犬缺血再灌注心肌靶向超声造影图像的组织定征量化研究

目的用超声组织定征量化分析白细胞靶向超声造影剂对犬心肌缺血再灌注(ischemia-reperfusion,I-R)损伤声像图。方法将自制超声微泡造影剂"表活显"(self-madesurfactantfluorocarbon-filledmicrobubbles,SFCMB)与磷脂酰丝氨酸(phosphatidylserine,PS)结合,制备成白细胞靶向超声微泡造影剂(SFCMB-PS),在实时心脏超声造影条件下,用SFCMB-PS对9只犬心肌I-R模型进行延迟心肌显像。实验结束后,在心肌I-R损伤处取组织块立即进行髓过氧化物酶(myeloperoxidase,MPO)活性测定。超声组织定征定量分析缺血再灌注损伤心肌。结果I-R损伤心肌声像图的回声强度[(22.56±4.62)GS]明显增高,与正常心肌[(16.57±3.82)GS]和缺血心肌[(5.00±2.58)GS]比较,差异均有统计学意义(P<0.01),而且其与MPO活性有良好的相关关系(r=0.776,P<0.05)。结论超声组织定征定量分析缺血再灌注心肌靶向超声显像能够较准确、客观地反映再灌注损伤的严重程度。     

超声造影剂对犬缺血再灌注心肌的靶向显像及其机制研究

目的用自制的靶向超声造影剂实现无创性地评价犬心肌缺血再灌注,同时研究其靶向性作用机制。方法将自行研制的表面活性剂超声造影剂“表活显”(surfactantfluorocarbon-filledmicrobubbles,SFCMB)与磷脂酰丝氨酸(phosphatidylserine,PS)结合,制备成靶向超声造影剂(SFCMB-PS),在实时心肌超声造影(MCE)条件下,用SFCMB-PS对犬心肌缺血再灌注模型进行延迟心肌显像。流式细胞术测定白细胞激活前和激活后与SFCMB-PS的结合情况以及在补体和β2整合素中的Mac-1缺乏时激活的白细胞与SFCMB-PS的结合情况。结果延迟心肌显像表明缺血再灌注区的造影剂回声较正常区的回声明显增强。流式细胞术证明了PS结合在造影剂微泡的表面,未激活的白细胞与微泡的结合率为(5.27±0.75)%,激活的白细胞与微泡的结合率为(39.67±6.83)%,结合率明显提高(P<0.01);补体和β2整合素中的Mac-1缺乏时,两者的结合明显受到抑制,结合率降到(12.27±1.66)%(P<0.01)和(10.90±2.40)%(P<0.01)。结论SFCMB-PS可以无创性地评价缺血再灌注损伤心肌的部位及其严重程度。SFCMB-PS是通过β2整合素中的Mac-1和补体介导途径与激活的白细胞结合并进入细胞内的。     

白细胞靶向超声造影显像无创评价犬心肌缺血再灌注损伤

目的 用白细胞靶向超声造影剂无创评价犬心肌缺血再灌注（ischemia-reperfusion，I-R）损伤的范围及严重程度。 方法 将自制“表活显”（self-made surfactant fluorocarbon-filled microbubbles，SFCMB）与磷脂酰丝氨酸（phosphatidylserine，PS）结合，制备成白细胞靶向超声造影剂（SFCMB-PS），在实时心脏超声造影（myocardial contrast echocardiography，MCE）条件下，用SFCMB-PS对9只犬心肌I-R模型进行延迟心肌显像。实验结束后，在心肌I-R损伤处取组织块立即进行髓过氧化物酶（myeloperoxidase，MPO）活性测定。 结果 延迟心肌显像可见缺血心肌部位有明显充盈缺损，而再灌注后心肌的造影剂回声明显增强。定量分析结果表明I-R损伤心肌部位声像图的灰阶强度与MPO活性有明显的相关关系（r=0．776，P〈0．05）。 结论 用白细胞靶向超声造影剂评价心肌I-R损伤有明显的临床价值。     

超声组织定征视频法监控兔缺血再灌注肾靶向声学造影实验研究

目的定量评价自制靶向超声造影剂对兔缺血再灌注肾显像的靶向增强效果。方法将磷脂酰丝氨酸(phos-phatidylserine,PS)加在自制表面活性剂类超声造影剂微泡壁上,用有和无PS造影剂分别对6只肾缺血再灌注损伤兔进行声学造影,谐波显像观察肾实质回声的变化,用国产“DFY-2型超声图像定量分析诊断仪”对兔肾实质灰阶(GS)值进行动态定量分析。结果造影后,有和无PS组GS峰值分别高于造影前(P<0.001和P<0.05);有PS组GS峰值高于无PS组(P<0.001)。结论超声组织定征视频法可定量评价兔缺血再灌注肾靶向声学造影的增强效果。     

