Single-scan adaptive optics-enabled quantitative optical coherence tomography angiography for absolute...

Area of Science:

• Ophthalmology
• Biomedical Imaging
• Microcirculation Research

Background:

• Accurate retinal blood flow measurement is vital for understanding metabolic function and diseases like diabetic retinopathy.
• Current imaging methods (OCTA, Doppler OCT) lack direct, absolute blood flow quantification, especially at the capillary level.
• Advances in adaptive optics (AO) and swept-source lasers allow high-speed imaging of individual red blood cells (RBCs).

Purpose of the Study:

• To develop and validate a quantitative AO-OCTA approach for 3D blood flow mapping in the human retina.
• To enable noninvasive, high-resolution measurement of microvascular flow dynamics.
• To provide a tool for improved diagnosis and research of retinal vascular diseases.

Main Methods:

• Integrated OCTA-derived vessel morphology with a 3D Radon transform of RBC streaks.
• Utilized raw spatio-temporal OCT data to measure individual RBC velocity.
• Developed a post-processing pipeline for single-cell velocity, vessel diameter, and flow rate determination from a single scan.

Main Results:

• Demonstrated depth-resolved flow rate measurements in retinal vessels ranging from 5 to 120 μm in diameter.
• Quantified velocities from 0.5 to 54 mm/s, capturing diverse retinal flow dynamics.
• Successfully mapped 3D blood flow with high resolution and accuracy.

Conclusions:

• The presented quantitative AO-OCTA method offers robust, noninvasive microvascular flow quantification.
• This technique significantly advances the capability for high-resolution blood flow imaging in the retina.
• Potential applications include biomedical research and clinical diagnostics for retinal vascular conditions.