Multi-center repeatability of macular capillary perfusion density using optical coherence tomography angiography

Abstract

Purpose : To determine the test-retest repeatability in quantifying macular capillary perfusion density (CPD) using optical coherence tomography angiography (OCTA) in a multi-center setting.

Methods : OCTA data was obtained in self-reported healthy subjects from Bascom Palmer Eye Institute at the University of Miami (UM, N = 18) and the University of Pennsylvania (UPenn, N = 25). OCTA was repeated at an interval of one week for assessment of repeatability (precision) in the same subjects. Analysis of OCTA-derived capillary perfusion density (OCTA-CPD) focused on the macula. Image processing procedures and fractal analysis developed in our lab were used to process OCTA data. Fractal analysis was performed on the skeletonized vascular images to yield vessel densities by box-counting in an annulus to fractal dimension (Dbox) yielding OCTA-CPD. Large vessel and microvessel network densities (D_box) as CPD of annuli (0.5-2.5 mm in diameter from 3 mm scans and 0.5 – 5.0 mm from 6 mm scans) in the total retinal vascular network (RVN), superficial (SVP), and deeper vascular plexuses (DVP) were analyzed. Repeatability was assessed by 3 measures: standard deviation (SD), coefficient of variation (CV) of repeated measures, and intraclass correlation coefficient (ICC).

Results : SD, CV, and ICC are listed in table 1. Both sites (UPENN and UM) had similar results. The CV% was about 0.5% which presents high measurement repeatability. However, the ICC was lower than expected, possibly due to the narrow CPD ranges in this healthy cohort. The ICC for the 3 mm scans was higher than that for the 6 mm scans from both sites.

Conclusions : While data collection and analysis are ongoing, our preliminary data showed high repeatability in both research sites, according to the CV. Scans with the 3 mm setting appear to be more repeatable.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.