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Evaluation of Progression of Arteriosclerosis by the Quantitative Assessment of Acoustic Tissue Characteristics Using Acoustic Microscopy

使用声学显微镜定量评估声学组织特征来评估动脉硬化的进展

基本信息

批准号：
05454273
负责人：
SENDA Shoichi
金额：
$ 4.29万
依托单位：
Kagawa Medical School
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

The aim of this study is to examine whether we can evaluate myocardial viability based on acoustic characteristics and elastic properties by measuring the ultrasonic attenuation, propagation velocity, and bulk modulus with a scanning acoustic microscopy. We investigated acoustic properties in ischemic myocardium such as stunned myocardium.The dogs were studied during 15 min of temporary LAD occlusion followed by 60 min of reperfusion. Myocardial specimens (stunned myocardium) which were obtained from endocardium in ischemic regin, were cut in 4 micron thickness, and prepared without paraffin on slide glass.1. We could not find any differences between iscemic myocardium (stunned myocardium) and normal using optical microscopy and electron microscopy. Using electron microscopy, only minimal swelling of the mitochondria and arcolemma was noted, with scattered evidence of mild cellular edema present in iscemic myocardium.2. Propagation velocity was 1656(]SY.+-[)36m/s in iscemic myocardium (stunned myocardium), and was 1657(]SY.+-[)8m/s in normal. There was no significant difference between them. Therefore, we considered that minimal changes in stunned myocardium produced no significant changes in acoustic properties.3. Furthermore, in order to evaluate the hardness of the ischemic myocardium, we use a new method to measure the bulk modulus and density of tissue specimen. We developed an acoustic cover membrane covering specimen in order to measure bulk modulus (Ks) and density (rhos) of specimen. This cover membrane is made of polycarbonate and is interposed between the specimen and the propagating medium. The intensity of the signal reflected from the cover membrane represents the acoustic impedance (Zs) of the specimen. So, if we measure Zs and Vs of specimen using the acoustic microscopy with this cover membrane, we can estimate Ks and rhos of specimen as follows ; Ks=ZsVs, rhos=Zs/Vs. In this way, we can evaluate the hardness of ischemic myocardium.

本研究的目的是通过扫描声学显微镜测量超声衰减、传播速度和体积模量，研究是否可以根据声学特性和弹性特性来评估心肌活力。研究了缺血心肌（如休克心肌）的声学特性。狗在15分钟的暂时LAD闭塞和60分钟的再灌注期间进行研究。心肌标本（休克心肌）取材于缺血区心内膜，切成4微米厚，在玻片上不加石蜡制备。在光学显微镜和电子显微镜下均未发现缺血心肌（休克心肌）与正常心肌有任何差异。电镜下，仅见线粒体和膜有轻微肿胀，局部心肌有轻度细胞水肿。传播速度为1656(]SY。缺血心肌（休克心肌）+-[)36m/s, 1657(]SY。+-[)正常情况下为8m/s。两者之间无显著差异。因此，我们认为休克心肌的微小变化不会引起声学特性的显著变化。此外，为了评估缺血心肌的硬度，我们采用了一种新的方法来测量组织标本的体积模量和密度。为了测量试样的体积模量（Ks）和密度（rho），我们研制了一种覆盖试样的声覆盖膜。这种覆盖膜是由聚碳酸酯制成的，并插入在试样和繁殖介质之间。覆盖膜反射的信号强度代表试样的声阻抗（Zs）。因此，如果我们用这种覆盖膜的声学显微镜测量试样的Zs和Vs，我们可以估计出试样的Ks和rho：Ks = ZsVs,罗斯= z / Vs。通过这种方法，我们可以评估缺血心肌的硬度。