The OCT Angiography Revolution: 5 Emerging Themes

Ehlers, Justis P.

doi:10.1016/j.oret.2017.09.007

Cited by 5 publications

(2 citation statements)

References 21 publications

(28 reference statements)

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“…Projection artifacts are of particular importance, because of their potential to produce a pseudoflow signal that can be misinterpreted as CNV formation, with consequent needless initiation of anti-VEGF therapy and misinterpretation of response to therapy in established CNV cases. 4 , 10 , 11 Projection-artifact origin is dual-pronged and is caused by close proximity of a hyperreflective structure to the overlying SCP and DCP. This generates bidirectional scattering of incident light rays by the blood vessels onto the underlying hyperreflective static tissue and again of the back-reflected light from the same tissue as it traverses the vessel layers.…”

Section: Introductionmentioning

confidence: 99%

Customized Slab-Segmentation Method for Projection-Artifact Elimination in Best Vitelliform Macular Dystrophy: A Swept-Source Optical Coherence Tomography Angiography Study

Moussa¹,

Leila²,

Moussa³

et al. 2021

OPTH

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Purpose To assess the efficacy of customized slab segmentation in eliminating projection artifacts in swept-source optical coherence tomography angiography (SS-OCTA) images of Best vitelliform macular dystrophy (BVMD). Methods Prospective case series including different stages of BVMD. We analyzed SS-OCTA images for flow signals in the outer retina and coregistered B-scan images for distortion of the segmentation slabs defining the outer retina. We applied a customized method for slab realignment whenever BVMD lesions produced distortion of the slabs. Afterward, we checked the images to determine whether the previously noted flow signal had persisted or disappeared, described as “true flow” or “pseudoflow”, respectively. Categorical variables were analyzed with X 2 or Fisher’s exact tests, while quantitative variables were analyzed with independent t -test at p <0.05. Results The study included 39 eyes of 22 patients. We detected BVMD patterns I (dome-shaped hyperreflective lesion without neurosensory retinal detachment), II (knob-like hyperreflective lesion with localized neurosensory retinal detachment), and III (heterogeneous scattered hyperreflective material) in 49%, 23%, and 28% of eyes, respectively. Pseudoflow was evident mostly in eyes with pattern II lesions, presence of flow signal within BVMD lesions, and lesions whose height represented >80% of the retinal thickness ( p <0.001). Conclusion Customized slab segmentation is effective in eliminating projection artifact in SS-OCTA images of BVMD. Summary Projection artifact is a significant confounding factor in emerging SS-OCTA technology through production of pseudoflow signals that can lead to misinterpretation of images of BVMD lesions. The present study proposes a customized method for correction of segmentation errors to eliminate projection artifacts in SS-OCTA images of BVMD patients.

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Section: Introductionmentioning

confidence: 99%

Customized Slab-Segmentation Method for Projection-Artifact Elimination in Best Vitelliform Macular Dystrophy: A Swept-Source Optical Coherence Tomography Angiography Study

Moussa¹,

Leila²,

Moussa³

et al. 2021

OPTH

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“…Other diseases that can benefit from the use of HSI fundus cameras for their evaluation are those affecting the choroid. This structure can be partially visualized with OCT (central peak wavelength 1060, [113]) or the novel OCT-Angiography [114], although they only provide good qualitative but limited quantitative morphological information (like thickness). However, when imaging the choroid with these conventional techniques, a great part of light is easily lost due to scattering and attenuation from pigment in the RPE and from dense microvasculature in the choriocapillaris [115].…”

