医学超声内窥镜下的脉冲多普勒血流检测

多普勒超声技术在医学超声成像系统中的应用进一步扩大超声诊断的范围。本文提出一种在超声内窥镜成像系统中用于血流参数定量分析脉冲多普勒信号处理方案,经过编码激励与脉冲压缩、正交解调、低通滤波、FFT等最终显示血流速度频谱图。文中给出电路和仿真结果,输出结果正确,已可以实现对多普勒频率的测量。     

基于超超声造影剂谐波图像的流场测量技术

本文研究了基于超声造影剂的血流运动场估计与显示技术,通过在血液中注入超声造影剂作为示踪粒子,对造影谐波图像进行时域相关处理,可得到成像部位的二维流场分布图。     

脉冲多普勒超声血流定量测量的误差分析及新技术展望

脉冲多普勒超声作为一种临床辅助诊断技术,广泛应用于血流的定量测量。但由于该技术直接得到的是沿超声传播方向的速度分量,实际测量时需要角度校正,因此容易产生误差。本文根据脉冲多普勒的计算方法和实现原理,从超声系统、算法和临床操作等多个方面详细阐述了脉冲多普勒超声定量测量可能产生的误差。重点对角度校正产生的误差做了详细的定量分析,并结合超声血流成像中的最大可测量速度、成像深度、发射信号的中心频率等多个相关参数,提出了避免或者减少误差的方法。最后指出一种可以避免这类误差但还未在临床上广泛使用的新技术,即超声向量血流成像。文章描述了这种新技术与传统脉冲多普勒的区别,介绍了新技术对于非层流定量测量的优势,并从临床的角度对向量血流成像当前问题和未来发展给出的意见和建议。     

光声血流速度测量方法及研究进展

光声成像因其独特的成像原理,兼顾了功能性和分辨率,对诊断和处理心血管疾病具有十分重要的意义。通过对光声血流速度测量进行综述,系统介绍了光声多普勒、光声显微成像和光声相关谱三个原理下的血流速度测量原理及具体应用,以期对此领域的研究人员的研究提供参考。     

乳腺肿瘤红外热成像及其与超声影像的比较

采用红外热成像系统联合彩色多普勒超声仪对8例女性乳腺肿瘤患者进行扫描成像,获取乳腺肿瘤温度分布等红外热辐射特征及其乳腺肿瘤的大小、内部血流等超声影像特征,探讨乳腺肿瘤的红外热图像特征,同时将红外热图像分析结果与超声诊断结果进行比较,结果表明两种影像技术的吻合度较好,研究结果具有重要的应用价值。     

基于超声造影剂谐波图像的流场测量技术

本文研究了基于超声造影剂的血流运动场估计与显示技术,通过在血液中注入超声造影剂作为示踪粒子,对造影谐波图像进行时域相关处理,可得到成像部位的二维流场分布图。相对于常规Ｄｏｐｐｌｅｒ方法中用Ｄｏｐｐｌｅｒ回波信号的频偏计算流速值,该技术可直接从超声图像提取与夹角无关的流速矢量信息。本文通过流动模型验证该方法,浸入超声水槽中的乳胶管中流动着血液替代品,沿水流方向进行超声成像,对实验所得的造影后的Ｂ超图像以及谐波图像,用一种节省计算量的多尺度相关算法进行处理,并相互比较。结果显示,谐波图像相对Ｂ超基波图像具有更高的信杂比,从根本上解决了基波图像低信噪比对时域相关测量精度的限制,可以得到与夹角无关的二维血流场分布图,该方法是医学和有关工业领域中超声流场测量的一种有效的方法。     

一种联合光声与激光散斑的多模态成像系统研究

多模态成像技术是近年生物医学成像领域的研究方向之一,它能够结合不同模式的成像,解决单一成像模式的不足。论文设计并搭建了一套基于光声成像与激光散斑成像的多模态成像系统,通过对头发光声成像和对血流样品激光散斑成像的模拟实验,验证了系统的可行性,测得光声成像分辨率为40 μm,激光散斑成像血流速度分辨率为0.2 mm/s。通过在体实验实现了对小鼠耳朵血管损伤的连续7天检测,分析血管损伤和修复情况。该系统有效的结合了高分辨率光声成像技术与激光散斑血流成像技术,对新型的多模态光声成像系统研究具有重要意义。     

超声彩色血流成像中基于动态区域划分抑制杂波的方法

为提高超声彩色血流成像质量,提出了一种基于动态区域划分的杂波抑制方法。先根据超声回波信号的幅度对血流与组织区域作出初步的划分,再根据杂波运动的非平稳性对组织区域作进一步的调整,最后对各区域用特征向量滤波器进行杂波抑制。将本方法用于计算机仿真血流信号和人体实测血流数据,结果表明:本方法在有效抑制非平稳杂波的同时,能较好地保持血流流速剖面的完整性,解决了传统均匀分段特征向量滤波器选取区间长度时的矛盾,有望成为超声彩色血流成像中一种有效的杂波抑制方法。     

