Cuffing-based photoacoustic flowmetry in humans in the optical diffusive regime

Area of Science:

• Biomedical Optics
• Medical Imaging
• Hemodynamics

Background:

• Accurate measurement of blood flow speed in humans is crucial for diagnosing and monitoring various medical conditions.
• Photoacoustic tomography (PAT) faces challenges in quantifying blood flow in the optical diffusive regime.
• Existing methods for blood flow measurement can be invasive or lack portability for bedside applications.

Purpose of the Study:

• To develop and validate a non-invasive, cuffing-based method for quantifying blood flow speed in humans using a handheld photoacoustic probe.
• To assess the performance of the proposed method in both phantom and human subjects.
• To explore the potential clinical applications of this portable blood flow measurement technique.

Main Methods:

• A cuffing technique was employed, involving controlled compression and release of a blood vessel, to induce measurable changes in downstream blood flow.
• A handheld photoacoustic probe was utilized to detect and quantify these changes, enabling blood flow speed calculation.
• Experiments were conducted using phantoms to establish the measurable range of flow speeds and in human subjects to validate the method on different vasculature.

Main Results:

• The cuffing-based photoacoustic method successfully quantified blood flow speed in human subjects.
• Phantom experiments demonstrated a measurable flow speed range from 0.035 mm/s to 42 mm/s.
• Blood flow speeds were accurately measured in a radial artery (forearm), a radial artery (finger), and a radial vein (forearm).

Conclusions:

• The proposed cuffing-based photoacoustic method provides a reliable approach for measuring blood flow speed in humans.
• The handheld nature of the probe enhances portability and potential for widespread clinical use.
• This technique holds promise for non-invasive, real-time monitoring of blood flow at the patient's bedside.