Effect of externally applied focused acoustic energy on clot disruption in vitro.

Application of low-frequency ultrasound for clot disruption has been suggested as a potential therapy to enhance thrombus dissolution, but the optimal mode for delivery of ultrasound with clot-disruptive properties has not yet been extensively explored. Target-specific effects are desirable and may be accomplished by focusing the ultrasound. Adequate focusing, however, requires a short wavelength. The aim of this study was to compare the clot-disruptive effects of different modalities of focused acoustic energy. An in vitro model (10 blood clots for each modality) was used to test the clot-disruptive capacity of (i) shock waves generated in an electrohydraulic lithotriptor; (ii) focused continuous ultrasound of frequency 1.1 MHz, delivered from a specially constructed piezoelectric transducer; and (iii) focused pulse-modulated ultrasound of frequency 1.1 MHz delivered from the same transducer. Exposure to 30 s of focused pulse-modulated ultrasound caused a marked reduction (99+/-2%) in clot weight compared with 30 shock waves (11+/-5%) or 30 s exposure to focused continuous wave ultrasound (11+/-6%) (P<0.0001). The observed marked and rapid disruptive effect on blood clots of focused high-frequency ultrasound indicates an alternative approach for external ultrasound-mediated thrombus destruction in vivo. The focused pulse-modulated technique has potential to exhibit the desired effect in a well-defined target volume and provides the means for control of the average power.     

彩色多普勒超声诊断原发性肝癌并门静脉癌栓的价值

目的探讨彩色多普勒超声诊断原发性肝癌(HCC)并门静脉癌栓(PVTT)的价值。方法回顾性分析彩色多普勒超声诊断HCC并PVTT 50例患者的超声检查资料,并与50例正常组(无肝胆疾病)的超声检查结果对照。结果声像图表现为门静脉内径明显增宽,血流束变细或充盈缺损,甚至中断;癌栓内探及动脉血流频谱12例(24.0%),门静脉海绵样变性18例(36.0%)。结论彩色多普勒超声不仅可以较准确地诊断HCC,而且还能反映门静脉及肝动脉的形态及血流动力学变化,对HCC并PVTT的诊断具有重要的临床价值。     

Characterization of portal vein thrombus with the use of contrast-enhanced sonography.

OBJECTIVES: To select an appropriate treatment regimen, it is essential to accurately characterize the nature of a thrombus. This study prospectively assessed the ability of contrast-enhanced sonography to differentiate between benign and malignant portal vein thrombosis in a population of high-risk patients. METHODS: Fifty-five patients (43 men and 12 women; mean age, 66 years; range, 55-83 years) with thrombi of the portal venous system were examined by power Doppler sonography and contrast-enhanced sonography with the intravenous contrast agent SH U 508A (Levovist; Schering AG, Berlin, Germany). Of the thrombi, 40 were characterized as malignant and 15 as benign. Pulsatile flow in the thrombus on power Doppler sonography and positive enhancement of the thrombus on contrast-enhanced sonography were judged as indications of a malignant thrombus. The sensitivity and specificity of both methods in differentiating the nature of the thrombus were evaluated. RESULTS: The detection of pulsatile flow in a portal vein thrombus as the criterion for diagnosing malignant portal vein thrombus yielded overall sensitivity of 82.5% and specificity of 100%, whereas positive enhancement of the portal vein thrombus itself as a criterion for diagnosing malignancy yielded overall sensitivity and specificity of 100% for each. CONCLUSIONS: Contrast-enhanced sonography can be helpful in discriminating between benign and malignant portal vein thrombi.     

Correlation of the echogenicity and structure of clotted blood

The echogenicity of clotting human blood in sterile plastic bags was studied for up to 21 days and correlated with the histology of the clots. As observed with a 6-MHz A-scanner and a 5-MHz real-time gray-scale scanner, fresh blood and fresh clots were rich in internal echoes. The blood clot gradually became anechoic as a result of erythrocyte packing, hemolysis, and formation of fibrin thrombus, except for the irregular upper border, which also remained histologically inhomogeneous. This study shows that the echogenicity of a hematoma or clot is dependent on its histology; namely, on the distribution and integrity of cells within the clot.     

