A Polymer-Based CMUT Probe for Imaging the Spinal Cord in Rats

Area of Science:

• Biomedical Engineering
• Materials Science
• Medical Imaging

Background:

• Ultrasound imaging offers real-time visualization crucial for medical interventions.
• Small animal models in spinal cord injury research are limited by standard ultrasound system applicability.
• Capacitive Micromachined Ultrasonic Transducers (CMUTs) provide advantages like smaller size and design flexibility over piezoelectric transducers.

Purpose of the Study:

• To introduce the first polymer CMUT (polyCMUT) probe specifically designed for imaging rat spinal cords.
• To evaluate the performance and fabrication stability of a compact, 64-channel, 11 MHz polyCMUT probe.
• To assess the potential of polyCMUT technology for next-generation ultrasound systems in neuroscience research.

Main Methods:

• Developed a compact 11 MHz, 64-channel polyCMUT probe using a three-stage fabrication process.
• Integrated in-house manufactured polyCMUT arrays with electronics into a research imaging system.
• Conducted performance evaluations including electrical impedance, acoustic characterization, and in-vitro/ex-vivo imaging.

Main Results:

• Demonstrated a stable fabrication process with high yield and minimal variability (resonance frequency std. dev. < 1%).
• Successfully visualized rat spinal cord anatomical structures and real-time needle insertion.
• Identified limitations in distinguishing gray and white matter due to frequency and bandwidth constraints.

Conclusions:

• The developed polyCMUT probe shows significant potential for tailored ultrasound solutions in biomedical research.
• Further optimization of high-frequency performance is needed for in-vivo applications.
• This technology could provide valuable tools for spinal cord injury research and therapeutic interventions.