1. All Articles

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    1. Changes in the Retinal Microvasculature Measured Using Optical Coherence Tomography Angiography According to Age

      Changes in the Retinal Microvasculature Measured Using Optical Coherence Tomography Angiography According to Age

      In this cross-sectional study, we examined age-related changes in the retinal vessels of 100 healthy participants, aged from 5 to 80 years, and divided into four groups (G1, under 20 years of age; G2, from 20 to 39 years of age; G3, from 40 to 59 years of age; G4, age 60 years or older). All subjects underwent swept-source optical coherence tomography (SS-OCT) and OCT angiography (OCTA). The vascular density (VD) of the superficial (SCP) and deep capillary plexus (DCP), and choriocapillaris (CCP) were measured using OCTA. The vascular density of each capillary layer, foveal avascular zone (FAZ) area, ganglion ...

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    2. Direct en-face, speckle-reduced images using angular-compounded Master-Slave optical coherence tomography

      Direct en-face, speckle-reduced images using angular-compounded Master-Slave optical coherence tomography

      In this paper, an angular compounding method to achieve speckle contrast reduction in optical coherence tomography (OCT) imaging is explored in detail. The angular compounding approach involves collecting multiple images at different angles of incidence, registering the images to correct for induced distortions, and then incoherently summing the images to reduce speckle. The method was experimentally demonstrated with a spectrometer-based Master-Slave enhanced OCT instrument capable of directly generating en-face images. We have investigated the impact of the angular range and number of averaged frames on the degree of speckle artefact reduction, as well as the effect on image resolution and ...

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    3. A case report of a recurrent early and late Bioresorbable vascular scaffold thrombosis: serial angiography and optical coherence tomography findings

      A case report of a recurrent early and late Bioresorbable vascular scaffold thrombosis: serial angiography and optical coherence tomography findings

      Background In bioresorbable vascular scaffolds (BVSs), there is some concern about a possible increase in the rate of scaffold thromboses (ScTs). Although several characteristics similarly contribute to the development of both early and late ScTs, there are also clearly different pathomechanisms between the two time-dependent types of thromboses, especially with BVSs. Case presentation We recently experienced a very rare case of a 69-year-old man who had recurrent early and late ScTs with somewhat differing pathomechanisms as assessed by optical coherence tomography (OCT). For the late ScT, OCT identified a scaffold dismantling in the same place that a peri-strut low intensity ...

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    4. Optical coherence tomography angiography as a novel approach to contactless evaluation of sublingual microcirculation: A proof of principle study

      Optical coherence tomography angiography as a novel approach to contactless evaluation of sublingual microcirculation: A proof of principle study

      Microcirculatory disorders are crucial in pathophysiology of organ dysfunction in critical illness. Evaluation of sublingual microcirculation is not routinely conducted in daily practice due to time-consuming analysis and susceptibility to artifacts. We investigated the suitability of optical coherence tomography angiography (OCTA) for contactless evaluation of sublingual microcirculation. Sublingual microcirculation was imaged in 10 healthy volunteers, using an OCTA device and an incident dark field (IDF) illumination microscopy (current gold standard). OCTA images were analyzed with regard to flow density and perfused vessel density (PVD byOCTA ). IDF videos were analyzed following current recommendations. Flow density was automatically extracted from OCTA images ...

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    5. Functional optical coherence tomography and photoacoustic microscopy imaging for zebrafish larvae

      Functional optical coherence tomography and photoacoustic microscopy imaging for zebrafish larvae

      We present a dual modality functional optical coherence tomography and photoacoustic microscopy (OCT-PAM) system. The photoacoustic modality employs an akinetic optical sensor with a large imaging window. This imaging window enables direct reflection mode operation, and a seamless integration of optical coherence tomography (OCT) as a second imaging modality. Functional extensions to the OCT-PAM system include Doppler OCT (DOCT) and spectroscopic PAM (sPAM). This functional and non-invasive imaging system is applied to image zebrafish larvae, demonstrating its capability to extract both morphological and hemodynamic parameters in vivo in small animals, which are essential and critical in preclinical imaging for physiological ...

