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Peter L Nesper, Amani A Fawzi; Distinguishing Choroidal Neovascularization from Residual Choroidal Vessels in Geographic Atrophy on OCT Angiography. Invest. Ophthalmol. Vis. Sci. 2017;58(8):376.
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© ARVO (1962-2015); The Authors (2016-present)
Patients undergoing long-term anti-vascular endothelial growth factor therapy for choroidal neovascularization (CNV) have been shown to develop atrophic changes, clinically indistinguishable from de novo geographic atrophy (GA). Our goal was to investigate lesions with significant overlap between GA and CNV in eyes with age-related macular degeneration using optical coherence tomography angiography (OCTA).
Cross-sectional study of 32 eyes of 26 patients (mean age, 83.5 ± 6.33 years) who had evidence of atrophy in the setting of treated CNV, and 8 eyes of 7 treatment-naïve patients (mean age, 81.0 ± 7.02 years) with de novo GA. En face OCT slabs were used to highlight areas of retinal pigment epithelium (RPE) loss, and then combined with OCTA. Cross-sectional OCT and post-processed en face OCTA were analyzed to identify the presence and location of CNV and GA. Our main outcome measure was the utility of OCTA post-processing in identifying CNV and distinguish them from normal, residual choroidal vessels in GA.
Large, normal choroidal vessels were displaced anteriorly in areas of GA, which was confirmed on cross-sectional OCTA. These vessels were visible in the choriocapillaris slab on en face OCTA in all 40 eyes (100%) and in the outer retinal slab (simulating CNV) in 30 of 40 eyes (75.0%). Post-processing successfully highlighted GA. Cross-sectional OCTA was needed to confirm the presence of CNV, as flow signal above Bruch’s membrane, due to similar en face appearances of CNV and normal choroidal vessels.
Post-processing facilitated the interpretation of en face OCTA by adding structural information that highlighted the RPE loss and GA. Normal choroidal vessels were displaced anteriorly in areas of GA, which may lead to confusion in diagnosis. Clinicians need to carefully interpret en face OCTA in these eyes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
Choroidal Neovascularization (CNV) in the Area of Geographic Atrophy (GA). OCTA of choriocapillaris (Left) & outer retina (Middle) show large caliber vessels. (Right) Pseudo-colored OCTA of choriocapillaris. Areas of GA are pseudo-colored on a spectrum from blue to yellow, and areas with intact retinal pigment epithelium are pseudo-colored magenta. Blood vessels appearing in the outer retina are pseudo-colored green. Pseudo-coloring clearly delineates the extent of the GA and distinguishes normal choroidal vessels (orange) from the CNV (green).
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