兔活体主动脉脂质斑块的腔内超声显像和病理的对照研究

１１条新西兰兔进行血管腔内超声研究。其中８条经高胆固醇饲养６个月；另３条予正常饮食对照。采用６．２Ｆ，频率２０ＭＨｚ腔内超声导管。由腹主动脉下端水平插入超声导管至升主动脉，然后逐步奶出，观察主动脉内膜，中膜和外膜的形态特征。     

动脉粥样硬化兔斑块易损性的血管内超声评价

目的应用血管内超声（IVUS）技术评价易损斑块的影像学特征。方法30只实验兔给予球囊损伤腹主动脉＋高脂饲料喂养，12周末将实验兔随机分为A、B两组，在A组腹主动脉斑块处转染携带人野生型P53基因的重组腺病毒载体，2周后给予所有兔中国斑点蝰蛇毒（CRVV）和组胺触发，14周末进行体表超声、血管内超声和病理学检查。结果A组斑块破裂率较B组显著增高（P〈0．05）。IVUS示斑块破裂组的血管外弹力膜面积（EEMA）、斑块面积（PA）、管腔面积狭窄百分率（LAS%）及偏心指数（EI）显著大于未破裂组（P〈0．01～0．05）；斑块破裂组的内一中膜厚度（IMT）、收缩期峰值流速（Vp）显著大于未破裂组，而平均回声强度的校正值（AIIc％）显著低于未破裂组（P均〈0．05）。结论应用野生型P53基因转染可导致斑块的不稳定性，IVUS能够准确识别易损斑块，为临床早期发现易损斑块并预测斑块破裂提供了可靠的方法。     

动脉血管腔内超声显像的三维重建

超声诊断动脉血管病变日益广泛。血管腔内显象技术的应用，可从二维血管腔成像成为三维（立体）显示。为了能更好显示动脉血管的三维形态，我们建立了血管腔内超声显象的计算机三维重建系统。通过计算机三维重建表面提取法，依次标出每个切面中冠状动脉的内膜面和外膜面，最后得到其数字化了的三维图像。结果显示，经计算机三维重建的５０个正常人离体右冠状动脉血管腔内超声切面，其形态和实际十分接近。     

人体大血管的腔内超声显像

血管腔内超声显象(IVUl)是将超声探头置于血管腔内诊断血管病变的新方法。本研究应用该技术于人体主动脉和腔静脉,开辟了超声诊断血管病变的新途径和新视野。对今后开展人体IVUI检查,建立了有益的经验。     

血管内超声检测易损斑块的研究进展

早期检测易损斑块对于急性冠脉综合征的防治有重要意义。血管内超声是检测易损斑块的重要方法,有着独特优势。本文就血管内超声及其衍生技术检测易损斑块的基本原理和研究进展作一综述。     

血管腔内超声显像三维重建的实验研究

血管腔内超声显像三维重建术能够直观地显示血管和动脉粥样硬化斑块的空间结构，提供二维图像所不能得到的信息。本文用表面提取法成功地对７根正常根人离体血管标本进行腔内超声显像和三维重建。     

血管内超声和病理学分析对比研究动脉粥样硬化兔不稳定斑块的破裂和血栓形成

目的　探讨血管内超声 (IVUS)对斑块破裂、血栓形成的诊断价值。方法　通过球囊损伤 高脂 ( 1%胆固醇 )喂养雄性新西兰纯种兔建立动脉粥样硬化动物模型 ,斑块部位转染携带 p5 3基因的重组腺病毒载体 ,促使斑块向不稳定方向转化 ,然后给予鲁塞尔蝰蛇毒 (RVV)和组胺药物触发 ,造成实验性斑块破裂、血栓形成。在药物触发前后对家兔进行IVUS检查 ,结果与组织病理学检查相比较。结果　IVUS发现 14只家兔中有 12只共 18处发生斑块破裂、血栓形成 ,病理学检查发现 14只兔中有 12只共 2 0处斑块破裂、血栓形成。IVUS诊断斑块破裂、血栓的真阳性率为 85 % ,假阴性率为 15 % ,敏感性为 85 % ,特异性 67%。两者在对血栓长度的测量上高度相关 (r =0 .73 ,P <0 .0 1) ,但对横截面积的测量上无相关性(r =0 .19,P >0 .0 5 )。结论　IVUS能够较为准确地识别斑块破裂及血栓形成     

冠脉腔内超声评价粥样硬化斑块破裂脂质溢出1例

冠脉腔内超声评价粥样硬化斑块破裂脂质溢出１例上海医科大学中山医院（２０００３２）上海市心血管病研究所钱菊英，沈学东，魏盟，林佑善，严卫，李清，何梅先，陈灏珠动脉粥样硬化斑块破裂脂质溢出是造成急性心肌梗塞及不稳定型心绞痛的重要因素之一。正确诊断有助于及...     

