Does optical microangiography provide accurate imaging of capillary vessels?: validation using multiphoton microscopy

Area of Science:

• Biomedical Optics
• In Vivo Imaging
• Vascular Biology

Background:

• Optical microangiography (OMAG) is widely used for in vivo 3D tissue vasculature imaging.
• Concerns exist regarding OMAG's resolution (∼10 μm) for imaging capillaries (∼6 μm) and quantifying vascular density.
• Multiphoton microscopy (MPM) offers high resolution (∼1 μm) and depth-resolved imaging of biological structures.

Purpose of the Study:

• To compare the capabilities of OMAG and MPM in imaging in vivo mouse brain vasculature.
• To validate OMAG's ability to visualize and quantify capillary networks.
• To assess OMAG's suitability for microvasculature studies.

Main Methods:

• Acquisition of in vivo mouse brain vascular images using both OMAG and MPM systems.
• Comparison of image resolution and visualization of capillary vessels between the two techniques.
• Assessment of OMAG's capacity for vascular density quantification.

Main Results:

• OMAG accurately visualizes blood vessels, including capillaries, within the penetration depth of MPM.
• While OMAG may not resolve extremely close capillaries, it visualizes most due to interstitial spaces.
• OMAG demonstrates potential for meaningful quantification of vascular density.

Conclusions:

• OMAG is capable of visualizing capillaries in vivo, addressing previous resolution concerns.
• The study validates OMAG as a reliable tool for microvasculature imaging and quantification.
• These findings support the expanded application of OMAG in microcirculation research.