Three-dimensional visualization of choroidal vessels by using standard and ultra-high resolution scattering optical coherence angiography

Scattering optical coherence angiography (S-OCA) is a noninvasive imaging method that is based on the high-speed standard 800nm band spectral-domain optical coherence tomography (SD-OCT) and the ultra-high-resolution SD-OCT which has the axial resolution of 6.1 mum and 2.9 mum in tissue, respectively. In this paper, we have demonstrated the use of this method for in vivo human retinal imaging. A three-dimensional view of the choroidal vasculature was obtained by segmenting the choroidal vessels; this was done using intensity threshold based binarization at each depth plane relative to the retinal pigment epithelium. A vascular projection image was obtained by integrating the segmented choroidal vasculature. In order to assess the feasibility of the proposed method, we compared these images with those obtained using existing invasive methods such as fluorescein angiography and indocyanine green angiography. Clinically worthful images are obtained from the application of S-OCA to the agerelated macular degeneration and polypoidal choroidal vasculopathy.