Palanchon Peggy, Bouakaz Ayache, Klein Jan, de Jong Nico
Department of Cardiology, Thoraxcentre, Erasmus Medical Center Rotterdam, 3000 DR Rotterdam, The Netherlands.
IEEE Trans Biomed Eng. 2005 Dec;52(12):2087-92. doi: 10.1109/TBME.2005.857641.
The classification of circulating microemboli as gaseous or particulate matter is essential to establish the relevance of the detected embolic signals. Until now, Doppler techniques have failed to determine unambiguously the nature of circulating microemboli. Recently, a new approach based on the analysis of radio frequency (RF) signal and using the nonlinear characteristics of gaseous bubbles to classify emboli was investigated. The main limitation of these studies was the requirement of two separate transducers for transmission and reception. This paper presents a multi-frequency transducer with two independent transmitting elements and a separate receiving part with a wide frequency band. The transmitting elements are positioned in a concentric design and cover a frequency band between 100 and 600 kHz. The receiving part consists of a polyvinylidene fluoride layer. The new transducer has been tested in vitro using gaseous emboli. It could correctly classify and size air emboli with diameters ranging from 10 microm to 105 microm.
将循环微栓子分类为气态或颗粒物质对于确定检测到的栓子信号的相关性至关重要。到目前为止，多普勒技术一直未能明确确定循环微栓子的性质。最近，研究了一种基于射频（RF）信号分析并利用气泡的非线性特性对栓子进行分类的新方法。这些研究的主要局限性在于需要两个单独的换能器进行发射和接收。本文介绍了一种具有两个独立发射元件和一个宽带单独接收部分的多频换能器。发射元件采用同心设计，覆盖100至600 kHz的频带。接收部分由聚偏二氟乙烯层组成。新换能器已在体外使用气态栓子进行了测试。它能够正确地对直径范围从10微米到105微米的空气栓子进行分类和测量大小。
