓靶向性显像研究提供了研究基础.     

反义寡核苷酸并超声微泡造影剂转染联合超声照射逆转肝癌多药耐药

目的探讨体内、体外mdr1、mrp、lrp反义寡核苷酸(AODNs)并超声微泡造影剂转染联合低强度超声照射逆转肝癌多药耐药的可行性,寻找逆转肿瘤多药耐药有效和靶向的方法。方法利用超声微泡造影剂包载肿瘤耐药基因mdr1、mrp、lrp的AODNs进行转染,联合低强度超声照射,以肝癌细胞多药耐药细胞模型(HepG2／ADM) 为研究对象,通过逆转录聚合酶链反应、western blot和四甲基偶氮唑盐法,从体外细胞培养及动物实验,研究 AODNs并超声微泡造影剂转染联合超声照射逆转癌细胞多药耐药及降低肿瘤恶性表型和成瘤能力的作用。结果 HepG2／AMD细胞增殖被抑制,其mdr1和mrp的mRNA、蛋白质表达水平明显降低;裸鼠皮下移植瘤生长受抑制。结论体外、体内AODNs并超声微泡造影剂转染联合低强度超声照射能有效逆转人肝癌细胞HepG2／ADM的多药耐药, 该技术可能为肝癌临床治疗提供新的思路。     

^131I-AFP单克隆抗体联合低频超声辐射微泡剂治疗小鼠heps肝癌的实验研究

目的观察^131I-AFP单克隆抗体联合低频超声辐射微泡剂治疗小鼠heps肝癌的疗效。方法30只小鼠建立heps肝癌移植瘤模型后随机分为4组：对照组（不做治疗）、单纯超声微泡组、单纯^131I-AFP单克隆抗体组、超声微泡联合^131I-AFP单克隆抗体组。治疗2周内连续观察各组肿瘤体积变化,行ECT显像并做肿瘤局部的放射性计数,流式细胞仪测定细胞周期变化及细胞凋亡情况。结果单纯超声微泡组、单纯^131I-AFP单克隆抗体组、超声微泡联合^131I-AFP单克隆抗体组肿瘤体积明显小于对照组（P均〈0．05）,超声微泡联合^131I-AFP单克隆抗体组放射性计数的衰减率明显低于单纯^131I-AFP单克隆抗体组,并且能提高靶/非靶值。结论^131I-AFP单克隆抗体联合低频超声辐射微泡剂是肿瘤治疗的新方法,无创、安全、有效。     

脉冲超声联合微泡对兔肿瘤血管的调节作用

目的 研究超声联合微泡治疗是否可以短暂增加肿瘤的微循环血流灌注，并增强肿瘤化疗效果。方法 将66只新西兰荷瘤兔随机分为超声微泡阿霉素组、超声微泡组、超声组、微泡组、阿霉素组及对照组，每组各11只。予实验组静脉注射阿霉素后，即刻予超声微泡治疗；通过肿瘤血流灌注的评估、肿瘤微血管形态观察、肿瘤体积监测等开展实验。结果 超声微泡阿霉素组及超声微泡阿霉素组，肿瘤血流灌注的受试者工作特征曲线下面积(AUC)值在治疗后显著提高(P<0.01,P<0.05)。超声微泡组肿瘤微血管周围有高密度的阿霉素分布。结论 脉冲超声联合微泡可以短暂增加肿瘤的微循环血流灌注，并提高化疗药的转运。     

载紫杉醇超声微泡造影剂对人肝癌HepG2细胞周期及形态的影响

目的 探讨超声辐照紫杉醇微泡造影剂,对人肝癌细胞株HepG2细胞周期的影响和形态学变化.方法 体外培养人肝癌HepG2细胞,将细胞分4组,即空白对照组,紫杉醇组,超声空白微泡组,超声载紫杉醇微泡组.流式细胞仪检测不同处理组细胞周期分布,透射电镜观察不同处理组形态学变化. 结果 超声载紫杉醇微泡组细胞阻滞在G2/M期;超声载紫杉醇微泡能够诱导肿瘤细胞发生凋亡,并有凋亡小体形成.结论 超声辐照载紫杉醇微泡造影剂对人肝癌细胞株HepG2有明显阻滞作用,并诱导肿瘤细胞发生凋亡.     

