Automated Quantification of Capillary Nonperfusion Using Optical Coherence Tomography Angiography in Diabetic Retinopathy

Abstract:The purpose of this work is to investigate the benefits of adaptive optics (AO) technology for optical coherence tomography angiography (OCTA). OCTA has shown great potential in non-invasively enhancing the contrast of vessels and small capillaries. Especially the capability of the technique to visualize capillaries with a lateral extension that is below the transverse resolution of the system opens unique opportunities in diagnosing retinal vascular diseases. However, there are some limitations of this technology such as shadowing and projection artifacts caused by overlying vasculature or the inability to determine the true extension of a vessel. Thus, the evaluation of the vascular structure and density based on OCTA alone can be misleading. In this paper we compare the performance of AO-OCT, AO-OCTA and OCTA for imaging retinal vasculature. The improved transverse resolution and the reduced depth of focus of AO-OCT and AO-OCTA greatly reduce shadowing artifacts allowing for a better differentiation and segmentation of different vasculature layers of the inner retina. The comparison is done on images recorded in healthy volunteers and in diabetic patients with distinct pathologies of the retinal microvasculature.

Section: Discussionmentioning

confidence: 99%

“…Several groups reported on early and late changes in the retinal micro-vasculature using OCTA [41][42][43][44][45]. Figure 11(A) shows an overview OCTA image recorded with a commercial instrument (AngioVue, Optovue; The AngioPlex OCT was not available for the patient measurements).…”

Section: Patients With Diabetic Retinopathymentioning

confidence: 99%

Visualization of micro-capillaries using optical coherence tomography angiography with and without adaptive optics

Salas

Augustin

Ginner

et al. 2016

“…It uses erythrocyte movement against the static feature as intrinsic contrast to provide perfusion information of the retinal vessel network without fluorescent dye injections. It is particularly useful in evaluation of age-related macular degeneration (AMD) and DR by revealing both neovascularization as well as areas of vascular non-perfusion [36,37]. Several current available OCT angiography systems (e.g.…”

Section: Discussionmentioning

confidence: 99%

Computational fluid dynamics assisted characterization of parafoveal hemodynamics in normal and diabetic eyes using adaptive optics scanning laser ophthalmoscopy

Bernabéu¹,

Lammer²,

Cai³

et al. 2016

Diabetic retinopathy (DR) is the leading cause of visual loss in working-age adults worldwide. Previous studies have found hemodynamic changes in the diabetic eyes, which precede clinically evident pathological alterations of the retinal microvasculature. There is a pressing need for new methods to allow greater understanding of these early hemodynamic changes that occur in DR. In this study, we propose a noninvasive method for the assessment of hemodynamics around the fovea (a region of the eye of paramount importance for vision). The proposed methodology combines adaptive optics scanning laser ophthalmoscopy and computational fluid dynamics modeling. We compare results obtained with this technique with in vivo measurements of blood flow based on blood cell aggregation tracking. Our results suggest that parafoveal hemodynamics, such as capillary velocity, wall shear stress, and capillary perfusion pressure can be noninvasively and reliably characterized with this method in both healthy and diabetic retinopathy patients.

“…It enables a high sensitivity, high speed and non-invasive way to acquire the cross-sectional reflectivity profile of a sample [5,6]. Besides information on the layer structure, optical coherence tomography angiography (OCTA) algorithms [7,8] allow depth-resolved visualization of the retinal and choroidal blood circulation [9][10][11] and identification of abnormal vascular and blood flow changes [12] in ocular diseases such as glaucoma [13][14][15], age-related macular degeneration [16,17], and diabetic retinopathy [18,19]. Additionally, OCT has become a powerful research tool for 3D imaging of complex myocardial activities in early-stage embryonic hearts with high spatial and temporal resolution.…”

Section: Introductionmentioning

confidence: 99%

Angiographic and structural imaging using high axial resolution fiber-based visible-light OCT

Pi¹,

Camino²,

Zhang³

et al. 2017

Self Cite

Optical coherence tomography using visible-light sources can increase the axial resolution without the need for broader spectral bandwidth. Here, a high-resolution, fiberbased, visible-light optical coherence tomography system is built and used to image normal retina in rats and blood vessels in chicken embryo. In the rat retina, accurate segmentation of retinal layer boundaries and quantification of layer thicknesses are accomplished. Furthermore, three distinct capillary plexuses in the retina and the choriocapillaris are identified and the characteristic pattern of the nerve fiber layer thickness in rats is revealed. In the chicken embryo model, the microvascular network and a venous bifurcation are examined and the ability to identify and segment large vessel walls is demonstrated. References and links1. J. M. Schmitt, "Optical coherence tomography (OCT): a review," IEEE J. Sel. Top. Quantum Electron. 5(4), 1205-1215 (1999 457-463 (2002). 5. W. Drexler, U. Morgner, R. K. Ghanta, F. X. Kärtner, J. S. Schuman, and J. G. Fujimoto, "Ultrahigh-resolution ophthalmic optical coherence tomography," Nat. Med. 7(4), 502-507 (2001). 6. V. J. Srinivasan, D. C. Adler, Y. Chen, I. Gorczynska, R. Huber, J. S. Duker, J. S. Schuman, and J. G. Fujimoto, "Ultrahigh-speed optical coherence tomography for three-dimensional and en face imaging of the retina and optic nerve head," Invest. Ophthalmol. Vis. Sci. 49(11), 5103-5110 (2008).