双靶向超声微泡造影剂评价小鼠缺血再灌注心肌

目的 制备同时携载P选择素和ICAM-1抗体的靶向超声微泡造影剂,以评估小鼠缺血再灌注损伤心肌声学造影显像效果.方法 采用生物素-亲和素方法制备靶向微泡,于激光共聚焦显微镜下观察微泡形态,流式细胞仪检测连接效率.将24只健康昆明小鼠随机分成3组:结合双抗体选择素微泡组(MBd组)10只、结合P选择素单抗组(MBp组)10只,空白微泡组(MBc组)4只.结扎冠状动脉左前降支近左主干分支,制作心肌缺血再灌注模型,60 min后经尾静脉分别注射MBd、MBp及MBc,采集心肌对比造影图像.所有图像均采用Sonomath超声影像分析仪处理.结果 MBd组和MBp组对缺氧内皮细胞的黏附力以及对缺血再灌注区心肌显像增强程度显著高于MBc组(P均＜0.05),MBd组对缺血再灌注区心肌显像延迟时间高于MBp组(P＜0.05).结论 双靶向微泡联合超声造影是检测和评估小鼠缺血再灌注心肌的无创性手段.     

携抗P-selectin靶向超声造影剂犬体内超声分子成像

目的 制备携抗P-selectin靶向超声造影剂,探讨其评价心肌缺血再灌注损伤的超声分子成像效果。方法 采用“生物素-亲和素”桥接法制备携抗P-selectin靶向超声造影剂,建立犬心肌缺血再灌注模型,分别注入携抗P-selectin靶向超声造影剂（MBp）和空白超声造影剂（MBc）,行心肌声学造影检查,采图、存盘。应用DFY型超声图像定量分析诊断仪中的彩色编码技术对存储的图像进行脱机处理,观察MBp体内超声分子成像效果。结果 成功制备携抗P-selectin靶向超声造影剂及建立犬心肌缺血再灌注模型。彩色编码图像示MBp行心肌声学造影可见缺血再灌注区心肌显著增强;MBc于缺血再灌注区心肌造影无明显增强。结论 应用携抗P-selectin靶向超声造影剂行心肌声学造影检查能准确检测再灌注治疗后犬心肌缺血再灌注损伤。     

心肌再血管化机制的对比实验研究

目的观察研究钬激光和True-cut活检针心肌再血管化近、远期的机制和效果。方法利用经静脉注射造影剂对犬缺血心肌模型进行心肌超声微泡造影。结果部分结扎犬的冠状动脉前降支,建立缺血模型后,缺血区超声微泡密度明显降低,分别用2种方法再血管化后,2组犬缺血区超声微泡密度较缺血时均明显增加,接近其缺血前的微泡密度;再血管化区超声微泡较其他部位提前显影。远期超声微泡检查显示心肌灌注较急性缺血时也有一定改善。结合组织学方法发现,远期心肌灌注的改善得益于隧道周围新生循环结构如心肌窦和新生血管的增加。结论钬激光和True-cut活检针隧道均可即刻使缺血心肌灌注改善,并逐渐闭塞,新生循环结构使缺血区得到有限的灌注。应用新一代经静脉注射造影剂超声心肌微泡造影结合组织学方法可作为研究心肌再血管化机制的可靠手段。     

二次谐波触发显像声学造影评价急性心肌缺血的实验研究

目的　采用二次谐波触发显像超声造影评价急性缺血心肌血流灌注。方法　对 10只犬急性心肌缺血模型用自制的白蛋白氟碳气体声学造影剂进行心肌声学造影 ,测量心肌灌注缺损面积 ,与心肌病理染色对照。结果　造影后正常心肌回声显著增强。缺血心肌呈现灌注缺损。缺损面积与心肌病理染色测值相关良好。结论　自制的声学造影剂安全有效 ,能用于动物心肌缺血的实验研究。     

