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Steven T Bailey, Yali Jia, Christina J Flaxel, Thomas S Hwang, Martin F Kraus, David Huang; Detection of occult choroidal neovascularization in age-related macular degeneration with optical coherence tomography angiography. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):3329.
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© ARVO (1962-2015); The Authors (2016-present)
To visualize occult choroidal neovascularization (CNV) in age-related macular degeneration using OCT angiography.
15 eyes from 13 study participants with active occult CNV, as defined by fluorescein angiography (FA), were scanned with either a prototype (100 kHz A-scan repetition rate) swept-source OCT acquiring 3x3 mm scans or a commercially available high-speed spectral OCT (70 kHz, RTVue XR, Optovue, Inc.) acquiring both 3X3 and 6X6 mm scans. Flow was detected with the split-spectrum amplitude decorrelation angiography (SSADA) algorithm and motion artifact was removed by 3D orthogonal registration and merging of 2 scans. The volumetric angiogram was segmented into inner retinal, outer retinal and choroidal layers to construct separate en face angiograms. CNV was identified as vessels above Bruch's Membrane in the outer retinal layer. CNV area was assessed by summing pixels with detectable flow in the en face outer retinal angiogram. Composite color-coded angiograms allowed for en face visualization of multiple vascular beds as well as representation of both flow and structure on cross sections.
In 9 eyes with fibrovascular pigment epithelial detachment (PED), large CNV vessels with smaller vascular fronds were seen with OCT angiography; while FA revealed only large diffuse areas of staining and leakage (Fig 1). In 6 eyes with stippled hyperfluorescence from an undetermined source with FA, OCT angiography demonstrated a clearly defined vascular network in the outer retina (Fig. 2). CNV area could be assessed in all cases. Cross-sectional OCT angiograms demonstrated type 1 CNV in all cases.
OCT angiography with SSADA improved visualization of occult CNV compared to FA. All cases were type 1 CNV. CNV were ill-defined with FA due to fluorescein leakage and from blockage from retinal pigment epithelial cells. CNV areas were quantified with OCT angiography, which may be useful barometer in assessing response to treatment.
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