Methods and Limits for Micro Scale Blood Vessel Flow Imaging in Scattering Media by Optical Feedback Interferometry:...

Area of Science:

• Biomedical optics
• Medical imaging
• Microcirculation research

Background:

• Skin vascular network architecture offers insights into human health.
• Optical methods are crucial for non-invasive vascular assessment.
• Understanding tissue scattering effects is key for optical imaging performance.

Purpose of the Study:

• To investigate the capabilities and limitations of optical feedback interferometry (OFI) for imaging skin vascularization.
• To analyze the impact of tissue scattering on OFI performance.
• To demonstrate OFI's potential for in vitro and in vivo blood flow imaging.

Main Methods:

• Design, fabrication, and characterization of skin-tissue simulating optical phantoms.
• Estimation of horizontal (2D) and vertical (depth penetration) sensing resolution of the OFI sensor.
• Experimental validation against theoretical models and in vivo human skin testing.

Main Results:

• OFI system successfully distinguished microfluidic channels (100 µm × 100 µm) spaced 10 µm apart in a 0.5 mm deep phantom with high scattering (up to 10.8 mm⁻¹).
• Experimental results showed strong agreement with theoretical models.
• Achieved the first 2D blood flow image of a human superficial vein using an OFI sensor.

Conclusions:

• OFI is a promising technique for high-resolution imaging of microvascular networks in biological tissues.
• The study validates OFI's performance in overcoming tissue scattering challenges.
• OFI demonstrates significant potential for non-invasive vascular diagnostics and health management.