Abstract
Purpose:
Optical coherence tomography angiography (OCTA) to visualize chorioretinal vasculature can be performed using both 840 nm wavelength spectral domain (SD) as well as 1060 nm swept source (SS) systems. This cross sectional, observational case series compares and contrasts the imaging capabilities of SS-OCTA to SD-OCTA in a variety of cases.
Methods:
9 subjects underwent sequential same-day SD-OCTA and SS-OCTA at the New England Eye Center between 8/2014 and 11/2014. These subjects included 1 normal control and 8 with a variety of chorioretinal diseases including wet age-related macular degeneration, central serous chorioretinopathy, central retinal vein occlusion, diabetic retinopathy, birdshot chorioretinopathy, Best’s disease and retinitis pigmentosa. All subjects were imaged on a prototype SS-OCTA system featuring an imaging speed of 400 kHz, with an axial resolution of 7-10 um and 5 repeated B-scans per position. All subjects were also imaged with the AngioVue OCTA system on the commercially available Avanti SD-OCT (Optovue, Inc, Fremont, CA) operating at 70 kHz with an axial resolution of 5um using 2 repeated B-scans. An investigational OCTA software program was used to evaluate the images. Images were compared qualitatively. When available, OCTA was also compared with corresponding fluorescein angiography (FA).
Results:
High quality images were obtained on both systems in all subjects. All data sets were segmented and vascular layers in the retina and choroid were identified. Pathologic features of disease were identified in images from both systems. These pathologic features, including choroidal neovascular membranes (Figure 1), retinal microaneurysms and vessel dropout were correlated between scanning systems and with FA. Better quality images of the choroidal vasculature were obtained with the SS-OCTA especially in patients with ocular opacities including subretinal lipofuscin deposits. No retinal vascular pathology could not be identified on both systems.
Conclusions:
Both SS-OCTA and SD-OCTA have a role in evaluating chorioretinal vasculature and demonstrate consistent findings.