A Novel Intracranial Pressure Readout Circuit for Passive Wireless LC Sensor

Area of Science:

• Biomedical Engineering
• Medical Devices
• Wireless Sensing Technology

Background:

• Intracranial pressure (ICP) monitoring is crucial for diagnosing and managing neurological conditions.
• Existing ICP monitoring methods often involve invasive procedures or costly equipment.
• There is a need for accessible, wireless, and reliable ICP monitoring solutions.

Purpose of the Study:

• To develop and evaluate a low-cost, wireless system for intracranial pressure monitoring.
• To demonstrate the feasibility of using a passive implantable sensor with an external reader.
• To achieve accurate and real-time ICP measurements for clinical use.

Main Methods:

• Designed an implantable passive sensor with spiral coils to detect pressure-induced resonant frequency shifts.
• Developed a novel high-frequency circuit topology for an external reader to track impedance and phase changes.
• Utilized a wide frequency range (35 MHz-2.7 GHz) for wireless data acquisition.
• Validated the system's performance through prototype development and measurements.

Main Results:

• The wireless ICP monitoring system achieved a measurement distance greater than 2 cm.
• Demonstrated a sufficient sampling frequency exceeding 6 Hz for medical practice.
• Reported a high responsivity of 0.92 MHz/mmHg and a fine resolution of 0.028 mmHg.
• COMSOL simulations confirmed the system's safety regarding specific absorption rate.

Conclusions:

• The developed low-cost, wireless ICP monitoring system is a promising solution for medical applications.
• The novel circuit topology and passive sensor design enable reliable and accurate pressure measurements.
• Further improvements in antenna design, power radiation, ADC, and signal processing can enhance device performance.