经静脉声学造影重建兔VX2肝癌的三维图象

目的对肝脏实质性肿瘤进行重建观察是三维超声的一个难点.我们应用经静脉注射新型声学造影剂结合三维超声成象重建肝脏肿瘤的三维图象.方法制作兔VX2肝癌模型13只.静脉注射新型声学造影剂FX530后,以间断观察法观察并采集图象.三维重建方法:①Echo-Scan三维工作站与Sonos 5500彩超仪配合使用,彩色多普勒能量图观察,利用声学造影产生的"彩色花簇”现象对肿瘤以最大回声模式进行重建;②利用造影后肿瘤显示为相对弱回声以最小回声模式三维重建肿瘤的组织灰阶图象.结果造影前肿瘤为近等回声,不适于三维重建观察.造影后,方法①:显示VX2肝癌呈"球形的空洞”,从球体形肿瘤空洞内部观察显示,肿瘤边缘轮廓清晰完整,表面特征明显,显示肿瘤立体感强.方法②:观察时,造影后肿瘤呈负性显影(弱回声),肿瘤边界轮廓清晰可辩,三维重建后可观察肿瘤的立体形态,并测量肿瘤的体积.结论应用新型声学造影剂FX530和三维超声成象技术可良好地重建肝癌的三维图象,为超声观察肝脏肿瘤提供了新的途径.     

经静脉心肌声学造影剂的研制

目的 :制备可经静脉注射产生心肌对比增强效果的声学对比造影剂 ,观察其心肌显影效果。方法 :1按不同比例将 5 0 g· L- 1 葡萄糖或 9g· L- 1 Na Cl,C3 F8气体与人血白蛋白混合后进行超声振荡。 Coulter’ s计数器对造影剂进行质量分析。 2经犬股静脉注射自制对比造影剂 0 .2 ml,经胸壁扫查犬左室乳头肌水平短轴切面。结果 :1造影剂微泡液的相对浓度为 4 .2 3 9× 10 9/m l,微泡平均直径 3 .789μm,小于 9.89μm微泡占 99.5 %。 2经静脉注射后 ,均产生不同程度的心肌对比增强效果 ,心肌显影持续时间 1～ 3 min。注射前后犬血流动力学无显著性改变。结论 :自制经静脉注射对比造影剂符合心肌声学造影的要求 ;初步动物实验表明经静脉注射可产生肉眼可辨的心肌显影 ;反复注射无明显血流动力学改变     

沉默单酰基甘油脂肪酶mRNA对肝癌大鼠的作用及机制

目的研究沉默单酰基甘油脂肪酶(MAGL)mRNA对大鼠肝癌的作用及其机制。方法 CBRH7919大鼠肝癌细胞原位移植法建立大鼠肝癌模型,建模后免疫组化检测肝癌组织及正常肝组织甲胎蛋白(AFP)表达。分为PBS液组;MAGL-shRNA质粒微泡组;空白微泡+超声辐照组;MAGL-shRNA质粒微泡+超声辐照组(A);MAGL-shRNA质粒微泡+超声辐照组(B);MAGL-shRNA质粒微泡+超声辐照组(C)。每只大鼠经尾静脉注射1 ml相应试剂,并对空白微泡+超声辐照组和MAGL-shRNA质粒微泡+超声辐照A、B、C组的大鼠肝区给予超声辐照。前4组:免疫印迹检测大鼠肝癌组织MAGL表达,荧光定量PCR检测MAGL mRNA表达情况,ELISA检测癌组织游离脂肪酸(FFAs)。解剖并比较各组大鼠的肿瘤大小、转移情况。B组给予高脂饮食1 w后与C组一同处死,比较其肿瘤组织MAGL表达情况、FFAs含量以及肿瘤大小。结果肿瘤病理检测符合原发性肝癌。前四组:免疫印迹检测显示,MAGL-shRNA质粒微泡+超声辐照组A的MAGL蛋白表达趋势明显降低;PCR结果显示,该组MAGL-mRNA明显低于其他3组(P0.05);ELISA显示该组FFAs含量明显低于其余各组(P0.05);该组肿瘤平均大小及转移率明显小于其余三组(P0.05)。后两组:高脂饮食组癌组织MAGL蛋白表达、FFAs浓度明显高于正常饮食组,且前者肿瘤明显大于后者(P0.05)。结论沉默MAGL mRNA能够明显抑制大鼠肝癌生长;高脂饮食能够逆转MAGL沉默基因的治疗作用;MAGL作用机制可能是通过调控FFAs及下游因子实现。     

