Optical Coherence Tomography News

Time 2021-01-11 12:04:53

Web Name: Optical Coherence Tomography News

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Increased regurgitant blood flow has been linked to endocardial cushion defects and resultant congenital heart diseases (CHDs). Prenatal alcohol exposure (PAE) has been shown to alter early blood flow resulting in abnormal endocardial cushions and CHDs. Compounds, including folic acid (FA), mitigate PAE effects and prevent CHDs, but few studies have assessed their effects on blood flow. We modeled binge drinking in quail embryos at gastrulation. Embryos were exposed to ethanol alone, FA (3.2 g/egg) alone, and the two simultaneously. We quantified in cardiac looping stages (equivalent to 4 weeks of human gestation) regurgitant blood flow with Doppler ... A study on the applicability of optical coherence tomography imaging for questioned documents examination, particularly identification documents (national ID cards and passports) has just been published by researchers from the Applied Optics group, the Forensic Science Research group in our School, and Foster and Freeman, Ltd., a manufacturer of forensic science lab equipment. This is a unique study for the group and the wider school, where Photonics was so exquisitely used for Forensic Science research. It is also another step in our work together with Foster and Freeman, which should hopefully enable even more fruitful collaboration in the future. This ... In this work, we present a significant step toward in vivo ophthalmic optical coherence tomography and angiography on a photonic integrated chip. The diffraction gratings used in spectral-domain optical coherence tomography can be replaced by photonic integrated circuits comprising an arrayed waveguide grating. Two arrayed waveguide grating designs with 256 channels were tested, which enabled the first chip-based optical coherence tomography and angiography in vivo three-dimensional human retinal measurements. Design 1 supports a bandwidth of 22 nm, with which a sensitivity of up to 91 dB (830 W ) and an axial resolution of 10.7 m was measured. Design 2 ... Significance: Surgical microscopes provide adjustable magnification, bright illumination, and clear visualization of the surgical field and have been increasingly used in operating rooms. State-of-the-art surgical microscopes are integrated with various imaging modalities, such as optical coherence tomography (OCT), fluorescence imaging, and augmented reality (AR) for image-guided surgery. Aim: This comprehensive review is based on the literature of over 500 papers that cover the technology development and applications of surgical microscopy over the past century. The aim of this review is threefold: (i) providing a comprehensive technical overview of surgical microscopes, (ii) providing critical references for microscope selection and system development ... nanoplus , a German manufacturer ( sales@nanoplus.us ), launches superluminescent diodes (SLD) in the spectral band from 760 nm to 2900 nm. The devices complement nanoplus well-known product portfolio of Distributed Feedback Lasers (DFB). They used their expertise as technology leader for DFB lasers to create broadband light sources in the near infrared. For more than 20 years, we have been manufacturing DFB and Fabry Perot (FP) lasers with excellent performance - the same technology is used for our SLDs. The new SLD devices combine the proven beam quality of nanoplus DFB lasers with the large spectrum of LEDs. The figures show ... Background: There is an urgent need to develop a non-invasive imaging technique for detecting colorectal dysplasia and cancer. Technology for early and real-time microscopic assessments to select the most representative biopsy sites would also be of clinical value. In this study, we explored the sensitivity of optical coherence tomography (OCT) in detecting local lesions to demonstrate its potential for the early detection of colorectal dysplasia and cancer. Methods: An azoxymethane/dextran sodium sulfate mouse model of colorectal carcinogenesis was utilized. Mice were imaged by OCT, and colorectal tissue sections were observed with hematoxylin and eosin staining. The results of the ... Percutaneous coronary intervention (PCI) in patients with chronic kidney disease is associated with a high-risk of contrast-induced nephropathy. We describe a case of ultra-low contrast PCI guided using optical coherence tomography using normal saline for clearance complicated by distal wire perforation treated with embolization. ( Level of Difficulty: Intermediate. ) Von Hippel-Lindau (VHL) disease is an autosomal dominant genetic disease caused by VHL gene mutation. Retinal hemangioblastomas (RH) are vascularized tumors and represent the main ocular manifestation of the disease. Histopathologically, RH are composed of capillary vessels and stromal cells, the neoplastic population of the lesion. The origin of these stromal cells remains controversial, even if they are hypothesized to be glial cells. The aim of the present study was to investigate neuronal and microvascular changes of