Abstract
Purpose :
Differentiating veins from arteries is clinically relevant to a wide range of retinal vascular diseases. We introduce a fast and reliable method to classify retinal vessels based on recognition of venous drainage origin from vortices within the deep capillary plexus (DCP).
Methods :
Nine 3x3 mm and 9 6x6 mm OCTA scans were acquired from healthy eyes of 14 subjects using PLEX Elite 9000 (Zeiss Meditec Inc, Dublin, CA). The default en face slabs (color retina depth encoded, greyscale full-thickness retina, superficial plexus, and DCP with projection removal) were exported and aligned. A total of 147 vessels on 3x3 mm images and 193 vessels on 6x6 mm images were labeled. Eight ophthalmologists without OCTA experience classified all labeled vessels as arteries or veins in 3 stages. Stage 1: Untrained classification based on graders’ own assessment was performed. Stage 2: Graders were taught that a capillary-free zone was an anatomic feature of arteries. Stage 3: Graders were trained that veins originate from vortices within the DCP (characterized as green convergence of capillaries on color depth encoded slab) and arteries and veins alternate as each vein drains capillary beds perfused by adjacent arteries (Fig. 1). Three 3x3 mm and 3 6x6 mm scans were used in each stage. Grading performance and time were evaluated and compared.
Results :
Mean accuracy and time spent on each vessel in each stage and statistics results including the correlations between accuracy and time, accuracy and year of practicing, and comparisons of accuracy between stages and scanning patterns are shown in Fig. 2.
Conclusions :
We demonstrated a novel OCTA-based method for classifying retinal vessels using the vortices in the DCP as an anatomic biomarker for identifying venous origin, which is reliable and superior to the capillary-free zone strategy. Our study also supports a serial arrangement pattern that the venous outflow predominantly drainage through the DCP.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.