OCT Angiography (OCTA) of Neovascularization in Macular Telangiectasia Type 2

Abstract

Purpose : To evaluate neovascularization in proliferative macular telangiectasia Type 2 (MacTel2) using swept-source (SS) and spectral-domain (SD) optical coherence tomography (OCT) angiography.

Methods : Patients with MacTel2 were enrolled in a prospective, observational study and evaluated using a prototype 1050 nm SS-OCT system at a 100 kHz A-scan rate and an 840nm SD-OCT system at a 68 kHz A-scan rate. On both systems, angiographic images were obtained by using a complex algorithm that incorporates changes in both intensity and phase information from repeated B-scans. 3X3 mm raster scans were obtained from both systems, with 4 repeated B-scans at each location. In the SS-OCT system, 300 A-scans were contained in each B-scan and a total of 300 B-scans positions were generated over a 3mm distance. The SD-OCT used for this study was the Zeiss AngioPlex OCT angiography instrument in which 245 A-scans were contained in each B-scan and 245 B-scan positions were generated over the 3 mm distance. The algorithms for both SS-OCT and SD-OCT segmented the retina into five layers including the inner retinal layer, middle retinal layer, outer retinal layer, choriocapillaris, and choroid. Custom segmentations were also performed to optimize visualization of the neovascularization. Fluorescein angiography (FA) was performed on all patients and two of the patients underwent indocyanine green angiography (ICGA).

Results : OCT angiography imaging was performed on 42 patients (84 eyes) with MacTel2 and of those, 6 patients (10 eyes) were affected with neovascularization. SS-OCT and SD-OCT imaging identified neovascularization better than FA and were comparable to images obtained using ICGA. In all 6 cases, custom segmentation of the neovascularization identified the presence of choroidal vessels anastomosing with the retinal vasculature in the subretinal compartment.

Conclusions : Both SS-OCT and SD-OCT angiography provided rapid and detailed depth-resolved information about neovascularization in MacTel2 patients. These results suggest that OCT angiography is superior to FA in documenting the microvascular changes, extent of neovascularization, and its communication with the choroidal circulation.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.