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Thomas Callan, Luis De Sisternes, Warren Lewis, Sophie Bonnin, Torcato Santos, Jose G Cunha-Vaz, Sophie Kubach; Comparison of vessel density and vessel perfusion measurements in SD-OCT and SS-OCT devices. Invest. Ophthalmol. Vis. Sci. 2022;63(7):2949 – F0102.
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© ARVO (1962-2015); The Authors (2016-present)
Optical coherence tomography angiography (OCTA) expands the ability to detect and monitor retinal vascular changes. Both vessel density (VD) and perfusion density (PD) are parameters that can be quantified from OCTA en face images. This study looks at these parameters and compares the results generated by both a spectral domain (SD) and a swept-source (SS) OCT system.
Subjects were scanned multiple times with the PLEX® Elite 9000 (ZEISS, Dublin, CA) SS-OCT and the CIRRUS™ HD-OCT 5000 (ZEISS, Dublin, CA). Three groups of eyes (41 total) were evaluated: 30 diseased eyes of 15 patients with varying diabetic retinopathy severity were imaged on PLEX Elite with the Angio 6x6 mm at 100 kHz scan and on CIRRUS using the 3x3 mm Angiography scan. One cohort of 6 healthy eyes and another cohort of 5 diseased eyes were imaged 3 times on both PLEX Elite and 3 times on CIRRUS. These results were pooled. VD is the total length of perfused vasculature per unit area in a region. PD is defined as the total area of perfused vasculature per unit area in a region. The inner ETDRS subfields (1-5) these scans have in common were used. The intra-instrument coefficient of variation (COV), defined as the ratio of the standard deviation to the mean, was calculated for each device. In addition, the relative mean difference in measurement between the 2 devices were determined.
Data analysis of these repeated scans showed a similar intra-device coefficient of variation between PLEX Elite and CIRRUS. The COV for vessel density was 3.4% for Plex and 4.7% for CIRRUS. The COV for perfusion density was 3.8% for PLEX Elite and 5.4% for CIRRUS. The relative mean difference in vessel density between CIRRUS and PLEX Elite was 0.02%. The relative mean difference in perfusion density between CIRRUS and PLEX Elite was 1.3%. Both values are smaller than the combined intra-device COVs for the two quantities.
The relative differences in measurement between PLEX Elite and CIRRUS for vessel density and perfusion density are much smaller that the intra-device variability. This indicates the measurement between the two instruments can be considered substantially similar when considering these OCT vascular parameters.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.
Figure 1a, b: Plots showing similar values between Plex Elite and CIRRUS for a) VD and b) PD. Each point indicates a measured value from one of the ETDRS subfields (1-5).
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