Section: Diagnosis Of Retinal Diseases With Fundus Camerasmentioning

confidence: 99%

Hyperspectral imaging system for the fast recording of the ocular fundus

Alterini

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Vision loss affects physical, psychological, and emotional wellbeing and social life as well. High life expectancy and health policies are translated into an aging population worldwide, which has higher risk of eye’s disorders and diseases. Therefore, new systems able to contribute at non-invasive objective diagnosis of ocular diseases are demanded. In this context, optical imaging techniques have a primary role as they allow obtaining information from almost any part of the eye. In particular, many important eye and systemic diseases early manifest themselves in the retina and, since the pioneer study of Helmholtz, many resources have been spent to acquire good images of the ocular fundus. In common clinics, fundus photography is restricted to color imaging sensors with only three spectral bands, and, due to metamerism, many structures might remain hidden. Recently, hyperspectral imaging techniques have come to view as a promising and powerful tool for the spectral analysis of several retinal diseases, increasing the amount of information extractable from fundus photography. However, in the literature, examples are restricted to the visible range of the electromagnetic spectrum, have few bands and/or make use of modified commercial fundus cameras. Accordingly, the goal of this project is to build a novel hyperspectral fundus camera based on light-emitting diodes allowing the fast imaging of the retina both in the visible and in the near infrared region of the spectrum, which has never been explored, through a considerable number of spectral bands. This fundus camera has been designed, tested and developed with new custom-made illumination and detection strategies combined with novel cutting- edge technology at the Center for Sensors, Instruments and Systems Development (CD6) of the Universitat Politècnica de Catalunya (UPC, Terrassa). Finally, after a scrupulous clinical study carried out at the Instituto de Microcirugía Ocular (IMO, Barcelona) and at the University Vision Center of UPC (CUV-UPC, Terrassa), qualitative and quantitative results are presented for healthy and diseased eyes. The available spectroscopic information and the visualization of retinal structures and lesions, especially those affecting the choroidal vasculature and retinal pigment epithelium that are hardly visible in conventional color fundus images, underline the clinical potential of this system as a new tool for ophthalmic diagnosis. La pèrdua de visió afecta el benestar físic, psicològic i emocional, i també la vida social de les persones. La llarga esperança de vida i les polítiques de salut es tradueixen en un envelliment de la població a tot el món, la qual presenta un major risc de patir trastorns i malalties oculars. Per tant, es requereixen nous sistemes capaços de contribuir al diagnòstic objectiu no invasiu d'aquestes malalties. En aquest context, les tècniques d’imatge òptica tenen un paper primordial, ja que permeten obtenir informació de gairebé qualsevol part de l’ull. En particular, moltes malalties oculars i sistèmiques importants es manifesten primerencament a la retina i, des de l’estudi pioner de Helmholtz, s’han gastat molts recursos per adquirir bones imatges del fons ocular. Tradicionalment, a les clíniques oftalmològiques, la fotografia de fons d'ull es fa amb sensors d'imatge en color amb només tres bandes espectrals i, a causa del metamerisme, algunes estructures poden romandre amagades. Recentment, les tècniques d’imatge hiperspectral s’han mostrat com una eina prometedora per a l’anàlisi espectral de la retina, augmentant la quantitat d’informació que es pot extreure de la fotografia del fons d'ull. Tanmateix, a la literatura, els exemples es restringeixen al rang visible de l’espectre electromagnètic, tenen poques bandes i/o fan ús de càmeres de fons d'ull comercials modificades. En conseqüència, l’objectiu d’aquest projecte és construir una nova càmera de fons d'ull hiperspectral basada en díodes emissors de llum que permetin obtenir una imatge ràpida de la retina tant a la regió visible com a la de l’infraroig proper de l’espectre, que mai no s’ha explorat, a través d’un nombre considerable de bandes espectrals. Aquesta càmera de fons d'ull ha estat dissenyada i desenvolupada amb noves estratègies d’il·luminació i detecció fetes a mida i combinades amb nova tecnologia d’avantguarda al Centre de Desenvolupament de Sensors, Instrumentació i Sistemes (CD6) de la Universitat Politècnica de Catalunya (UPC, Terrassa). Finalment, després de la realització d’un estudi clínic detallat portat a terme a l’Institut de Microcirurgia Ocular (IMO, Barcelona) i al Centre Universitari de la Visió de la UPC (CUV-UPC, Terrassa), en aquesta tesi es presenten resultats qualitatius i quantitatius tant per a ulls sans com amb malalties de retina. La informació espectroscòpica i la visualització d’estructures i lesions de la retina, especialment aquelles que afecten la vasculatura de coroides i a l’epiteli pigmentari de la retina que són difícilment visibles en les imatges convencionals del fons d'ull en color, posen de manifest el potencial clínic d’aquest sistema com a nova eina per al diagnòstic oftalmològic

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