超声组织定征:射频法与视频法的临床应用

超声组织定征 (ｕｌｔｒａｓｏｎｉｃｔｉｓｓｕｅｃｈａｒａｃｔｅｒｉｚａｔｉｏｎ ,ＵＴＣ)是指探讨组织声学特性与超声表现之间相互关系的基础与临床应用研究。目前 ,超声组织定征的研究范围包括声速、声衰减、声散射、回声强度、组织硬度、超声显微镜、超声与病理、超声组织定征在治疗学和组织声学造影中的应用、经验判断法、组织动态分析及其他相关方法等。较有发展前途和实用价值的是射频分析法的“超声背向散射积分 (ｉｎｔｅｇｒａｔｅｄｂａｃｋｓｃａｔｔｅｒ ,ＩＢＳ)”和视频分析法的“回声强度 (ｅｃｈｏｉｎｔｅｎｓｉｔｙ ,…     

超声组织定征的研究现状

随着超声诊断技术的不断深入发展，单纯的定性诊断已经远远不能满足临床的需要，超声定量分析技术的研究日益受到医学工程技术人员和超声工作者的重视。超声组织定征(ultrasonic tissue characterization UTC)是探讨组织结构的声学特性与超声声像图特征之间相互关系的一种基础与临床应用     

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。     

超声组织定征:射频法与视频法的临床应用进展

超声组织定征（ｕｌｔｒａｓｏｎｉｃ ｔｉｓｓｕｅ ｃｈａｒａｃｔｅｒｉｚａｔｉｏｎＵＴＣ）是指探讨组织声学特性与超声表现之间相互关系的基础与临床应用研究。目前,超声组织定征的研究范围有声速、声衰减、声散射、回声强度、组织硬度、超声显微镜、超声与病理、超声组织定征在治疗学和组织声学造影中的应用、经验判断法、组织动态分析及其他相关方法等。 较有发展前途和实用价值的是射频分析法的“超声背向散射积分（ｉｎｔｅｇｒａｔｅｄ ｂａｃｋｓｃａｔｔｅｒ ＩＢＳ）”和视频分析法的“回声强度（ｅｃｈｏ ｉｎｔｅｎｓｉｔｙ…     

心肌声学造影视频法与射频法定量分析方法比较研究

目的　比较超声组织定征视频法与射频法在心肌声学造影定量分析中的应用价值。方法　 8只开胸犬 ,经静脉滴注全氟显进行谐波触发显像 ,分别采用DFY型超声图像定量分析诊断仪和声学密度定量 (AD)技术获得心肌声学造影感兴趣区回声强度 (EI)和背向散射积分 (IBS)值 ,并绘制时间 强度曲线 (TIC)。结果　心肌缺血后 ,峰值回声强度 (PEI)、峰值背向散射积分值 (PIBS)降低 ,P值均 <0 .0 5 ;而达PEI及PIBS所需时间 (PT)延长 ,P值均 <0 .0 1。冠脉闭塞后 ,PEI及PIBS显著降低 ,P值均 <0 .0 1。结论　超声组织定征视频法与射频法均能用于心肌声学造影的定量分析 ,两者均能区分缺血与梗塞心肌。     

生物组织超声定征研究发展概况

一、概况 自七十年代末第一届国际超声组织定征会议以来,软组织超声定征研究,一直是人们关注的课题。十多年来,主要从以下三个方面进行组织定征的研究。 1.软组织声学特征参数测量法。 2.软组织频谱分析法。 3.软组织区域结构声特征模式辩识法。 近十多年来,国内外众多学者,分别从生物组织超声衰减系数、散射系数、非线性参量B/A值等进行了大量的实验研究(1982.D.Nicholas,1986,龚秀芬),并分析了声学参量与组织结构     

心脏超声组织定征的基础研究与临床应用进展

超声组织定征(Utrasonic Tissue Characterization UTC)是探讨组织声学特性与超声表现之间相互关系的基础与临床研究。它着重生物体本身的声学参数及结构参数与组织状态间的相互关系,寻求有效手段从超声信号中分离出能反应组织状态的参数,以作为区别不同组织、正常及异常组织鉴别病变性质的依据。从而探索新的超声诊断方法。     