门脉栓子的双功多普勒检查

应用双功多普勒检测了４５例原发性肝癌患者门脉血流动力学。检出门脉栓子１３例，并对门脉栓子前方、后方及栓子处残余管腔内、栓子内部的血流状态、血流速度、血流量进行了检测。结果表明，本技术不仅可显示门脉栓子的部位、大小和形态，尚能判断栓塞是否完全及了解其它血流动力学信息，指导临床治疗方式的选择和预后判断，并有助于对门脉栓子良恶性的鉴别。     

Initiation and propagation of coagulation from tissue factor-bearing cell monolayers to plasma: initiator cells do not regulate spatial growth rate.

Exposure of tissue factor (TF)-bearing cells to blood is the initial event in coagulation and intravascular thrombus formation. However, the mechanisms which determine thrombus growth remain poorly understood. To explore whether the procoagulant activity of vessel wall-bound cells regulates thrombus expansion, we studied in vitro spatial clot growth initiated by cultured human cells of different types in contact pathway-inhibited, non-flowing human plasma. Human aortic endothelial cells, smooth muscle cells, macrophages and lung fibroblasts differed in their ability to support thrombin generation in microplate assay with peaks of generated thrombin of 60 +/- 53 nmol L(-1), 135 +/- 57 nmol L(-1), 218 +/- 55 nmol L(-1) and 407 +/- 59 nmol L(-1) (mean +/- SD), respectively. Real-time videomicroscopy revealed the initiation and spatial growth phases of clot formation. Different procoagulant activity of cell monolayers was manifested as up to 4-fold difference in the lag times of clot formation. In contrast, the clot growth rate, which characterized propagation of clotting from the cell surface to plasma, was largely independent of cell type (< or = 30% difference). Experiments with factor VII (FVII)-, FVIII-, FX- or FXI-deficient plasmas and annexin V revealed that (i) cell surface-associated extrinsic Xase was critical for initiation of clotting; (ii) intrinsic Xase regulated only the growth phase; and (iii) the contribution of plasma phospholipid surfaces in the growth phase was predominant. We conclude that the role of TF-bearing initiator cells is limited to the initial stage of clot formation. The functioning of intrinsic Xase in plasma provides the primary mechanism of sustained and far-ranging propagation of coagulation leading to the physical expansion of a fibrin clot.     

三维血管能量成像对门静脉癌栓和血栓的鉴别诊断

目的探讨门静脉系统癌栓与血栓的三维血管能量成像（3D-PDA）的表现及其鉴别诊断。方法对47例经临床及病理证实的门静脉栓塞的患者（癌栓37例，血栓10例）进行三维血管能量成像检查，分析门脉癌栓与血栓的不同特点。结果三维血管能量成像显示癌栓内血流丰富，显示条状多分支或网状结构。三维血管能量成像显示门静脉血栓内无血流信号，靠近管壁的血流光滑平直，腔内见曲线状血流，局部充盈缺损。结论三维血管能量成像可以立体的显示血管走行及分布情况，有助于癌栓和血栓的鉴别诊断。     

肝细胞肝癌门静脉癌栓介入分型及其临床应用价值

目的:探讨适合指导介入治疗的肝细胞肝癌门静脉癌栓介入分型。方法:根据肝细胞肝癌合并门静脉癌栓患者的动态增强CT或MR影像学表现,将门静脉癌栓分为Ⅰ~Ⅴ共5型,包括Ⅰ型、Ⅱa型/Ⅱb型、Ⅲa型/Ⅲb型/Ⅲc型、Ⅳa型/Ⅳb型、Ⅴ型,其中将Ⅰ~Ⅳ型同时合并肝动脉门静脉瘘归为Ⅴ型。观察不同分型患者经肝动脉化疗栓塞(transcatheter arterial chemoembolization,TACE)联合门静脉支架+放射性碘-125粒子条植入治疗的效果。结果:117例入选患者介入分型为Ⅰ型占10.2%(12/117)、Ⅱ型占17.1%(20/117)、Ⅲ型占53%(62/117)、Ⅳ型占19.6%(23/117)、Ⅴ型占16.2%(19/117)。所有患者均接受介入治疗,术后即刻造影显示,68例(93.1%)患者门静脉灌注明显改善。术后1~3个月增强MR/CT随访显示,植入碘-125粒子部位的癌栓均较术前明显萎缩,有效控制。结论:肝细胞肝癌合并门静脉癌栓的介入分型有助于指导临床制定个体化的介入治疗策略,使患者获益,值得临床推广。     