心肌再血管化机制的对比实验研究

目的观察研究钬激光和True-cut活检针心肌再血管化近、远期的机制和效果。方法利用经静脉注射造影剂对犬缺血心肌模型进行心肌超声微泡造影。结果部分结扎犬的冠状动脉前降支，建立缺血模型后，缺血区超声微泡密度明显降低，分别用2种方法再血管化后，2组犬缺血区超声微泡密度较缺血时均明显增加，接近其缺血前的微泡密度；再血管化区超声微泡较其他部位提前显影。远期超声微泡检查显示心肌灌注较急性缺血时也有一定改善。结合组织学方法发现，远期心肌灌注的改善得益于隧道周围新生循环结构如心肌窦和新生血管的增加。结论钬激光和True-cut活检针隧道均可即刻使缺血心肌灌注改善，并逐渐闭塞，新生循环结构使缺血区得到有限的灌注。应用新一代经静脉注射造影剂超声心肌微泡造影结合组织学方法可作为研究心肌再血管化机制的可靠手段。     

超声靶向微泡破坏技术评价心肌缺血再灌注损伤的研究进展

心肌缺血再灌注损伤是指原缺血心肌恢复血供后发生更为严重的损伤,再灌注损伤减弱了再灌注给机体带来的益处。心肌缺血再灌注损伤在靶向超声分子显像技术中有多种研究,包括超声靶向破坏微泡技术对心肌缺血再灌注的评价与介导靶向治疗,其中携IL-8单克隆抗体的超声靶向微泡破坏技术可明显减轻再灌注后炎症反应引起的损伤,减轻心肌坏死程度。     

自制氟碳声学造影剂心肌造影安全性实验研究

目的:研究自制的氟碳声学造影剂的安全性。方法:采用谐波触发显像及心内插管对实验犬进行心肌声学造影,观察血流动力学变化,并进行多脏器病理检查。结果:实验中,犬生命征平稳。心肌回声增强,血流动力学无变化,病理检查未见异常改变。结论:自制的氟碳声学造影剂安全、有效,可用于动物实验研究。     

超声微泡造影剂在疾病诊断与治疗中的研究进展

超声微泡造影剂在疾病诊断与治疗中的作用日渐明显.超声微泡造影剂可用于对心脏、肝脏、肿瘤等的声学造影诊断,具有靶向性的超声微泡造影剂对组织、血栓及肿瘤的靶向显影应用前景广阔.目前的研究表明,超声微泡造影剂在治疗中也显示出巨大潜力,可作为一种有效的基因或药物运载工具.而低功率超声辐射微泡治疗肿瘤研究亦有望取得突破性进展.     

心肌声学造影的研究进展及应用

随着对心肌声学造影(MCE)技术的深入研究,MCE成像质量及稳定性得到逐步提高。MCE是用于评价心肌微循环灌注的技术,其通过分析心肌血流灌注能准确评估心肌血流量,诊断急性及慢性缺血性心脏病的病变范围及程度,评价再灌注治疗后心肌存活性及收缩功能恢复情况。MCE的研究领域扩展到基因治疗方面,可为心血管疾病的诊断和治疗提供新途径。     

Real-time myocardial blood flow imaging in normal human beings with the use of myocardial contrast echocardiography.

Triggered myocardial contrast echocardiography (MCE) has been used successfully to quantify myocardial blood flow and assess coronary stenosis in animal models, but practical considerations have limited its broad clinical use. Real-time MCE may have practical advantages to assess perfusion and real time myocardial blood flow in human beings. We compared real-time MCE with triggered imaging in 23 normal human volunteers by using an investigational ultrasound contrast agent (DMP-115) and a commercially available ultrasound platform (Acuson Sequoia). Peak myocardial opacification (reflecting myocardial blood volume) after contrast infusion was quantified digitally in gray scale units (GU). In 13 subjects, myocardial blood flow reserve was assessed during dipyridamole infusion with the use of intermittent destruction-replenishment techniques. Real-time MCE resulted in a 30- to 45-GU increase from baseline compared with a 20- to 70-GU increase with triggered imaging. Real-time MCE showed no statistical difference in opacification (P = .131 by analysis of variance) among any of the myocardial regions of interest. Triggered imaging resulted in heterogeneous opacification among the regions of interest (P < .05 by analysis of variance). Dipyridamole did not significantly change peak myocardial opacification (myocardial blood volume) for either technique. Quantification of flow reserve revealed that myocardial blood flow reserve for the dipyridamole group was 3.6 +/- 0.4 (mean +/- 1 standard error of the mean). Real-time MCE is feasible in normal human volunteers and provides homogenous opacification of the myocardium. Furthermore, quantification of myocardial blood flow with real-time MCE in normal human beings produces results that are consistent with the known physiology of the coronary microcirculation.     