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    6. Plasma Ceramides in Relation to Coronary Plaque Characterization Determined by Optical Coherence Tomography

      Plasma Ceramides in Relation to Coronary Plaque Characterization Determined by Optical Coherence Tomography

      Plasma ceramides (Cer), a subset of bioactive lipids, have mechanistic links to development of atherosclerosis and are related to major adverse cardiovascular events (MACEs). Previous researches have demonstrated vulnerable plaques contribute to acute cardiovascular events and poor prognosis. This study aimed to explore the associations between Cer and culprit plaque characterizations evaluated by optical coherence tomography (OCT). It was found that plasma Cer are associated with culprit plaque vulnerability evaluated by OCT, providing evidence supporting proatherogenic roles and potential to act as markers for plaque vulnerability of Cer.

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    7. Retinal neurodegeneration in patients with end-stage renal disease assessed by spectral-domain optical coherence tomography

      Retinal neurodegeneration in patients with end-stage renal disease assessed by spectral-domain optical coherence tomography

      Spectral-domain optical coherence tomography (SD-OCT) represents a reliable tool for retinal layer volume and thickness measurement. The aim of this study was to evaluate retinal changes indicating neurodegenerative processes in patients with end-stage renal disease (ESRD) compared to healthy controls. This was a cross-sectional, single-center study comprising 32 ESRD patients and 38 controls. Sectoral retinal nerve fiber layer (RNFL) thickness and retinal layer volumes were obtained by SD-OCT. Age- and gender-adjusted retinal layer volumes such as total retinal volume (p = 0.037), ganglion cell layer volume (GCL, p = 0.003), ganglion cell layer – inner plexiform layer volume (GCL-IPL, p = 0 ...

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    8. Swept-source optical coherence tomography by off-axis Fresnel transform digital holography with an output throughput of 10 Giga voxels per second in real-time

      Swept-source optical coherence tomography by off-axis Fresnel transform digital holography with an output throughput of 10 Giga voxels per second in real-time

      We demonstrate swept-source optical coherence tomography in real-time by high throughput digital Fresnel hologram rendering from optically-acquired interferograms with a high-speed camera. The interferogram stream is spatially rescaled with respect to wavelength to compensate for fieldof-view dilation inherent to discrete Fresnel transformation. Holograms are calculated from an input stream of 16-bit, 1024-by-1024-pixel interferograms recorded at up to 512 frames per second with a digital camera. All calculations are performed by a NVIDIA TITAN Xp graphics card on single-precision floating-point complex-valued arrays (32-bit per quadrature). It allows sustained computation of 1024-by-1024-by-256-voxel volumes at 10 billion voxel/s, from which three perpendicular ...

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    9. Spectral Domain Optical Coherence Tomography Features

      Spectral Domain Optical Coherence Tomography Features

      Purpose: To investigate the long-term incidence and risk factors of macular hole (MH) development in the fellow eyes of patients with unilateral idiopathic MH. Methods: The retrospective case–control study involved the fellow eyes of 215 consecutive patients with idiopathic MH. The patients were classified into two groups according to the presence or development of MH in the fellow eye. The spectral domain optical coherence tomography features and clinical characteristics of each group were compared. Results: Twelve (5.6%) patients presented with bilateral MH at the initial visit, whereas 20 (9.3%) initially unilateral patients developed MH in the fellow ...

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    10. HYPERREFLECTIVE FOVEAL SPOTS IN PATIENTS WITH VITREORETINAL ANOMALIES A Qualitative and Quantitative Analysis

      HYPERREFLECTIVE FOVEAL SPOTS IN PATIENTS WITH VITREORETINAL ANOMALIES A Qualitative and Quantitative Analysis

      Purpose: To describe structural optical coherence tomography (OCT) and OCT angiography features in patients who have developed hyperreflective foveal spots with or without vitreomacular interface abnormalities or with vitreous adhesion alone. Methods: The study design was observational and cross sectional. The presence of defined epiretinal membrane was considered an exclusion criterion. All patients underwent complete ophthalmologic examination, with structural OCT and OCT angiography acquisitions. Both qualitative and quantitative analyses of OCT angiography reconstructions were performed for superficial capillary plexus, deep capillary plexus, and choriocapillaris. Results: Thirty patients (20 men; mean age, 55.2 years) showing hyperreflective foveal spots on structural ...