超声组织定征的研究,应用进展

鉴于现有超声检测技术的局限性,促使人们进行超声组织定征(Ultrasonic tissuecharacterazation)的研究.目前广泛应用的超声检诊方法主要是了解组织的形态、位置及部分功能,其病理学特征不清楚.超声组织定征试图通过定量提取人体组织中的有用信息,并做出解释以达到识别各种正常和病理组织并对其进行鉴别和分析的目的;通过分析了解正、异常组织的病理、生理状况与组织声学参数和病理结果之间的关系,分析其形态学基础.由于超声通过组织的传输和反射特性的复杂性,超声和组织相互作用的机制尚不十分明了,人们只能从不同的方面来进行超声组织定征的探讨.此是其重要的研究方向,很有实用价值.     

冠心病不同状态血管和心肌组织超声组织定征研究进展

超声组织定征 (ｕｌｔｒａｓｏｎｉｃｔｉｓｓｕｅｃｈａｒａｃｔｅｒｉｚａｔｉｏｎ)是近年发展起来的一种无创性超声检测新方法 ,可对声像图进行量化检测 ,以期达到区别不同组织、正常及异常情况以及辨别病变性质、程度的目的。超声组织定征较有发展前途和实用价值的方法是射频法的“超声背向散射积分 (ｉｎｔｅｇｒａｔｅｄｂａｃｋｓｃａｔｔｅｒ ,ＩＢ)”和视频法的“回声强度 (ｅｃｈｏｉｎｔｅｎｓｉｔｙ ,ＥＩ)”[1,2 ] 。目前 ,冠心病的超声组织定征已成为超声组织定征研究的热点和发展方向。现就冠心病不同状态血管和心肌组织超声…     

背向散射超声心肌组织定征的研究进展

超声组织定征(ultrasonic tissue characterization,UTC)是评价超声表现和组织声学特性间相互关系的技术,除能观察脏器的大小、运动、相邻结构等变化外,还可以了解相关的组织细微病理改变,具有临床应用价值。背向散射参数测定技术是超声心肌组织定征研究中较为成熟的方法,与心肌生理、病理特性变化有较好的一致性,并可定量描述,对诊断心肌异常,如冠心病、高血压性和糖尿病性心肌病等心肌病理改变,有良好的应用前景。     

离体猪肝组织的高频超声成像研究

目的探讨高频超声成像在组织定征中的应用.方法用高频超声对猪的肝脏组织进行了成像和组织定征的研究,分析了正常和病变肝组织的图像和声参量的差异.结果高频背向散射系数较声速、声衰减更能反映组织结构的变化,高频超声图像具有高的分辨率.结论高频超声成像是生物组织定征的有效手段.     

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.     

Clinical potential of ultrasound tissue characterization in cardiomyopathies

Standard methods of echocardiographic analysis permit accurate categorization of cardiomyopathies into dilated, hypertrophic, and restrictive types. However, ascertainment of the cause of a particular cardiomyopathy (e.g., ischemia versus inflammation as the cause of a dilated myopathy) with ultrasound would be greatly facilitated by analysis of myocardial composition with ultrasound tissue characterization techniques. Qualitative observations have identified unusual echocardiographic image texture in hypertrophic cardiomyopathy and in amyloidosis. Quantitative observations have verified these findings and have identified increased ultrasound backscatter in regions of myocardial fibrosis, calcification, and anthracycline-induced cardiomyopathy. Although several technical problems remain unsolved and further research is needed in the mechanisms of normal and abnormal ultrasound/tissue interactions, tissue characterization with ultrasound has the potential to contribute independent information on myocardial composition in patients with cardiomyopathy.     

