Validation of Compensation Algorithm in Healthy Volunteers Using Spectral Domain Optical Coherence Tomography Angiography.

Abstract

Purpose: To generate and validate a spectral domain optical coherence tomography angiography (SD-OCTA) device-specific algorithm to compensate for signal attenuation in choriocapillaris (CC) en face OCTA slabs.

Methods: Healthy subjects were imaged on SD-OCTA with a 6 × 6 mm pattern at the Doheny-UCLA Eye Centers. The CC slabs were segmented at the level of the Bruch's membrane using a 16-μm thick slab with the inner boundary located 4 μm below the Bruch's membrane. The CC slabs were exported and normalized. The percentage of CC flow deficits (CC FD %) was computed on binarized slabs before and after the application of an SD-OCTA specific compensation algorithm. On the same cohort, we also tested the compensation algorithm previously developed for SS-OCTA CC slabs.

Results: Twenty-eight eyes from 28 subjects were included in the analysis. The mean (SD) CC FD % was 13.15 (3.91) for the normalized and compensated (SD-OCTA specific) images and 13.73 (4.20) for the normalized and uncompensated images (p = 0.1). The compensated and uncompensated CC FD were strongly correlated (p < 0.001). Bland-Altman plots demonstrated good agreement between the compensated and uncompensated CC slabs for the quantification of CC FD. When applying the SS-OCTA compensation algorithm on the SD-OCTA CC slabs, there was a statistically significant difference between CC FD% measured on the compensated and uncompensated CC slabs (p < 0.0001).

Conclusions: An SD-OCTA specific compensation algorithm can be applied which does not cause the loss of artifactual FD in healthy eyes, with similar CC FD% values in compensated and uncompensated images.