title: Projection-resolved optical coherence tomographic angiography.
abstract: Shadowgraphic projection artifacts from superficial vasculature interfere with the visualization of deeper vascular networks in optical coherence tomography angiography (OCT-A). We developed a novel algorithm to remove this artifact by resolving the ambiguity between in situ and projected flow signals. The algorithm identifies voxels with in situ flow as those where intensity-normalized decorrelation values are higher than all shallower voxels in the same axial scan line. This "projection-resolved" (PR) algorithm effectively suppressed the projection artifact on both en face and cross-sectional angiograms and enhanced depth resolution of vascular networks. In the human macula, the enhanced angiograms show three distinct vascular plexuses in the inner retina and no vessels in the outer retina. We demonstrate that PR OCT-A cleanly removes flow projection from the normally avascular outer retinal slab while preserving the density and continuity of the intermediate and deep retinal capillary plexuses.
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA.
authors.forename: Miao
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Hwang
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA.
authors.forename: J Peter
authors.initials: JP
authors.lastname: Campbell
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA.
authors.forename: Steven T
authors.initials: ST
authors.lastname: Bailey
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Wilson
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA.
authors.forename: David
authors.initials: D
authors.lastname: Huang
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA.
authors.forename: Yali
authors.initials: Y
authors.lastname: Jia
keywords: (100.0100) Image processing; (100.2960) Image analysis; (110.4500) Optical coherence tomography; (170.4470) Ophthalmology