高强度聚焦超声治疗门静脉癌栓

目的探讨高强度聚焦超声(HIFU)治疗门静脉癌栓的有效性及临床应用价值.方法对26例晚期肝癌合并门静脉癌栓患者的33支门静脉主干或(和)第1级分支内癌栓进行HIFU治疗,观察治疗后癌栓支门静脉血流变化、癌栓回声和消减变化以及患者肝功能、腹水和生活质量改善情况.结果治疗前6例8支门静脉充满型癌栓支彩色多普勒超声无血流信号,癌栓呈低回声或等回声;治疗2～3次后,7支门静脉癌栓由低回声或等回声变为中等回声或强回声,癌栓体积较治疗前缩小1/2～1/3,门静脉内见到彩色血流信号;第5次治疗后,8支门静脉癌栓支均见彩色血流信号,癌栓体积进一步缩小,其中6支见到连续稳定的再通血流信号,患者肝功能、腹水和生活质量均有不同程度的改善.20例25支非充满型门静脉癌栓经3～5次治疗后,癌栓回声明显增强,其体积缩小1/2～1/5,原来连续不稳定的血流信号变为连续稳定的再通血流信号.结论HIFU治疗门静脉癌栓安全、痛苦小、无创伤、有肯定的疗效,有望成为一种用于治疗大多数门静脉癌栓的新方法.     

门静脉栓塞病变的超声表现及病因分析

目的 观察门静脉栓塞病变（PVE）超声表现,分析其病因。方法 回顾性分析257例经病理、其他影像学检查或临床证实的PVE患者的临床和超声资料,观察栓子超声表现,分析病因、性质及发生部位。结果 PVE超声表现为门静脉系统内异常回声,部分或完全充填管腔;8例栓子内可见搏动性动脉血流信号（8/257,3.11%）,25例（25/257,9.73%）门静脉（PV）呈海绵样变。PVE常见病因依次为为原发性肝癌（173/257,67.31%）、肝硬化（36/257,14.01%）及肝转移癌（30/257,11.67%）。194例（194/257,75.49%）PV癌栓中,原发性肝癌占80.41%（156/194）;血栓63例（63/257,24.51%）,其中肝硬化占57.14%（36/63）。PVE累及部位依次为门静脉主干及分支（254/257,98.83%）、肠系膜上静脉（36/257,14.01%）、脾静脉（30/257,11.67%）、下腔静脉（19/257,7.39%）、肠系膜下静脉（1/257,0.39%）。超声诊断门静脉癌栓的敏感度为4.12%（8/194）。结论 PVE超声表现具有一定特征,但超声鉴别诊断栓子性质敏感度较低;原发性肝癌为PVE的最常见病因。     

High incidence of thrombus formation without impedance rise during radiofrequency ablation using electrode temperature control

The authors hypothesized that during RF ablation, the electrode to tissue interface temperature may significantly exceed electrode temperature in the presence of cooling blood flow and produce thrombus. In 12 anesthetized dogs, the skin over the thigh muscle was incised and raised to form a cradle that was superfused with heparinized canine blood (ACT > 350 s) at 37 degrees C. A 7 Fr, 4-mm or 8-mm ablation electrode containing a thermocouple was held perpendicular to the thigh muscle at 10-g contact weight. Interface temperature was measured at opposite sides of the electrode using tiny optical probes. RF applications (n = 157) were delivered at an electrode temperature of 45 degrees C, 55 degrees C, 65 degrees C, and 75 degrees C for 60 seconds, with or without pulsatile blood flow (150 mL/min). Without blood flow, the interface temperature was similar to the electrode temperature. With blood flow, the interface temperature (side opposite blood flow) was up to 36 degrees C and 57 degrees C higher than the electrode temperature using the 4- and 8-mm electrodes, respectively. After each RF, the cradle was emptied and the electrode and interface were examined. Thrombus developed without impedance rise at an interface temperature as low as 73 degrees C without blood flow and 80 degrees C with blood flow (11/16 RFs at 65 degrees C electrode temperature using 4 mm and 13/13 RFs at an electrode temperature of 55 degrees C using an 8-mm electrode with blood flow). With blood flow, interface temperature markedly exceeded the electrode temperature and the difference was greater with an 8-mm electrode (due to greater electrode cooling). In the presence of blood flow, thrombus occurred without an impedance rise at an electrode temperature as low as 65 degrees C with a 4-mm electrode and 55 degrees C with an 8-mm electrode.     

