Automated quantification of choriocapillaris anatomical features in ultrahigh-speed optical coherence tomography angiograms

In vivo visualization and quantification of choriocapillaris vascular anatomy is a fundamental step in understanding the relation between choriocapillaris degradation and atrophic retinopathies, including geographic atrophy. We describe a process utilizing ultrahigh-speed swept-source optical coherence tomography and a custom-designed “local min-max normalized masking” algorithm to extract in vivo anatomical metrics of the choriocapillaris. We used a swept-source optical coherence tomography system with a 1.6 MHz A-scan rate to image healthy retinas. With the postprocessing algorithm, we reduced noise, optimized visibility of vasculature, and skeletonized the vasculature within the images. These skeletonizations were in [Formula: see text] agreement with those made by skilled technicians and were, on average, completed in 18.6 s as compared to the 5.6 h technicians required. Anatomy within the processed images and skeletonizations was analyzed to identify average values ([Formula: see text]) of flow void radius ([Formula: see text]), flow void area [Formula: see text]), vessel radius [Formula: see text]), branch-point to branch-point vessel length [Formula: see text]), and branches per branch-point [Formula: see text]. To exemplify the uses of this tool a retina with geographic atrophy was imaged and processed to reveal statistically significant [Formula: see text] increases in flow void radii and decreases in vessel radii under atrophic lesions as compared to atrophy-free regions on the same retina. Our results demonstrate a new avenue for quantifying choriocapillaris anatomy and studying vasculature changes in atrophic retinopathies.