心肌梗死相关冠状动脉的腔内超声研究

目的　比较心肌梗死相关冠状动脉造影和血管内超声下粥样斑块的特征。方法　 2 5例急性心肌梗死患者的梗死相关动脉 (IRA)在成功经皮冠状动脉腔内成形术 (PTCA)后即刻行冠状动脉内超声检查 ,结果与冠状动脉造影进行定量和定性比较。结果　①在PTCA部位 ,平均面积狭窄 5 0 %～ 70 % ,斑块横截面积是血管横截面积的 (5 0± 18) % ;②冠状动脉内超声下病变的近端和远端粥样硬化发生率为 70 % ,而冠状动脉造影下上述部位的病变率仅 30 % (P =0 .0 0 1) ;③ 6 9%的斑块属于软斑块 ,硬斑块占 31% ,但是其斑块面积却大于前者 [(5 0± 16 ) %vs (39± 19) % ,P =0 .0 1] ;④PTCA部位所有近端与远端参考段血管腔内斑块面积与血管横截面积之间相关性良好 (r =0 .49,P =0 .0 0 0 1) ,病变段血管腔内斑块面积与血管截面积之间相关性良好 (r =0 .49,P =0 .0 0 3)。结论　冠状动脉内超声下梗死部位斑块负荷极重 ,同时病变的近远端存在广泛性粥样硬化和代偿性扩张     

正常兔腹主动脉、肾动脉声学造影的实验研究

目的 探讨动脉声学造影的价值和可行性。为声学造影剂在大、中血管中的临床应用提供理论依据。方法 正常大白兔5只，耳缘静脉注射自制脂膜氟烷超声造影剂“脂氟显”观测腹主动脉、肾动脉二维形态及彩色多普勒血流显像，对照分析造影前、后检查结果。结果 “脂氟显”造影剂在腹主动脉、肾动脉中平均显影时间为60min；造影前腹主动脉内膜显示不清，造影后回声增强，内膜线明亮清晰；造影后肾动脉彩色血流信号明显增多，多普勒视频密度与造影前相比有显著差异。结论 造影剂可显著改善大、中动脉二维、彩色血流显像，动脉声学造影切实可行。     

高强度聚焦超声致兔胃壁损伤的实验研究

目的 探讨模拟临床照射剂量条件下高强度聚焦超声(HIFU)对兔胃壁的破坏程度，以了解HIFU技术的安全性。方法 HIFU体外照射20只新西兰大白兔胃壁，观察照射过程中超声影像改变、局部损伤区的组织病理变化以及术后生存情况。结果 监控超声图像可较敏感的反映出HIFU照射组织损伤区的变化，术后病理观察可以证实兔胃壁发生急性坏死。结论 临床治疗剂量的HIFU照射足以使胃壁发生急性坏死，致胃穿孔发生导致死亡。     

Contrast-Enhanced Intravascular Ultrasound Pulse Sequences for Bandwidth-Limited Transducers

We demonstrate two methods for vasa vasorum imaging using contrast-enhanced intravascular ultrasound, which can be performed using commercial catheters. Plaque neovascularization was recognized as an independent marker of coronary artery plaque vulnerability. IVUS-based methods to image the microvessels available to date require high bandwidth (−6 dB relative frequency bandwidth >70%), which are not routinely available commercially. We explored the potential of ultraharmonic imaging and chirp reversal imaging for vasa vasorum imaging. In vitro recordings were performed on a tissue-mimicking phantom using a commercial ultrasound contrast agent and a transducer with a center frequency of 34 MHz and a −6 dB relative bandwidth of 56%. Acoustic peak pressures <500 kPa were used. A tissue-mimicking phantom with channels down to 200 μm in diameter was successfully imaged by the two contrast detection sequences while the smallest channel stayed invisible in conventional intravascular ultrasound images. Ultraharmonic imaging provided the best contrast agent detection.     