Impact of myocardial contrast echocardiography on vascular permeability: an in vivo dose response study of delivery mode, pressure amplitude and contrast dose

An in vivo rat model of myocardial contrast echocardiography (MCE) was defined and used to examine the dose range response of microvascular permeabilization and premature ventricular contractions (PVCs) with respect to method of imaging, peak rarefactional pressure amplitude (PRPA) and agent dose. A left ventricular short axis view was obtained on anesthetized rats at 1.7 MHz using a diagnostic ultrasound system with simultaneous ECG recording. Evans blue dye, a marker for microvascular leakage, and a bolus of Optison were injected i.v. Counts of PVCs were made from video tape during the 3 min of MCE. Hearts were excised 5 min after imaging and petechial hemorrhages, Evans blue colored area and Evans blue content were determined. No PVCs or microvascular leakage were seen in rats imaged without contrast agent followed by contrast agent injection without imaging. When PVCs were detected during MCE, petechial hemorrhages and Evans blue leakage were also found in the myocardium. Triggering 1:4 at end-systole produced the most PVCs per frame and most microvascular leakage, followed by end-systole 1:1, continuous scanning and end-diastole triggering 1:1. All effects increased with increasing Optison dosage in the range 25 to 500 microL kg(-1). Ultrasound PRPA was important, with apparent thresholds for PVCs at 1.0 MPa and for petechiae at 0.54 MPa. PVCs, petechial hemorrhages and microvascular leakage in the myocardium occur as a result of MCE in rats.     

Noninvasive vessel-selective perfusion imaging with intravenous myocardial contrast echocardiography.

BACKGROUND: Intravenous myocardial contrast echocardiography (MCE) cannot identify each perfusion area of coronary vessels separately. However, by destroying microbubbles passing through a specific vessel using high-power ultrasound during intravenous MCE, vessel-selective perfusion imaging (VSPI) may be feasible. METHODS: In 10 open-chest dogs, intermittent short-axis images were obtained during contrast agent infusion using an ultrasound system. For VSPI, a probe coupled to another ultrasound machine was placed on the proximal left circumflex coronary artery (LCx). High-power ultrasound pulses were transmitted to destroy bubbles passing through the LCx. A negative contrast area on VSPI was considered to represent the perfusion area of the LCx (LCx-VSPI). A negative contrast area on conventional MCE during LCx occlusion and a region without staining by Evans blue dye were used as gold standards for defining the LCx perfusion area. LCx-VSPI was compared with a negative contrast area on conventional MCE during LCx occlusion and a region without staining by Evans blue dye. RESULTS: Despite lack of LCx occlusion, high-power destructive pulses produced a definite area of negative contrast on the LCx region. Decreased power of ultrasound pulses resulted in disappearance of the negative contrast area. An excellent relationship was demonstrated between both LCx-VSPI and a negative contrast area on conventional MCE during LCx occlusion (r = 0.93, P <.0001), and LCx-VSPI and a region without staining by Evans blue dye (r = 0.92, P =.0002). CONCLUSION: VSPI during intravenous MCE may be feasible for noninvasive assessment of perfusion areas associated with specific vessels.     

携Sialyl Lewis^X超声微泡靶向探查缺血心肌的炎症分子“印记”

目的探讨应用靶向超声分子成像探查心肌缺血再灌注损伤炎症“印记”的可行性。方法采用“亲和素-生物素”桥接法构建携唾液酸化路易斯（Sibyl Lewis^X）靶向超声微泡（MBsLex）和同型对照微泡（MBc）。10只心肌缺血再灌注小鼠随机先后注入MBsLex和MBc（间隔30min）,分别于注入5min后行心肌对比超声检查,测量心肌缺血区和非缺血区的声强度（Ⅵ）。结果对比超声图像显示MBsLex组缺血区心肌造影见显著增强,Ⅵ值高达23．52±1．08,而在MBc组缺血区心肌造影仅见轻度增强,Ⅵ缸为9．81±0．41,两者之间差异有统计学意义（P〈0．05）。但无论MBsLex组还是MBc组,缺血区心肌Ⅵ值均明显高于非缺血区心肌Ⅵ值（P〈0．05）。两组非缺血区心肌之间Ⅵ值未见明显差异。结论应用携sLex超声微泡行对比超声能够靶向探查心肌缺血再灌注损伤的炎症“印记”。