title: Efficient method to suppress artifacts caused by tissue hyper-reflections in optical microangiography of retina in vivo.
abstract: Optical microangiography (OMAG) is an optical coherence tomography (OCT)-based imaging technique that is capable of achieving the angiographic imaging of biological tissues in vivo with a high imaging resolution and no need for dye injection. OMAG has a potential to become a clinical tool for the diagnosis and treatment monitoring of various retinopathies. In principle, OMAG extracts blood flow information based on a direct differentiation of complex or intensity OCT signals between repeated B-scans acquired at the same cross section, which is sensitive to blood cell movement. In practice, this method is prone to artifacts due to tissue hyper-reflection, commonly seen in retinal diseases such as diabetic retinopathy. In this paper, we propose a novel method to suppress the artifacts induced by hyper-reflection. We propose to scale OMAG flow signals by a weighting factor that is motion-sensitive but hyper-reflection insensitive. We show that this simple weighting approach is effective in suppressing the artifacts due to tissue hyper-reflections while still maintaining the detected capillary networks with high fidelity, especially in deeper retina. The effectiveness of the proposed technique is demonstrated by a phantom study and case studies on patients' eyes with hyper-reflective foci. Finally we discuss potential applications of this technique.
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA.
authors.forename: Qinqin
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Bioengineering, University of Washington, 3720 15th NE, Seattle, WA 98195, USA.
authors.forename: Ruikang K
authors.initials: RK
authors.lastname: Wang
keywords: (170.1470) Blood or tissue constituent monitoring; (170.2655) Functional monitoring and imaging; (170.4500) Optical coherence tomography