Vessel Density Correlation Between Differing Optical Coherence Tomography Angiography Devices is Variable and Dependent on Diabetic Retinopathy Severity

Abstract

Purpose : To compare retinal vascular quantitative metrics generated by 2 different optical coherence tomography angiography (OCTA) devices from eyes across the spectrum of diabetic retinopathy (DR) severity.

Methods : For this cross-sectional single visit study, eyes of participants with diabetes (DM) underwent 6x6 mm and 3x3 mm macular OCTA imaging using Optovue AngioVue and Zeiss AngioPlex as well as OCT (Spectralis) and ultrawide field (UWF, Optos 200°) imaging. Vascular density (VasD) of the superficial capillary plexus (SCP) was automatically quantified for Angiovue (software ver 2017.1.0.149) and AngioPlex images (software ver 10.0). DR severity was graded from UWF images. Central-involved DME (CIDME) was assessed from Spectralis OCT based on standard machine and gender-based thresholds.

Results : A total of 82 eyes of 41 subjects were imaged. Subjects were 36.7% female, 61.9% type 1 DM and had mean±SD age of 47±5 yrs and DM duration of 18±3 yrs. DR severity was: No DR 8.5% (N=7); nonproliferative DR (NPDR): mild 30.5% (25), moderate 20.7% (17), severe 12.2% (10); and proliferative DR 28.1% (23). AngioVue and AngioPlex VasD measurements for all eyes and eyes stratified by DR severity along with corresponding correlation coefficients are included in Table 1. Eyes with more severe DR had worse VasD correlations, but presence of CIDME did not reduce VasD correlation. When scans with quality <6 on either device were excluded, VasD correlations between the 2 devices did not improve. AngioVue images typically estimated greater VasD values than AngioPlex images. Mean±SD [range] differences between VasD measurements in all eyes were 6.3±4.6 [-3.8 to 18.4] for 3x3 mm and 6.0±5.8 [-3.8 to 25.0] for 6x6 mm scans.

Conclusions : Both AngioVue and AngioPlex show decreasing central retinal VasD in eyes with increasing DR severity. However, although software from both devices incorporate eye tracker, projection artifact removal and similar segmentation of the retinal layers, VasD measurements in eyes across the DR severity spectrum from the two devices are only moderately correlated. Furthermore, eyes with more severe DR are likely to have more variability in measurements across OCTA machines. Thus, direct comparisons of OCTA VasD measurements between machines and DR severity levels may not have good correlation and should account for these disparities.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.