System Description and First Application of an FPGA-Based Simultaneous Multi-Frequency Electrical Impedance...

Area of Science:

• Biomedical Engineering
• Electrical Engineering
• Medical Imaging

Background:

• Electrical Impedance Tomography (EIT) is a non-invasive imaging technique.
• Multi-frequency EIT offers enhanced tissue characterization capabilities.
• Simultaneous multi-frequency measurements are crucial for advanced EIT applications.

Purpose of the Study:

• To present a novel prototype of a multi-frequency EIT system.
• To evaluate the system's performance for both time-difference and frequency-difference imaging.
• To demonstrate the first preliminary in-vivo frequency-difference EIT images.

Main Methods:

• A field-programmable gate array (FPGA) was utilized as the main controller.
• A composite waveform enabled simultaneous measurements across multiple frequencies.
• Real and imaginary impedance components were computed and transmitted via Ethernet.
• Time-difference and frequency-difference imaging algorithms were applied for reconstruction and visualization.

Main Results:

• The prototype successfully performed time-difference imaging across frequencies from 60 kHz to 960 kHz, aligning with simulation data.
• Preliminary frequency-difference images from in-vivo experiments were successfully generated, a novel achievement.
• The system computed both real and imaginary impedance components for each frequency.

Conclusions:

• The developed multi-frequency EIT system prototype demonstrates robust performance for time-difference imaging.
• The system enables preliminary frequency-difference imaging, including in-vivo applications.
• Further algorithmic development and normalization improvements are needed for optimal frequency-difference image reconstruction and interpretation.