三维超声成像在乳腺肿块诊断中应用价值

目的探讨三维超声成像技术对乳腺肿块的诊断价值。方法以我院2010年1月~2012年6月收治的60例女性患者为研究对象,所有患者均行二维、三维超声检查,对比2种检查方式的诊断准确率及检出率。结果超声诊断结果与手术及穿刺病理结果进行对照,60例患者共71个肿块。二维超声对59个乳腺肿块诊断正确,诊断准确率为83.1%(59/71),三维超声对68个乳腺肿块诊断正确,诊断准确率为95.8%(68/71),三维超声诊断准确率率高于二维超声,差异有统计学意义(P<0.05)。二维超声血流检出率63.41%(26/41),三维超声血流检出率97.56%(40/41),三维超声血流检出率高于二维超声血流检出率,差异有统计学意义(P<0.05)。结论三维超声诊断乳腺肿块准确率和血流检出率高于二维超声,使用三维超声可提高乳腺肿块鉴别诊断水平。     

彩色多普勒超声与瞬时弹性成像诊断乙肝后肝硬化的价值研究

彩色多普勒超声检查与瞬时弹性成像技术是诊断乙肝后肝硬化的无创检查。彩色多普勒超声可通过肝脏形态、门静脉血流动力学与半定量评分对乙肝后肝硬化进行诊断,瞬时弹性成像可通过肝脏硬度值对肝硬化进行诊断。本文主要综述了目前彩色多普勒超声是如何对肝硬化进行诊断以及其在临床上的诊断应用、瞬时弹性成像是如何对肝硬化进行诊断以及其在临床上的诊断应用,二者联合诊断肝硬化的临床应用等方面,对肝硬化的诊断提供一定的参考意义,以期指导临床治疗。     

Immune response by host after allogeneic chondrocyte transplant to the cartilage

We discovered adrenomedullin (AM) from human pheochromocytoma tissue by monitoring the elevating activity of intracellular cyclic AMP (cAMP) in rat platelets in 1993. Since the discovery of AM, it has attracted intense interest from cardiovascular researchers because AM elicits multiple biological activities, including a potent and powerful hypotensive activity caused by dilatation of resistance vessels. AM is biosynthesized and secreted from tissues, including cardiovascular organs. In addition to AM, "proadrenomedullin N-terminal 20 peptide (PAMP)," another biologically active peptide, was found to be processed from the AM precursor. Plasma AM levels are increased in various cardiovascular and renal diseases. AM, therefore, seems to function as a novel system that controls circulation and body fluid, and may be involved in pathophysiological changes in cardiovascular diseases. Therefore, in this review we will focus on the structure of AM and its gene, distribution, receptor, and the physiological and pathological roles of AM in cardiovascular disease.     

Immunocytochemical analysis of connexin expression in the healthy and diseased cardiovascular system

Gap junctions play essential roles in the normal function of the heart and arteries, mediating the spread of the electrical impulse that stimulates synchronized contraction of the cardiac chambers, and contributing to co-ordination of activities between cells of the arterial wall. In common with other multicellular systems, cardiovascular tissues express multiple connexin isotypes that confer distinctive channel properties. This review highlights how state-of-the-art immunocytochemical and cellular imaging techniques, as part of a multidisciplinary approach in gap junction research, have advanced our understanding of connexin diversity in cardiovascular cell function in health and disease. In the heart, spatially defined patterns of expression of three connexin isotypes-connexin43, connexin40, and connexin45-underlie the precisely orchestrated patterns of current flow governing the normal cardiac rhythm. Derangement of gap junction organization and/or reduced expression of connexin43 are associated with arrhythmic tendency in the diseased human ventricle, and high levels of connexin40 in the atrium are associated with increased risk of developing atrial fibrillation after coronary by-pass surgery. In the major arteries, endothelial gap junctions may simultaneously express three connexin isotypes, connexin40, connexin37, and connexin43; underlying medial smooth muscle, by contrast, predominantly expresses connexin43, with connexin45 additionally expressed at restricted sites. In normal arterial smooth muscle, the abundance of connexin43 gap junctions varies according to vascular site, and shows an inverse relationship with desmin expression and positive correlation with the quantity of extracellular matrix. Increased connexin43 expression between smooth muscle cells is closely linked to phenotypic transformation in early human coronary atherosclerosis and in the response of the arterial wall to injury. Current evidence thus suggests that gap junctions in both their guises, as pathways for cell-to-cell signaling in the vessel wall and as pathways for impulse conduction in the heart, contribute to the initial pathogenesis and eventual clinical manifestation of human cardiovascular disease.     