the peripapillary retinal nerve fiber layer, in which glial cells, neurons and capillaries (the radial peripapillary capillary plexus) interact. VHL patients with or ... Background To explore the relationship between corneal biomechanical parameters and corneal sublayer thickness using corneal visualization Scheimpflug technology (Corvis ST) and ultrahigh-resolution optical coherence tomography (UHR-OCT) in clinical and suspected keratoconus and normal eyes. Methods Cross-sectional prospective study. A total of 94 eyes of 70 participants were recruited. Twenty five eyes of 19 keratoconus patients, 52 eyes of 34 patients showing high risk of developing keratoconus according to the Belin/Ambrosio Enhanced Ectasia Display, and each eye of 17 normal subjects were enrolled. All participants underwent Corvis ST, Pentacam, and UHR-OCT examinations at the same time. Stiffness parameter A1 (SP-A1 ... Optical coherence tomography (OCT) imaging widely used in retinal examinations yields high resolution cross-sectional scans of the retina. As a key indicator for studying the development of retinopathy, the change of layer thickness needs to be accurately measured. Although many deep learning-based segmentation methods have been developed, most of them do not explicitly consider the strict order of the retina layers, which easily leads to topological errors. In this paper, we propose a novel segmentation framework that employs the distance maps of layer surfaces to convert the segmentation task into multitasking problem for classification and regression, and obtains the topology-guaranteed ... Upconversion nanoparticles (UCNPs) are widely recognized exogenous contrast agents for bioimaging. Swept source optical coherence tomography (SSOCT) is a non-invasive imaging tool commissioned for cross-sectional imaging of the biological sample. We present polymerically modified UCNPs as a potential contrast agent for SSOCT. In this communication, functionalized NaYF4: Ho3+/Yb3+ UCNPs were synthesized for more bioavailability with a coating of two different polymers namely, polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP). Time-dependent diffusion dynamics of functionalized UCNPs were performed in-vivo with a mice model. Imaging was performed with both inactive and excited UCNPs. A separate optical system was developed ... A 17-year-old male with acute myeloid leukemia (AML), presented with diminution of vision OS for 6 months. The best-corrected visual acuity was 6/9 OD and 4/60 OS. Anterior segment OU was normal. Fundus revealed pale disc OD with multiple areas of well-circumscribed pigmentary changes [Figure 1] a and vitreous hemorrhage OS. The patient underwent OS 25-G vitrectomy after informed consent. After clearing hemorrhage and induction of posterior vitreous detachment (PVD), multiple pigmented areas similar to OD including one at macula were noted [Figure 1] b. Intraoperative optical coherence tomography (I-OCT) revealed them to be areas of regressed sub-internal ... Deepening the understanding of scaling processes would facilitate the improvement of membrane distillation (MD) as a promising technique for sustainable development. This study investigated the scaling of calcium sulfate in MD via an approach based on optical coherence tomography (OCT). The OCT-based characterization enabled an analysis that correlated the flux decline with the morphological evolution of the scaling layer. It was revealed by this analysis that the reduction in the evaporation rate could be dominated by different mechanisms as the crystalline particles grew and deposited on the membrane surface; the striping phenomenon visualized by mapping the local growth rates provided ... Optical coherence tomography (OCT) is one of the most commonly used ophthalmic diagnostic techniques. Macular Edema (ME) is the swelling of the macular region in the eye. Segmentation of the fluid region in the retinal layer is an important step in detecting lesions. However, manual segmentation is often a time consuming and subjective process. In this paper, an improved U-Net segmentation method is proposed. In this method, the attention mechanism is introduced to automatically locate the fluid region, which avoids the problem of excessive calculation in multi-stage methods. At the same time, the use of dense skip connections which combines ... Abstract: Background:There is increasing evidence that Alzheimer s disease (AD) patients may present decreased cerebral blood perfusion before pathological brain changes. Using the retina as a window to the brain, we can study disorders of the central nervous system through the eyes. Objective:This study aim ed to investigate differences in retinal structure and vessel density (VD) between patients with mild AD and healthy controls (HCs). Furthermore, we explored the relationship between retinal VD and cognitive function. Methods:We enrolled 37 patients with AD and 29 age-matched HCs who underwent standard ophthalmic optical coherence tomography angiography (OCTA) for evaluation ... Background: The purpose of this study was to investigate peripapillary vessel density