实时超声造影技术对VX2兔肝癌影像学模型的诊断价值

目的:评价实时超声造影技术对VX2兔肝癌影像学模型的诊断价值.方法:25只肝脏种植VX2移植瘤的新西兰大白兔于种植后第21天行彩色多普勒超声检查,并经耳缘静脉团注造影剂SonoVue,行实时超声造影检查,观察肿瘤及其周边正常肝组织动态超声增强表现.结果:20只(80%)大白兔种植成功.在二维超声上,肿瘤为类圆形等回声肿块,周边可见声晕,部分中心可见低回声坏死区.彩色多普勒血流显像(CDFI)能探测到肿瘤周边或内部点、条状血流信号.注入造影剂后,动脉相见肿瘤周边血管呈环状、树枝状渐进性回声增强,而后门脉相随周边肝实质的强化而回声逐渐减弱,对比正常肝实质呈低回声,表现出典型的快进快出的强化特点.超声造影对于d≤3cm的小肝癌病灶检出率为90.6%,特异性96.2%,阳性预测值96.7%,阴性预测值86.7%,其中对于d<1cm的微小肝癌检出率为85.7%.结论:实时超声造影技术可提供肿瘤的动态血流信息,有助于微小病灶的诊断与鉴别诊断.     

心肌声学造影在冠心病诊断中的研究进展

心肌造影超声心动图 (Myocardial ContrastEchocardiography,MCE)在评价心肌血流灌注中的运用成为一项十分热门的研究课题。MCE是指将含有微气泡的造影剂直接经冠状动脉或外周静脉注入 ,当微泡通过心肌微血管床时 ,应用二维或多普勒超声技术增强含血心肌的超声心动图显像 ,观察心肌血流灌注、冠脉血流储备。本文就近年来心肌声学造影在冠心病诊断方面的研究作一综述。1　声学造影剂的研究声学造影剂是 MCE的决定性因素之一。早年造影剂所产生的微泡直径大、不均匀、易破裂 ,无法通过肺循环进入左心室。故这项技术主要用于右心显影 ,认…     

Diagnosis of NASH using delayed parenchymal imaging of contrast ultrasound.

BACKGROUND AND AIMS: Non alcoholic steatohepatitis (NASH) is one of the representative liver diseases in the developed countries. Diagnosis of NASH is dependent on histological findings from liver biopsy. Usefulness of contrast ultrasound with Levovist for diagnosis of NASH is described. METHODS AND MATERIALS: Clinical study: Ultrasound contrast agent, Levovist of 2.5g was injected intravenously. The liver was scanned at 5, 10, 15, 20, 30, 40, and 50min after Levovist injection in different planes using a contrast specific ultrasound mode. Changes in microbubble accumulation in the liver were evaluated. The signal intensity from regions of interest (ROI) on the contrast images was measured and accumulation and decrescence of microbubbles were estimated using the time intensity curves (TICs). The image data and TICs were evaluated by blind reviewers. Fifteen patients with NASH, 8 with alcoholic steatohepatitis (ASH), 45 with non alcoholic fatty liver (NAFL), 10 with chronic hepatitis C (CHC) and 10 healthy volunteers were studied. Animal study: Methionine-choline-deficient diet (MCDD) fed rats were used for NASH model. Correlation between microbubble accumulation and morphological and functional changes of sinusoidal endothelium and macrophage was evaluated. RESULTS: The maximum intensity of contrast ultrasound was decreased and time course decrescence was more rapid in NASH than the other groups. These changes were correlated to the degree of centrilobular and pericellular fibrosis but not to steatosis in histological study. Disturbance of microbubble accumulation was correlated with sinusoidal function rather than morphological changes such as fibrosis and parenchymatitis in the animal studies. CONCLUSIONS: The Levovist contrast study enables differential diagnosis between NASH and other diseases that provoke steatosis and fibrosis.     