多联动机构运动仿真

介绍了CAD/CAE/CAM一体化软件UG机构学(Mechanisms)模块的功能。通过机构运动模块在心血管造影机设计中的应用,实现了多联动机构的运动学分析仿真,精确描述复合运动体空间运动,并进行了干涉检查,为设计提供一种科学依据。     

Fabrication of affordable pulse duplication system for the in-vitro cardiovascular experiments based on gear pump and orifice flowmeter

Journal of Mechanical Science and Technology - More than 18 millions of people are still suffering from cardiovascular diseases (CVD) globally. Although various hemodynamics features are known to...     

Hydraulic analogs of the obliterative atherosclerosis of blood vessels

Capillary obliteration, filtration in a porous body, and other analogs of the obliterative atherosclerosis of blood vessels are considered. On that basis, new methods of addressing cardiovascular diseases may be developed.     

酸碱失衡与急性心血管疾病关系研究进展

急性心血管疾病作为内科常见疾病,病情进展快,病理变化复杂,常出现体内酸碱平衡紊乱,酸碱失衡尤其见于急性心肌梗死疾病中。临床研究表明,体内酸碱失衡可能会导致急性心血管系统损伤,影响疾病的预后,甚至导致心源性休克发生,因此各项酸碱监测指标对于急性心血管疾病的诊断、治疗监测和预后有着重要临床作用。     

Empirical Mode Decomposition and Principal Component Analysis implementation in processing non-invasive cardiovascular signals

Biomedical signals are relentlessly superimposed with interferences. The nonlinear processes which generate the signals and the interferences regularly exclude or limit the usage of classical linear techniques, and even of wavelet transforms, to decompose the signal.Empirical Mode Decomposition (EMD) is a nonlinear and adaptive technique to decompose data. Biomedical data has been one of its most active fields. EMD is fully data-driven, thus producing a variable number of modes. When applied to cardiovascular signals, the modes expressing cardiac-related information vary with the signal, the subject, and the measurement conditions. This makes problematic to reconstruct a noiseless signal from the modes EMD generates.To synthesize and recompose the results of EMD, Principal Component Analysis (PCA) was used. PCA is optimal in the least squares sense, removing the correlations between the modes EMD discovers, thus generating a smaller set of orthogonal components. As EMD-PCA combination seems profitable its impact is evaluated for non-invasive cardiovascular signals: ballistocardiogram, electrocardiogram, impedance and photo plethysmogram.These cardiovascular signals are very meaningful physiologically. Sensing hardware was embedded in a chair, thus acquiring also motion artefacts and interferences, which EMD-PCA aims at separating. EMD is seen to be important, because of its data adaptability, while PCA is a good approach to synthesize EMD outcome, and to represent only the cardiovascular portion of the signals.     

探讨高血压合并冠心病患者动态血压与心电图的相关性

目的探讨高血压合并冠心病患者的血压波动与ST-T改变及心律失常发生的相关性。方法对88例高血压和/或冠心病患者进行分组研究,其中高血压合并冠心痛组25例,高血压无并发症组28例.冠心病组35例,所有患者均同步监测24h动态血压(ABPM)和动态心电图(DCG),观察不同组血压波动与ST-T改变和心律失常发生的相关性并进行对照分析。结果 ABPM与DCG同步检出高血压合并冠心痛组血压变化与ST-T改变和心律失常发生率为88%,明显高于高血压无并发症组42.9%和冠心病组65.7%,表明高血压合并冠心痛患者血压变化与ST-T改变及心律失常有关联。结论 ABPM与DCG同步检测有助于鉴别血压变化与心脏的关系,对预防心血管事件的发生具有积极的临床意义。     

分子影像技术活体追踪移植干细胞的研究进展

干细胞具有分化、再生能力,通过体外扩增和体内移植,可以治疗各种组织坏损和退化性疾病(如心脑血管疾病、脑脊髓外伤和糖尿病等),具有极大的应用前景,是目前国际、国内的研究热点。利用核素显像、磁共振成像和光成像等分子影像技术,通过体外直接标记、报告基因或功能显示等追踪策略,可以显示干细胞在活体内的分布和变化,明确其最终归宿和产生的功能。合理选择这些分子影像技术和追踪策略,或通过互补结合,将有助于阐明干细胞在活体内的作用机制和相关的影响因素,指导临床干细胞治疗抉择和疗效评估。     

血管硬度无创检测的新方法

血管硬度是检测亚临床动脉硬化的一个有效的参数,能够很好的表征人体的心血管健康状况。血管弹性扩张系数ETK是心脏收缩排血时动脉血管弹性扩张的程度,通常用来作为计算其它心血管参数的中间变量,本文提出应用ETK直接来评价动脉血管硬化的程度的方法,设计和开发了血压与血管硬度的无创检测系统。临床实验结果表明,血管弹性扩张系数ETK与临床彩超检测结果的相关系数为0.76,证明了该方法的有效性。