Li J H, Joppek C, Faust U
Institut für Biomedizinishce Technik, Universität Stuttgart, Germany.
Physiol Meas. 1996 Nov;17 Suppl 4A:A25-32. doi: 10.1088/0967-3334/17/4a/005.
A wide-band high-speed data acquisition system for electrical impedance tomography (EIT) is described. 32 active electrodes are used in the system, half of them as receive electrodes and the other half as drive electrodes. A buffer is mounted on the back of each receive electrode and a current source on each drive electrode. A multielectrode system with active electrodes was built to make it convenient to attach all the electrodes on the human thorax. The system is suitable for both dynamic imaging and multifrequency electrical impedance tomography (MFEIT). Its operating frequency can be chosen between 24 kHz and 400 kHz. Current is injected sequentially into 16 adjacent current electrode pairs and the 16 voltages between adjacent receive electrodes are measured for each current injection. ECG is collected to determine the relationship between the reconstructed images and cardiac activity. The collection of one frame of data is completed within 25 ms. The system has been successfully used for imaging the variation of conductivity distribution of the human thorax. The beat-by-beat cardiac-related change of conductivity distribution has been imaged by our system. The quasi-periodic variation of the impedance distribution can be seen from the image sequence with breath-holding.
介绍了一种用于电阻抗断层成像（EIT）的宽带高速数据采集系统。该系统使用32个有源电极，其中一半用作接收电极，另一半用作驱动电极。每个接收电极背面安装一个缓冲器，每个驱动电极上安装一个电流源。构建了一个带有有源电极的多电极系统，以便于将所有电极附着在人体胸部。该系统适用于动态成像和多频电阻抗断层成像（MFEIT）。其工作频率可在24 kHz至400 kHz之间选择。电流依次注入16对相邻的电流电极对，并在每次电流注入时测量相邻接收电极之间的16个电压。采集心电图以确定重建图像与心脏活动之间的关系。一帧数据的采集在25毫秒内完成。该系统已成功用于对人体胸部电导率分布的变化进行成像。我们的系统已对与心脏逐搏相关的电导率分布变化进行了成像。从屏气时的图像序列中可以看到阻抗分布的准周期性变化。