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    11. OCULAR MANIFESTATIONS OF PORETTI-BOLTSHAUSER SYNDROME: FINDINGS FROM MULTIMODAL IMAGING AND ELECTROPHYSIOLOG

      OCULAR MANIFESTATIONS OF PORETTI-BOLTSHAUSER SYNDROME: FINDINGS FROM MULTIMODAL IMAGING AND ELECTROPHYSIOLOG

      Background/Purpose: Poretti-Boltshauser syndrome is a rare, nonprogressive neurologic syndrome with characteristic cerebellar cysts on neuroimaging due to mutations in LAMA1 . The ophthalmic findings in Poretti-Boltshauser syndrome are not well described. Here, we report the ophthalmic findings from multimodal imaging and electrophysiology of a patient with genetically confirmed Poretti-Boltshauser syndrome . Methods: A 3-year-old boy with confirmed mutations in LAMA1 underwent examination under anesthesia with electroretinography and multimodal imaging including fundus photography, fluorescein angiography , optical coherence tomography , and optical coherence tomography angiography . Results: Dilated fundus examination was notable for retinal vascular anomalies, including a large area of nonperfusion in the temporal ...

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    12. QUANTITATIVE ASSESSMENT OF THE FOVEAL AVASCULAR ZONE USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY BEFORE AND AFTER SURGERY FOR IDIOPATHIC EPIRETINAL MEMBRANE

      QUANTITATIVE ASSESSMENT OF THE FOVEAL AVASCULAR ZONE USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY BEFORE AND AFTER SURGERY FOR IDIOPATHIC EPIRETINAL MEMBRANE

      Purpose: To investigate, using optical coherence tomography angiography , the foveal avascular zone (FAZar), the FAZ perimeter (FAZp), the acircularity index of the FAZ (FAZai), and the density of vessels surrounding the FAZ (FAZvd) before and after idiopathic epiretinal membrane surgery, and associations of these parameters with postoperative best-corrected visual acuity, letter score gain, and central foveal thickness. Methods: We retrospectively reviewed preoperative and postoperative (sixth month) medical records of 28 eyes of 28 patients who undergone epiretinal membrane surgery and had an intact ellipsoid zone. Results: There were significant increases in best-corrected visual acuity, FAZar, and FAZp and decreases in ...

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    13. Myopia and anterior segment optical coherence tomography findings in laser-treated retinopathy of prematurity eyes

      Myopia and anterior segment optical coherence tomography findings in laser-treated retinopathy of prematurity eyes

      Purpose To evaluate structural features and visual outcomes in eyes with a prior history of laser treatment for retinopathy of prematurity (ROP). Methods Laser-treated eyes for type 1 ROP, preterm monitored eyes, and full-term control eyes were included. LogMAR conversion of Snellen best-corrected visual acuity and spherical equivalent based on cycloplegic refraction were measured in children 5-15 years of age. Anterior segment optical coherence tomography (OCT) was used to study structural features, including anterior chamber angle (ACA) in a subset of eyes. Results A total of 50 eyes of 50 patients were included (19 full-term eyes, 19 laser-treated type 1 ...

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    14. NTU scientists develop handheld, high-resolution medical imaging device

      NTU scientists develop handheld, high-resolution medical imaging device

      NTU scientists develop handheld, high-resolution medical imaging device with potential for bedside scanning Scientists at Nanyang Technological University, Singapore (NTU Singapore) have developed the prototype of a handheld medical imaging device that can produce images down to resolutions of 1 to 2 micrometres. This is detailed enough to spot the first signs of tumours in specific cells and is about 100 times higher resolution than what X-Ray, computed tomography (CT) and Magnetic Resonance Imaging (MRI) machines can provide. The technology behind the device is a result of six years of optical imaging research and was jointly developed by a team ...