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.     

血管应变显像软件的研制及应用的初步研究

目的 探讨评价血管及斑块应变的新方法。 方法 根据理论分析，自行设计了血管应变显像的软件程序。在兔动脉粥样硬化的模型中，进行了腹主动脉血管内超声检查，应用软件程序分析腹主动脉的应变分布。 结果 应用软件程序可自动识别血管内膜及外膜的边界，血管及斑块的应变值大小可以彩色编码显示，并显示应变的三维分布，脂质型斑块应变值大于纤维型斑块（P〈0．05）。 结论 应用计算机应变软件程序可用于显示血管及斑块的应变分布，为进一步研究斑块的弹性提供了新方法。     

超声造影增强大鼠脑实质灰阶显像的实验研究

目的评价本科自制的“脂氟显”超声造影剂对大鼠脑实质的灰阶显像和增强效果。方法正常SD大鼠12只,经尾静脉弹丸式注入“脂氟显”(0.02ml/kg),大脑颞区超声扫查。采用相干造影成像(coherentcontrastimaging,CCI),大脑和嗅脑实质为感兴趣区,应用Photoshop软件分析造影前后图像,建立时间-强度曲线,测定各参数。结果造影后5s脑实质开始增强,大脑实质达峰时间分别为4、20min左右,持续增强20min以上,嗅脑6min达到峰值,持续增强8min,大脑实质较嗅脑增强时间长、效果更显著。目测评分10只达“ ”,2只为“ ”。造影后大脑及嗅脑的视频密度明显高于造影前,统计结果有显著差异。结论“脂氟显”超声造影能明显增强大鼠脑实质回声,持续时间长,有利于对脑血流灌注进行评价。     

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。     

诊断超声对大鼠胚胎脂质过氧化的近期和远期影响

本文观察了诊断超声辐照对大鼠胚胎脂质过氧化（ＬＰＯ）的近期和远期影响。将孕１３日龄（１３ＧＤ）鼠胚胎持续宫内超声辐照３０分钟，分别于孕１４、１６、１８及２１日龄取鼠胚胎或胎肝组织测定ＬＰＯ各指标，并与同孕龄对照组进行比较。结果表明：超声辐照后孕１４日龄鼠胚胎组织ＭＤＡ含量增加（Ｐ〈０．０５），ＳＯＤ活性降低（Ｐ〈０．０５），我们认为与超声空化产生的自由基、脂质过氧化有关。而上述改变在超声辐照后７２     

Time-Harmonic Ultrasound elastography of the Descending Abdominal Aorta: Initial Results

Stiffening of central large vessels is considered a key pathophysiologic factor within the cardiovascular system. Current diagnostic parameters such as pulse wave velocity (PWV) indirectly measure aortic stiffness, a hallmark of coronary diseases. The aim of the present study was to perform elastography of the proximal abdominal aorta based on externally induced time-harmonic shear waves. Experiments were performed in 30 healthy volunteers (25 young, 5 old, >50 y) and 5 patients with longstanding hypertension (PWV >10 m/s). B-Mode-guided sonographic time-harmonic elastography was used for measurement of externally induced shear waves at 30-Hz vibration frequency. Thirty-hertz shear wave amplitudes (SWAs) within the abdominal aorta were measured and displayed in real time and processed offline for differences in SWA between systole and diastole (ΔSWA). Data were analyzed using the Kruskal–Wallis test and receiver operating characteristic curve analysis. The change in SWA over the cardiac cycle was reduced significantly in all patients as assessed with ΔSWA (volunteers: mean = 10 ± 5 μm, patients: mean = 4 ± 1 μm; p < 0.001). The best separation of healthy volunteers from patients was obtained with a ΔSWA threshold of 4.7 μm, resulting in a sensitivity of 0.9 and a specificity of 1.0, with an overall area under the curve of 0.96. Time harmonic elastography of the abdominal aorta is feasible and shows promise for the exploitation of time-varying shear wave amplitudes as a diagnostic marker for aortic wall stiffening. Patients with elevated PWVs suggesting increased aortic wall stiffness were best identified by ΔSWA—a parameter that could be related to the ability of the vessel walls to distend on passages of the pulse wave.