Microbubble-induced increase in ablation of liver tumors by high-intensity focused ultrasound

We studied the possibility of using high-intensity focused ultrasound (HIFU) together with a microbubble agent to treat hepatocellular carcinoma. Development of liver tumors in rats was induced by administration of Dimethylnitrosamin (100ppm). Rats with liver tumors were anesthetized, underwent laparotomy, and were given the microbubble agent Levovist or saline intravenously. After the injection, the liver was exposed to HIFU for 30s (2.18MHz, 600W/cm(2), 40mm in diameter). Immediately after HIFU exposure, ultrasound images of the HIFU area were evaluated. Then the liver was excised and the volume of coagulated tissue was measured. The mean volumes of hyperechoic areas after HIFU were as follows (mm(3), Levovist versus saline: 355.3+/-180.7 versus 47.4+/-35.6, P<0.001, n=13). The volumes of liver tissue coagulated by HIFU were as follows (mm(3), Levovist versus saline: 275.3+/-120.0 versus 60.1+/-23.6, P<0.001, n=13). On microscopic examination of areas exposed to HIFU, implosion cysts were seen, and many cancer cells were found to have been destroyed completely (loss of cell membranes or nuclei). In conclusion, the microbubble agent Levovist can increase the volume of tissue coagulated by HIFU.     

Decreased accumulation of ultrasound contrast in the liver of nonalcoholic steatohepatitis rat model

AIM:To investigate the diagnosis of nonalcoholic steatohepatitis(NASH) using contrast ultrasonography in the NASH rat model.METHODS:The liver in methionine choline-deficient diet(MCDD) rats,a NASH model constructed by feeding an MCDD,was examined by contrast ultrasonography at weeks 2,4,8,12 and 16,with late phase images of contrast ultrasonography(Kupffer imaging) in which contrast enhancement was achieved by incorporation of a contrast agent by Kupffer cells(KCs),and images were compared to those in rats ...     

An implantable rat liver tumor model for experimental transarterial chemoembolization therapy and its imaging features

AIM: To establish an ideal implantable rat liver tumor model for interventional therapy study and examine its angiographic signs and MRI, CT features before and after embolization. METHODS: Forty male Wistar rats were implanted with Walker-256 tumor in the left lateral lobe of liver. Digital subtraction angiography (DSA) and transarterial chemoembolization were performed on day 14 after implantation. Native computer tomography (CT, n=8) and native magnetic resonance (MR, n=40) were performed between the day 8 and day 21 after implantation. The radiological morphological characteristics were correlated with histological findings. RESULTS: Successful implantation was achieved in all forty rats, which was confirmed by CT and MRI. MR allowed tumor visualization from day 8 while CT from day 11 after implantation. The tumors were hypodensity on CT, hypointense on MR T1-weighted and hyperintense on T2-weighted. The model closely resembled human hepatocarcinoma in growth pattern and the lesions were rich in vasculature on angiography and got its filling mainly from the hepatic artery. Before therapy, tumor size was 211.9+/-48.7 mm(3). No ascites, satellite liver nodules or lung metastasis were found. One week after therapy, tumor size was 963.6+/-214.8 mm(3) in the control group and 356.5+/-78.4mm(3) in TACE group. Ascites (4/40), satellite liver nodules (7/40) or lung metastasis (3/40) could be seen on day 21. CONCLUSION: Walker-256 tumor rat model is suitable for the interventional experiment. CT and MRI are helpful in animal optioning and evaluating experimental results.     