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    15. Gradient Bosting Classifiers Combining Vessel Density and Tissue Thickness Measurements for Classifying Early to Moderate Glaucoma

      Gradient Bosting Classifiers Combining Vessel Density and Tissue Thickness Measurements for Classifying Early to Moderate Glaucoma

      Purpose To compare gradient boosting classifier (GBC) analysis of optical coherence tomography angiography (OCTA)-measured vessel density (VD) and OCT-measured tissue thickness to standard OCTA VD and OCT thickness parameters for classifying healthy eyes and eyes with early to moderate glaucoma. Design Comparison of diagnostic tools. Methods One-hundred-eight healthy eyes and 193 glaucomatous eyes with OCTA and OCT imaging of the macula and optic nerve head (ONH) were studied. Four GBCs were evaluated that combined 1) all macula VD and thickness measurements (Macula GBC), 2) all ONH VD and thickness measurements (ONH GBC), 3) all VD measurements from the macula ...

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    16. OCT Guided Punctal Stenosis Management

      OCT Guided Punctal Stenosis Management

      The study was conducted on 40 eyes of 24 patients have acquired inflammatory punctal stenosis and 20 eyes of 10 patients of normal asymptomatic subjects as control group. We studied the external punctal diameter, visibility of the internal punctum and punctal depth before treatment using AS-OCT, and then patients were re-evaluated after one month of treatment with preservative free methylprednisolone 5% eye drops.

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    17. Features of cotton wool spots in diabetic retinopathy: a spectral-domain optical coherence tomography angiography study

      Features of cotton wool spots in diabetic retinopathy: a spectral-domain optical coherence tomography angiography study

      Purpose To describe the features of cotton wool spots (CWSs) in diabetic retinopathy (DR) by using spectral-domain optical coherence tomography (SD-OCT) and optical coherence tomography angiography (OCT angiography). Methods We retrospectively studied patients with DR who presented CWSs and had been imaged by SD-OCT angiography. The retinal layer localisation and dimensions of the CWSs were assessed on SD-OCT, while the decorrelation signal generated by the CWSs and the vascular density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus around the CWSs and in the macula were assessed on OCT angiography. Results A total of 87 eyes of ...

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    18. Normative database of peripapillary vessel density measured by optical coherence tomography angiography and correlation study

      Normative database of peripapillary vessel density measured by optical coherence tomography angiography and correlation study

      Purpose: To provide a normative data set of swept-source optical coherence tomography angiography (SS-OCTA) peripapillary vessel density (VD) measurements and assess correlations with age, gender, disc area and axial length (AL). Material and Methods: This was an observational cross-sectional study conducted on 346 right eyes of healthy subjects. Peripapillary SS-OCTA VD measurements were obtained in the retinal superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC) in all four quadrants using the Triton device (Topcon, Nagoya, Japan). AL measurements were made by optical biometry. Results: Mean participant age was 37.7 ±19.8 years (range 5 – 83), AL ...

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    19. Non‐invasive multimodal imaging by integrating optical coherence tomography with autofluorescence imaging for dental applications

      Non‐invasive multimodal imaging by integrating optical coherence tomography with autofluorescence imaging for dental applications

      We report the development of an integrated multi‐functional imaging system capable of providing anatomical (optical coherence tomography, OCT), functional (OCT angiography, OCTA) and molecular imaging (light‐induced autofluorescence, LIAF) for in vivo dental applications. Blue excitation light (405 nm) was used for LIAF imaging, while the OCT was powered by a 1310 nm swept laser source. A red‐green‐blue (RGB) digital camera, with a 450 nm cut‐on broad‐band optical filter, was used for LIAF detection. The exciting light source and camera were integrated directly with the OCT scanning probe. The integrated system used two non‐invasive ...

