Fast pulsatile blood flow measurement in deep tissue through a multimode detection fiber

Area of Science:

• Biomedical Optics
• Physiological Monitoring
• Medical Instrumentation

Background:

• Noninvasive measurement of deep tissue pulsatile blood flow is crucial for assessing cardiovascular health.
• Blood flow waveform analysis correlates with blood pressure and vessel elasticity, aiding in disease detection (e.g., stroke, ischemia).
• Existing methods lack portability and cost-effectiveness, creating a clinical demand for improved devices.

Purpose of the Study:

• To develop and validate a diffuse-optics-based method, diffuse speckle pulsatile flowmetry (DSPF), for fast, noninvasive deep tissue blood flow measurement.
• To demonstrate the system's performance using phantom experiments and in vivo studies.
• To enhance the measurement rate and usability of deep tissue blood flow monitoring.

Main Methods:

• A diffuse speckle pulsatile flowmetry (DSPF) system was developed using a multimode (MM) detection fiber (200 μm core size).
• A background intensity correction algorithm was implemented for speckle contrast calculation.
• System performance was validated through flow phantom experiments and an in vivo cuff-induced occlusion study.

Main Results:

• The DSPF system achieved a fast measurement rate of approximately 300 Hz for deep tissue blood flow.
• The use of an MM detection fiber enabled deep tissue blood flow measurement comparable to conventional methods.
• The system demonstrated its capability in detecting pulsatile blood flow changes during an in vivo occlusion experiment.

Conclusions:

• A multimode detection fiber facilitates fast (∼300 Hz) pulsatile blood flow measurement using the DSPF method.
• The developed DSPF system is cost-effective and features a flexible, fiber-based probe, significantly enhancing its clinical usability.
• This technology offers a promising solution for portable and accessible noninvasive blood flow monitoring.