肝癌门静脉癌栓及其血流动力学的彩色多普勒研究

原发性肝癌（ＨＣＣ）具有侵蚀周邻血管的特性，常常侵及门静脉及肝静脉系统，尤以前者多见，可引起动静脉分流，造成门静脉血流方向的紊乱或逆流。本文对１０例ＨＣＣ伴门静脉癌桂的患者进行了彩色多普勒血流显像（ＣＤＦＩ）检查，并均行血管造影。结果表明，ＣＤＦＩ可清晰地显示出静脉癌栓及其血供状态和门静脉血流方向的变化。其特征表现为：①门静脉管腔内见动脉样频谱；②门静脉原向肝的血流变为离肝的血流。上述结果与血管造影符合率为９０％。因此，ＣＤＦＩ对ＨＣＣ的分级和治疗方法的选择具有重要的意义。     

术前及术中超声造影对下腔静脉癌栓是否合并血栓的诊断价值

目的探讨术前及术中超声造影对下腔静脉癌栓是否合并血栓的诊断价值。 方法选取2017年10月至2019年3月解放军总医院收治的发现肾肿瘤伴下腔静脉癌栓并行腹腔镜手术治疗的患者60例，所有患者均于术前及术中行超声造影检查，以典型增强模式判断癌栓是否合并血栓，并最终取得术后病理结果。以术后病理结果为"金标准"，计算术前及术中超声造影评估癌栓合并血栓的敏感度、特异度、准确性、阳性预测值和阴性预测值。 结果60例下腔静脉癌栓患者均接受了机器人辅助腹腔镜下根治性肾切除联合下腔静脉内癌栓切除术。根据病理结果，下腔静脉癌栓合并血栓者10例（16.7%），其中术前超声造影漏诊2例，另有2例癌栓头部坏死组织被术前及术中超声造影误诊为血栓。术前与术中超声造影评估癌栓合并血栓的敏感度、特异度、准确性、阳性预测值、阴性预测值分别为80.0%、96.0%、93.3%、80.0%、96.0%和100.0%、96.0%、96.7%、83.3%、100.0%。 结论术前及术中超声造影对下腔静脉癌栓是否合并血栓有较好的鉴别诊断效能，可为手术方式的选择提供重要信息和依据，具有较高的临床应用价值。     

多层螺旋CT双期扫描及三维成像对肝癌门静脉癌栓的诊断价值

目的:探讨多层螺旋CT对肝癌门静脉癌栓的影像特征及其诊断价值。材料与方法:对诊断为肝癌的35例患者行MSCT平扫及动态增强扫描并进行2D及3D重建图象以显示门脉情况。结果:无癌栓10例占30%,根据癌栓不同部位分为门脉主干、左、右支及肿瘤周围小分支。门静脉主干占7例,约25%,门静脉分支癌栓占17例,其中3例可见病灶区小分支癌栓,40%,门静脉、肝静脉,下腔静脉1例,占5%。结论:MSCT成像,可较好的多方位显示癌栓部位及其类型,对门静脉癌栓检出作出准确判断,为临床诊断治疗提供了参考依据。     

原发性肝癌合并门静脉癌栓血液动力学改变的双期增强螺旋CT表现

目的 探讨原发性肝癌合并门静脉癌栓血液动力学改变的双期增强螺旋CT表现。方法 用高压注射器经肘正中静脉注入造影剂后分别于20s和60s行全肝螺旋CT动脉期和门脉期扫描。每例CT片均经三名有经验的医师分别阅读后，再共同讨论分析，并达成一致共识。结果 27例中，门静脉主干发生癌栓者3例，右支癌栓8例．左支癌栓9例，主干和右支同时受累者3例，主干和左支受累者2例，主干和左右支均有癌栓者2例。正常肝组织的异常灌注者表现为动脉期不规则片状或楔形较均匀高密度影，而门脉期恢复为等密度，按叶、段、亚段分布者分别为5、16、6例。结论 正常肝组织异常灌注的主要原因是肝动脉血的门静脉分流。     

Changes in cerebral blood flow before,during, and after forward and backward walking in stroke patients trained using virtual reality walking videos with deliberately induced inaccuracies in walking speed estimations

