Non-Invasive Blood Perfusion Measurements Using a Combined Temperature and Heat Flux Surface Probe

Area of Science:

• Biomedical Engineering
• Medical Devices
• Physiology

Background:

• Accurate blood perfusion measurement is crucial for diagnosing and monitoring various medical conditions.
• Existing methods for assessing blood perfusion can be invasive or lack sensitivity.
• Developing non-invasive techniques is essential for improving patient care and research.

Purpose of the Study:

• To develop and validate a novel non-invasive system for measuring blood perfusion in biological tissues.
• To assess the repeatability and sensitivity of the developed perfusion measurement probes.
• To evaluate the system's performance in both a controlled phantom tissue model and an animal model.

Main Methods:

• Utilized a small sensor with a laminated flat thermocouple to measure heat transfer and temperature response to thermal stimuli.
• Developed a mathematical model to estimate blood perfusion and thermal contact resistance by comparing heat flux data.
• Tested probe repeatability and sensitivity using a phantom tissue test stand with controlled water flow and in exposed rat liver models with induced blood flow changes.

Main Results:

• The phantom tissue tests demonstrated the probes' ability to detect small changes in perfusion as low as 0.005 ml/ml/s.
• The probes qualitatively tracked changes in rat liver perfusion when blood flow was occluded via the portal vein.
• The system showed good repeatability and sensitivity in both tested models.

Conclusions:

• The developed non-invasive blood perfusion measurement system shows significant potential for accurate and sensitive tissue perfusion assessment.
• The thermal sensing probes offer a promising alternative to invasive methods for monitoring perfusion.
• Further research and clinical validation are warranted to explore the full clinical utility of this technology.