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    20. Classification of optical coherence tomography images using a capsule network

      Classification of optical coherence tomography images using a capsule network

      Background Classification of optical coherence tomography (OCT) images can be achieved with high accuracy using classical convolution neural networks (CNN), a commonly used deep learning network for computer-aided diagnosis. Classical CNN has often been criticized for suppressing positional relations in a pooling layer. Therefore, because capsule networks can learn positional information from images, we attempted application of a capsule network to OCT images to overcome that shortcoming. This study is our attempt to improve classification accuracy by replacing CNN with a capsule network. Methods From an OCT dataset, we produced a training dataset of 83,484 images and a test ...

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    21. Topographic analysis of macular choriocapillaris flow deficits in diabetic retinopathy using swept–source optical coherence tomography angiography

      Topographic analysis of macular choriocapillaris flow deficits in diabetic retinopathy using swept–source optical coherence tomography angiography

      Background The purpose of this study was to investigate the association between diabetic retinopathy (DR) severity and macular choriocapillaris (CC) flow deficit percentage (FD %) in different macular regions using swept-source optical coherence tomography angiography (SS-OCTA). Methods Diabetic patients with SS-OCTA images were graded by severity and retrospectively assessed. CC FD % was calculated in four different regions of the OCTA image: inner, middle, outer, and full-field region. The generalized estimating equations (GEE) approach for clustered eye data was used to determine effect size and significance of age and disease severity on FD % for each region. Results 160 eyes from 90 total ...

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    22. Randomized comparison of optical coherence tomography versus angiography to guide Bioresorbable vascular scaffold implantation: The OPTICO BVS stud

      Randomized comparison of optical coherence tomography versus angiography to guide Bioresorbable vascular scaffold implantation: The OPTICO BVS stud

      Purpose We investigated whether optical coherence tomography (OCT)-guided bioresorbable vascular scaffolds (BVS) implantation can improve in-scaffold minimal lumen area (MLA) at 6-month compared with angiography guidance. Methods The OPTICO BVS was a randomized, international multicenter, assessor blind, superiority trial comparing OCT- versus angiography-guided percutaneous coronary intervention (PCI) (1:1 allocation) in patients with coronary artery disease undergoing Absorb BVS 1.1 implantation. The primary endpoint was in-scaffold MLA at 6-month. Results The trial was prematurely stopped on May 31, 2017 after enrollment of 38 of 270 planned patients (14%) following the retraction of the device in Europe. Patients were ...

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    23. Three-dimensional visualization of opacifications in the murine crystalline lens by in vivo optical coherence tomography

      Three-dimensional visualization of opacifications in the murine crystalline lens by in vivo optical coherence tomography

      Diagnostic classification techniques used to diagnose cataracts, the world’s leading cause of blindness, are currently based on subjective methods. Here, we present optical coherence tomography as a noninvasive tool for volumetric visualization of lesions formed in the crystalline lens. A custom-made swept-source optical coherence tomography (SS-OCT) system was utilized to investigate the murine crystalline lens. In addition to imaging cataractous lesions in aged wildtype mice, we studied the structure and shape of cataracts in a mouse model of Alzheimer’s disease. Hyperscattering opacifications in the crystalline lens were observed in both groups. Post mortem histological analysis were performed to ...

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    24. Widefield optical coherence tomography angiography for early detection and objective evaluation of proliferative diabetic retinopathy

      Widefield optical coherence tomography angiography for early detection and objective evaluation of proliferative diabetic retinopathy

      Purpose To evaluate the utility of widefield optical coherence tomography angiography (WF-OCTA) compared with clinical examination in grading diabetic retinopathy in patients diagnosed clinically with proliferative diabetic retinopathy (PDR) or severe non-proliferative diabetic retinopathy (NPDR). Design This retrospective observational case series included patients diagnosed clinically with PDR or severe NPDR. Patients underwent standard clinical examination and WF-OCTA imaging (PLEX Elite 9000, Carl Zeiss Meditec AG) using 12×12 montage scans between August 2018 and January 2019. Two trained graders identified neovascularisation at the disc (NVD) and neovascularisation elsewhere (NVE) on WF-OCTA which were compared with the clinical examination, and to ...

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