[Purpose] The aim of this study was to examine the effects of virtual reality (VR) training, with deliberately induced inaccuracies in walking speed estimations, on brain activity. [Participants and Methods] The study participants were 21 stroke patients, and the walking tasks involved forward and backward walking. While the VR walking speed was set at 3 km/h, estimation errors were induced by using an actual walking speed of 1 km/h during the walking tasks. Cerebral blood flow was measured using two functional near-infrared spectroscopy (fNIRS) channels located over the left and right prefrontal cortices, to determine changes in oxyhemoglobin levels from the resting state. Cerebral hemodynamics were compared during and after the VR training. [Results] The backward walking task induced a significant increase in cerebral blood flow in the right prefrontal cortex during and after the VR training. No significant changes were observed during the forward walking task. [Conclusion] In the backward walking condition, greater activation of the right prefrontal cortex was observed during and immediately after the VR training. Watching VR may have led to inaccurate walking-speed estimations, necessitating postural control (which may be attributed to the activation of the prefrontal cortex) during walking.     

Inhibition of tissue factor limits the growth of venous thrombus in the rabbit

Summary.  Antibody mediated inhibition of tissue factor (TF) function reduces thrombus size in ex vivo perfusion of human blood over a TF-free surface at venous shear rates suggesting that TF might be involved in the mechanism of deep vein thrombosis. Moreover, TF-bearing monocytes and polymorphonuclear (PMN) leukocytes were identified in human ex vivo formed thrombi and in circulating blood. To understand the role of TF in thrombus growth, we applied a rabbit venous thrombosis model in which a collagen-coated thread was installed within the jugular vein or within a silicon vein shunt. The effect of an inhibitory monoclonal antirabbit TF antibody (AP-1) or Napsagatran, a specific inhibitor of thrombin, was quantified by continuously monitoring ¹²⁵I-fibrinogen incorporation into the growing thrombi. The antithrombotic effect obtained with the anti-TF antibody was comparable to the effect observed with the thrombin inhibitor napsagatran suggesting that in this animal model the thrombus propagation is highly TF dependent. Immunostaining revealed that TF was mostly associated with leukocytes within the thrombi formed in the jugular vein or in the silicon vein shunt. Ex vivo perfusion experiments over collagen-coated coverslips demonstrated the presence of TF-bearing PMN leukocytes in circulating blood. The results suggest that in rabbits venous thrombus growth is mediated by clot-bound TF and that blocking the TF activity can inhibit thrombus propagation.     

原发性肝癌门脉癌栓的双期增强CT表现

目的：探讨原发性肝癌门静脉癌栓螺旋CT双期增强扫描表现。材料与方法：对36例门静脉癌栓患者行螺旋CT双期增强扫描,观察门静脉癌栓在CT上的表现。结果：36例TIPV患者在螺旋CT动态增强扫描时均显示出门静脉内癌栓及相关的阳性征象,表现为门静脉扩张、门静脉腔内充盈缺损及“门静脉铸型”,门静脉周围可见网状供血动脉。36例中,门静脉主干合并右支癌栓12例,门静脉主干合并左支癌栓8例,主干和左右支均有癌栓者9例,单纯右支癌栓4例,单纯左支癌栓3例。结论：螺旋CT双期增强扫描是诊断门静脉癌栓的有效方法,可以完整地提供门静脉癌栓的全部资料。     

高强度聚焦超声联合肝动脉化疗栓塞治疗门静脉癌栓的临床研究

目的 探讨高强度聚焦超声（HIFU）联合肝动脉化疗栓塞（TACE）治疗门静脉癌栓（PVTT）的安全性和有效性。方法将42例原发性肝癌（HCC）合并门静脉癌栓（PVTT）患者分为两组,A组（22例）采用HIFU联合TACE进行治疗,B组（20例）单纯采用TACE治疗。结果HIFU联合TACE组治疗后PVTT有5例消失,12例缩小,比TACE组疗效明显（P〈0．05）。HIFU联合TACE组,有11例患者恢复门静脉血流,癌栓内血供较单纯TACE治疗组明显减少（P〈0．05）。联合治疗组中位生存期13．8个月,较同期TACE组中位生存期7．9个月明显延长（P〈0．05）。结论HIFU联合TACE治疗PVTT是一种新的安全、有效、微创的治疗方法,能明显提高患者生活质量,延长寿命。