Quantitative Assessment of Tissue Hardness of Coronary Artery Wall Specimens by Acoustic Tissue Characterization System with a Wide Band Frequency Ultrasound.

本研究的目的是开发一种声学组织表征系统，能够定量测量生物样本中的组织特征，并使用该系统评估组织硬度，特别是人体冠状动脉壁的硬度。1．我们开发了主要通过工作频率为 450MHz 的扫描声学显微镜 (HSAM-500S) 进行组织表征的定量测量系统。为了精确测量超声波的绝对传播速度，我们制作了一个新的样品台来安装样品，以精确调节样品厚度和目标样品环境的温度。我们能够通过读取干涉条纹位移图案来判断样品厚度的准确性，并确保样品周围环境的温度能够以*0.1ﾟC.2的精度进行控制。我们使用数字电压表来控制温度，检查了超声波传播速度与温度相关的变化。将 4 微米厚的肝脏、心肌和冠状动脉样本安装在正好 4 微米深的载物台上，然后测量不同受控温度下的传播速度。 30°C 至 50°C 之间的 3 个组织中传播速度随温度的增加率如下： 肝脏； 2.68m/s/ﾟC，心肌； 4.26m/s/ﾟC，冠状动脉（内膜）； 0.60m/s/℃。我们证实，根据样本的温度，三种组织中的传播速度明显不同，因此每种组织都具有与温度相关的声学特性。 3．我们测量了 13 名患有多种疾病的患者尸检获得的人体冠状动脉标本内膜中超声的绝对传播速度。根据光学显微镜对内膜的观察结果，我们将这些标本分为三组：正常、早期硬化和晚期硬化。 25℃时超声波传播速度如下：正常； 1947.3*100.2m/s，早期； 1694.3*64.1m/s，高级阶段； 2246.3*96.0m/秒。一般来说，传播速度越快，组织越硬。因此，我们得出结论，与正常组织相比，疾病早期阶段的光学定义的硬化内膜组织显示出最初的软化，随后随着钙化的进展而硬化。4。为了通过 10-100MHz 超声波对生物样本中的组织特征进行定量评估，我们正在进行新系统的开发和实验研究，以测量由于组织吸收超声波而产生的衰减，例如。血液或冠状动脉，使用50MHz超声系统。较少的

The aim of this study was to develop an acoustic tissue characterization system able to quantitatively measure tissue characteristics in biological specimens, and to evaluate tissue hardness, especially of the human coronary artery wall, using this system.1. We developed the quantitative measurement system for tissue characterization mainly from a scanning acoustic microscope(HSAM-500S) operating at 450MHz. To precisely measure the absolute propagation velocity of ultrasound, we made a new stage for mounting specimens to precisely regulate both specimen thickness and temperature of the objective specimen environment. We were able to judge the accuracy of the specimen thickness by reading patterns of the interference fringe shift, and also ensure that the temperature of the environment around the specimen could be controlled with an accuracy of *0.1ﾟC.2. We examined temperature-dependent changes in the propagation velocity of ultrasound using a digital voltmeter for controlling temperat … More ure. 4-micron-thick specimens of liver, myocardium and coronary artery were mounted on a stage of exactly 4 microns depth, after which we measured propagation velocities at various controlled temperatures. The rates of increase in propagation velocity with temperature in the 3 tissues between 30ﾟC and 50ﾟC were as follows : liver ; 2.68m/s/ﾟC, myocardium; 4.26m/s/ﾟC, coronary artery (intima) ; 0.60m/s/ﾟC. We confirmed that propagation velocity varied distinctly in each of the 3 tissues according to the temperature of the specimen, and that therefore each tissue had temperature-dependent acoustic characteristics.3. We measured the absolute propagation velocity of ultrasound in the intima of human coronary artery specimens obtained by autopsy from 13 patients with a variety of diseases. On the bases of findings in the intima with an optical microscope, we classified these specimens into 3 groups; normal, early stages of scleroses, and advanced stages of sclerosis. Ultrasound propagation velocity at 25ﾟC was as follows : normal; 1947.3*100.2m/s, early stage; 1694.3*64.1m/s, advanced stage; 2246.3*96.0m/s. Generally, the faster the propagation velocity, the harder the tissue. We therefore concluded that optically defined sclerotic intima tissue in early stages of disease showed an initial softening as compared with normal tissue, and this was followed by subsequent hardening with advancing calcification.4. As quantitative assessment of tissue characteristics in biological specimen by 10-100MHz ultrasound, we were getting on with the development of a new system and the experimental study to measure the attenuation due to absorption of ultrasound through the tissue, ex. blood or coronary artery, using 50MHz ultrasound system. Less