Characterization of focal hepatic lesions with contrast-enhanced C-cube gray scale ultrasonography

AIM: To characterize enhancement patterns of focal hepatic lesions using C-cube gray scale sonography with a microbubble contrast agent and to evaluate its usefulness in differential diagnosis of hepatic lesions. METHODS: Fifty-four patients with 58 focal hepatic lesions were examined with Levovist-enhanced C-cube gray scale sonography. The final diagnosis of hepatic lesions was 29 primary liver cancers, 4 metastases, 8 hemangiomas, 12 focal nodular hyperplasias, 2 inflammatory pseudotumors of the liver and 3 angiomyolipomas. The initiation time of enhancement in various lesions and enhancement duration after administration of contrast agent were compared. Vascular findings in lesions were classified as peripheral enhancement, homogenous enhancement, mosaic enhancement and no enhancement depending on microbubble signals in the lesion relative to the liver parenchyma. RESULTS: The initiation time of enhancement in hemangioma (48+/-12 s) was significantly later compared to other lesions (P<0.05). The enhancement duration of malignancies (69+/-33 s in primary liver cancer, 61+/-23 s in metastasis) was significantly shorter compared to benign lesions (P<0.05). Intranodular enhancement appearing at arterial phase and decreasing at portal venous phase was considered characteristic for malignancy. Intranodular enhancement did not appear earlier than the liver parenchyma, and peripheral enhancement pattern was regarded as positive findings for hemangioma. Intranodular enhancement appeared in the arterial phase, and homogenous enhancement pattern sustained in the whole portal venous phase were regarded as positive findings for focal nodular hyperplasia. No microbubble signals appeared in two inflammatory pseudotumors of the liver. CONCLUSION: C-cube gray scale sonography can demonstrate dynamic intranodular enhancement in various focal hepatic lesions. The information provided by this methodology may be useful in the differential diagnosis of hepatic lesions.     

声学造影剂及二次谐波成象在肝癌诊断中的作用及局限性

目的：探讨微气泡型声学造影剂和二次谐波成象在肝癌诊断中的作用及局限性。方法：１３例肝癌病人经外周静 脉注射造影剂（剂量０．５～ １０ｍｌ）后检查。二次谐波成象用 １．７／３４ＭＨｚ（ＡＴＬ－ＨＤＩ ５０００）或１．８／３．６ＭＨｚ（ＨＰ ５５００）。结 果：肝动脉期肝脏多数无明显增强,少数病灶内出现斑点状回声增强,门静脉增强后肝组织才明显增强,但肿瘤组织 增强不明显。增强后有利于低回声病灶的显示而对高回声病灶或中高混杂回声病灶显示无益。增强后可显示更多 的瘤血管。结论：微气泡型声学造影剂及二次谐波成象反映的主要是肝组织总体供血量的变化,相对于正常肝组织 来说肝癌总是少血管的,谐波成象可以显示更多的血管。     

Doppler and harmonic ultrasound for hepatocellular carcinoma

Ultrasound (US) is the imaging method most frequently used for the detection and diagnosis of hepatocellular carcinoma (HCC). US image quality has greatly improved in recent years, with advances in transducer, beam-former technology and sophisticated image processing. In addition, the recent availability of US contrast agents including first- and second-generation contrast agents and the remarkable advances in US technology have led to the rapid development of new imaging methods such as low and high mechanical index (MI) imaging technology for the vascular phase and parenchymal phase of the liver. In terms of contrast agent, most reported studies in Asian countries have used a very fragile, first-generation microbubble agent. Nowadays, more stable,second-generation contrast agents are developing and used in clinical application to the liver. In the future, better results can be obtained in the diagnosis of HCC, decision of treatment method and assessment of therapeutic response if more durable contrast agents are used with advanced US techniques. In this article, the principles, methods, imaging findings and potential roles of new diagnostic US techniques with contrast agents in the diagnosis of HCC are discussed.