Optical coherence tomography angiography of type 3 macular neovascularization, a clinicopathologic correlation

Abstract

Purpose : Correlation of in vivo optical coherence tomography angiography (OCTA) of type 3 macular neovascularization (t3 MNV) secondary to AMD with corresponding ex vivo histology.
Exploring the overall value of clinical OCTA for disease observation, diagnosis, and staging by validating OCTA in the analysis of type 3 macular neovascularization secondary to AMD.

Methods : A white woman receiving anti-VEGF (OD, n=37; OS, n=6; last visits 3 and 2 months, respectively, before death at age 97 years) was monitored by optical coherence tomography (OCT) and angiography (OCT and dye-based). Eyes were recovered 4:05 hours after death, processed for macula-wide epoxy-resin histology, and scanned under an oil objective for high-resolution microscopy. Infrared reflectance and eye-tracked spectral-domain OCT(A) clinical imaging were correlated with ex vivo and high-resolution histologic images. Projection artifact removal based on three-dimensional vessel-shape estimation (VSE-PAR) and a Gaussian blur filter for preservation of neovascular flow signal was used.

Results : Clinical OCT(A) imaging showed several neovascular lesions within the central macula of both eyes. Two index lesions of different phenotypes in the right eye displayed a drusenoid pigment epithelium detachment (PED), characteristic of t3 MNV. Projection artifact removal based on VSE-PAR and a Gaussian blur filter demonstrated robust preservation of neovascular flow signal. OCTA decorrelation signal in lesion # 1 corresponded in histology to a vertically oriented collagen-ensheathed vascular complex originating from the intermediate capillary plexus. Lesion # 2 corresponded to a horizontally oriented vascular loop originating from the deep capillary plexus. Both lesions contacted basal laminar deposits that remained after the retinal pigment epithelium (RPE) disappeared due to death in situ or anterior migration. The sub-RPE-basal laminar space (between RPE-basal lamina and inner collagenous layer of Bruch’s membrane) underlying these vascular abnormalities contained calcific nodules and glial processes. No connection between the choriocapillaris and this space was observed for either lesion.

Conclusions : OCTA decorrelation signal of type 3 neovascularization corresponded to two intraretinal neo-vessel phenotypes on histology.
VSE-PAR and Gaussian blur filter demonstrated their value for further use in OCTA decorrelation signal processing.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.