of primary angle closure glaucoma (PACG) eyes in quadrant and clock-hour sectors, and the diagnostic ability of peripapillary vessel density was also studied. Methods: This was a cross-sectional study on forty-one PACG patients(50 eyes)and twenty-seven healthy subjects(27 eyes). The optic disc was imaged using a 1050-nm-wavelength swept-source optical coherence tomography system (DRI OCT Triton, TOPCON). Peripapillary vessel density was quantified by imageJ software. Characteristics of peripapillary vessel density of quadrant and clock-hour sectors were analyzed, and diagnostic capability was evaluated by areas under the receiver ... The significance of microvessels within atherosclerotic plaques is not yet fully clarified. Associated with plaque vulnerability. The aim of this study is to examine tissue characteristics of plaque with microvessels detected by optical coherence tomography (OCT) by use of a commercially available color-coded intravascular ultrasound (IVUS) and coronary angioscopy (CAS). The subjects examined comprised of 44 patients with stable angina pectoris who underwent percutaneous coronary intervention. Microvessels were defined as a tiny tubule with a diameter of 50-300 m detected over three or more frames in OCT. We compared the total volume of microvessels with tissue component such as fibrotic ... Significance: Adaptive optics optical coherence tomography (AO-OCT) technology enables non-invasive, high-resolution three-dimensional (3D) imaging of the retina and promises earlier detection of ocular disease. However, AO-OCT data are corrupted by eye-movement artifacts that must be removed in post-processing, a process rendered time-consuming by the immense quantity of data. Aim: To efficiently remove eye-movement artifacts at the level of individual A-lines, including those present in any individual reference volume. Approach: We developed a registration method that cascades (1) a 3D B-scan registration algorithm with (2) a global A-line registration algorithm for correcting torsional eye movements and image scaling and generating global ... Embryos are growing organisms with highly heterogeneous properties in space and time. Understanding the mechanical properties is a crucial prerequisite for the investigation of morphogenesis. During the last 10 years, new techniques have been developed to evaluate the mechanical properties of biological tissues in vivo. To address this need, we employed a new instrument that, via the combination of micro‐indentation with Optical Coherence Tomography (OCT), allows us to determine both, the spatial distribution of mechanical properties of chick embryos, and the structural changes in real‐time. We report here the stiffness measurements on the live chicken embryo, from the ... To examine the retinal and choroidal changes in patients with Fabry disease (FD) using optical coherence tomography angiography (OCTA). FD patients and age- and sex-matched healthy subjects were enrolled. A detailed ophthalmological examination was performed for all participants. The retinal thickness, ganglion cell layer with inner plexiform layer (GCIPL) thickness, choroidal thickness (CT), vessel length density (VLD), vessel perfusion density (VPD), and foveal avascular zone (FAZ) were analyzed in a detailed way with OCTA. Moreover, all FD patients underwent several laboratory tests to evaluate systemic conditions. A total of 54 subjects comprising 26 FD patients and 28 normal controls were ... To determine the relation between retinal microstructural changes and the response to 577-nm subthreshold micropulse laser (SML) treatment in chronic central serous chorioretinopathy (cCSC). This retrospective study included 39 eyes of 39 patients with cCSC, treated with the 577-nm SML. The eyes were evaluated in three groups: complete remission, partial remission, and failure groups. The presence of some baseline retinal microstructural changes, thickness of the outer nuclear layer (ONL), status of the ellipsoid zone (EZ), and retinal pigment epithelium (RPE) were evaluated. The changes in central macular thickness (CMT), subretinal fluid (SRF) height, and best-corrected visual acuity (BCVA) were calculated ... Ultrahigh resolution optical coherence tomography (UHR-OCT) for differentiating pituitary gland versus adenoma tissue has been investigated for the first time, indicating more than 80% accuracy. For biomarker identification, OCT images of paraffin embedded tissue are correlated to histopathological slices. The identified biomarkers are verified on fresh biopsies. Additionally, an approach, based on resolution modified UHR-OCT ex vivo data, investigating optical performance parameters for the realization in an in vivo endoscope is presented and evaluated. The identified morphological features cell groups with reticulin framework detectable with UHR-OCT showcase a promising differentiation ability, encouraging endoscopic OCT probe development for in vivo application.Share your journal articles, press releases, job & studentship openings, and more with the OCT community. Click here.

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