Abstract
Spectral-domain optical coherence tomography angiography (SD-OCTA) scans were used in an algorithm developed for swept-source optical coherence tomography angiography (SS-OCTA) scans to determine if SD-OCTA scans yielded similar results for the measurement of hyperreflective foci (HRF) in intermediate age-related macular degeneration (AMD).
Retrospective Study.
Forty eyes from 35 patients with intermediate AMD.
Patients underwent SD-OCTA and SS-OCTA imaging at the same visit using a 6x6 mm OCTA scan pattern. HRF were detected as hypotransmission defects (hypoTDs) on en face structural images generated from a custom slab positioned 64 to 400 μm beneath Bruch’s membrane and confirmed on corresponding B-scans by the presence of well circumscribed lesions within the neurosensory retina and/or along the retinal pigment epithelium (RPE) that are of equal or greater reflectivity than that of the RPE. Two independent graders evaluated the en face images and B-scans for the presence of these lesions. Outlines of HRF on en face images were generated using a published semiautomated algorithm developed for SS-OCTA scans and manually corrected by the graders when necessary. The total area measurements of the HRF within the 5 mm circle centered on the fovea were obtained from the algorithm using each imaging method.
Agreement of the square root (sqrt) of the HRF total areas obtained from SS-OCTA and SD-OCTA.
The sqrt total areas of the HRF from both imaging modalities were highly concordant, with Lin’s concordance correlation coefficient (rc) of 0.94 (95% CI: 0.86 to 0.97; p < 0.001). The mean sqrt of the total HRF area measurements identified using SS-OCTA and SD-OCTA imaging were 0.390 mm (SD: 0.170) and 0.393 mm (SD: 0.187), respectively with mean difference of -0.003 (95% CI: -0.021 to 0.015; p = 0.76).
SD-OCTA scans yielded results similar to SS-OCTA scans when the same semiautomated algorithm was used to measure HRF in the central 5 mm of the macula, suggesting that either a single 6x6 mm SD-OCTA or a SS-OCTA scan pattern can be used to determine the total macular HRF burden in eyes with AMD.