Echographic tissue characterization in diffuse parenchymal liver disease: correlation of image structure with histology

Seventy livers were examined in vitro using a computerized ultrasound B-mode data acquisition and analysis system. For tissue characterization, statistical parameters from pattern recognition algorithms describing image brightness and image structure were used. Reference classification based on histopathology as well as on chemical/morphometrical analysis led to the diagnostic classes of normal, fatty liver, fibrosis/cirrhosis and fatty fibrosis/cirrhosis. Comparing the two reference methods for ultrasound tissue characterization, reclassification based on chemical/morphometrical analysis resulted in a significant increase in diagnostic accuracy. The strong correlations between statistical ultrasound image parameters and morphometrical features reflect the relevance of our statistical approach to ultrasound tissue characterization.     

Spontaneous left atrial echocardiographic contrast in mitral stenosis: early disappearance after valve replacement.

We describe a patient with mitral stenosis and severely enlarged left atrium. Transthoracic echocardiography showed a false image of intraatrial thrombus, whereas transesophageal echocardiography showed massive spontaneous left atrial contrast. Intraoperative transesophageal echocardiography was performed. During cardioplegic arrest the contrast was enhanced, but it gradually and completely cleared 15 minutes after cardiopulmonary by-pass arrest. Transesophageal echocardiography is a useful technique for the study of intraatrial masses and may bring a new dimension to tissue characterization studies.     

Contrast Echocardiography for Assessment of Left Ventricular Thrombi

The diagnosis of intracardiac thrombi remains clinically relevant, with associated risks of systemic embolization and implications for antithrombotic management. Intravenously injected ultrasound contrast agents, composed of microbubbles smaller than red blood cells, have become established essential adjunctive tools for performance of state‐of‐the‐art echocardiography, providing important information on cardiac structure and function. Despite advances in other imaging modalities, echocardiography remains the initial tool for diagnosis and risk stratification in patients predisposed to developing cardiac thrombi. Ultrasound contrast agents are approved for left ventricular (LV) opacification and endocardial border definition. Additionally, the use of contrast echocardiography facilitates LV thrombus detection by providing contrast opacification within the cardiac chambers to clearly show the “filling defect” of an intracardiac thrombus. Furthermore, contrast perfusion echocardiography can provide an assessment of the tissue characteristics of LV masses suspicious for intracardiac thrombi and, by differentiating an avascular thrombus from a tumor, results in improved diagnostic performance of echocardiography. This article presents a clinical vignette highlighting the sound judgment of using contrast echocardiography to aid in the diagnosis of LV thrombi and will review recent advances in imaging modalities for intracardiac thrombus detection.     

Laser-generated focused ultrasound transducer using a perforated photoacoustic lens for tissue characterization

We demonstrate a laser-generated focused ultrasound (LGFU) transducer using a perforated-photoacoustic (PA) lens and a piezoelectric probe hydrophone suitable for high-frequency ultrasound tissue characterization. The perforated-PA lens employed a centrally located hydrophone to achieve a maximum directional response at 0° from the axial direction of the lens. Under pulsed laser irradiation, the lens produced LGFU pulses with a frequency bandwidth of 6–30 MHz and high-peak pressure amplitudes of up to 46.5 MPa at a 70-µm lateral focal width. Since the hydrophone capable of covering the transmitter frequency range (∼20 MHz) was integrated with the lens, this hybrid transducer differentiated tissue elasticity by generating and detecting high-frequency ultrasound signals. Backscattered (BS) waves from excised tissues (bone, skin, muscle, and fat) were measured and also confirmed by laser-flash shadowgraphy. We characterized the LGFU-BS signals in terms of mean frequency and spectral energy in the frequency domain, enabling to clearly differentiate tissue types. Tissue characterization was also performed with respect to the LGFU penetration depth (from the surface, 1-, and 2-mm depth). Despite acoustic attenuation over the penetration depth, LGFU-BS characterization shows consistent results that can differentiate the elastic properties of tissues. We expect that the proposed transducer can be utilized for other tissue types and also for non-destructive evaluation based on the elasticity of unknown materials.