Wearable Electrical-impedance-tomography Armband for Noninvasive and Continuous Bone Monitoring

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Wearable Technology

Background:

• Conventional medical imaging like digital radiography (DR) and computed tomography (CT) pose limitations for continuous fracture healing monitoring due to cumulative radiation exposure.
• There is a need for noninvasive, long-term monitoring solutions for bone health, particularly during the healing process.

Purpose of the Study:

• To develop and validate a wearable electrical impedance tomography (EIT) armband for noninvasive, continuous monitoring of arm bones.
• To assess the EIT armband's capability in detecting changes in bone conductivity indicative of fracture healing.

Main Methods:

• A 16-electrode armband system utilizing EIT was designed for skin surface current stimulation and voltage detection.
• Finite-element modeling was employed to optimize armband configurations, including electrode number and stimulation/acquisition patterns.
• Phantom experiments with 3D-printed bones and ex vivo studies on porcine bones were conducted to validate the system's accuracy and monitoring capabilities.

Main Results:

• The EIT armband successfully reconstructed cross-sectional images of forearm bones (ulna and radius) with acceptable accuracy.
• A 2.5 mm fracture notch in the radius was detected as an increase in conductivity.
• Ex vivo studies demonstrated the EIT system's ability to track conductivity variations during simulated fracture healing processes in porcine bones.

Conclusions:

• The developed wearable EIT armband offers a noninvasive and continuous method for monitoring arm bones, with significant potential for fracture healing assessment.
• The technology shows promise for long-term bone monitoring and could be adapted for other bones like the fibula and tibia.