1. 1-24 of 905 1 2 3 4 ... 36 37 38 »
    1. Factors associated with macular vessel density measured by optical coherence tomography angiography in healthy and glaucomatous eyes

      Factors associated with macular vessel density measured by optical coherence tomography angiography in healthy and glaucomatous eyes

      Purpose To investigate factors associated with macular vessel density and to analyze their effects according to glaucoma stage. Study design Retrospective cross-sectional study. Methods A total of 72 healthy eyes and 147 open-angle glaucomatous eyes were studied. All eyes underwent optical coherence tomography and visual field examinations. Clinical variables were compared according to the glaucoma stage. Relationships between macular vessel density (mVD) and other variables were analyzed using linear regression and segmented analyses. Results Age ( P = 0.010) and signal strength ( P < 0.001) were associated with macular vessel density in healthy eyes. In glaucomatous eyes, age, signal strength, ganglion ...

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    2. Early vascular response of ultra-thin bioresorbable polymer sirolimus-eluting stents assessed by optical frequency domain imaging: the EVALUATION study

      Early vascular response of ultra-thin bioresorbable polymer sirolimus-eluting stents assessed by optical frequency domain imaging: the EVALUATION study

      This study aimed to evaluate the early vascular response of ultra-thin strut bioresorbable polymer sirolimus-eluting stents (BP SES) using optical frequency domain imaging (OFDI). Ultra-thin strut BP SES have superior outcomes in terms of efficacy and safety endpoints when compared to other thin strut new-generation stents. However, the factors contributing to the superiority of BP SES over other thin strut new-generation stents are unclear. A total of 32 patients with multivessel disease requiring staged procedures at 1 month were enrolled from 3 cardiovascular institutions; of these, 31 were immediately assessed by OFDI ( n  = 31). All patients were assessed at 1 ...

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    3. Topographic analysis of retinal and choroidal microvasculature according to diabetic retinopathy severity using optical coherence tomography angiography

      Topographic analysis of retinal and choroidal microvasculature according to diabetic retinopathy severity using optical coherence tomography angiography

      Purpose To investigate the topographic changes in the retinal capillary plexus and the choriocapillaris according to the severity of diabetic retinopathy (DR) using optical coherence tomography angiography (OCTA). Methods Subjects were recruited and classified into one of the following four groups: normal controls ( n = 52), diabetes without DR ( n = 49), non-proliferative DR ( n = 51) and proliferative DR ( n = 38). Using OCTA, the superficial capillary plexus (SCP), deep capillary plexus (DCP) and the choriocapillaris vessel densities were measured and compared in different macular areas: the fovea (1-mm diameter circular area), parafovea (1–3-mm diameter ring) and perifovea (3–6-mm ring). Results ...

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    4. Connector sensors for permittivity-based thrombus monitoring in extracorporeal life support

      Connector sensors for permittivity-based thrombus monitoring in extracorporeal life support

      Extracorporeal circulation is vital in cardiovascular surgery, but thrombus formation at connector interface is a major threat. Optical coherence tomography (OCT) is presently used to monitor thrombogenesis at connectors, but it is expensive to install and complex to use. This study fabricated and evaluated a connector sensor for real-time permittivity-based thrombus monitoring at tube–connector interface. Computational simulations were initially done to pre-evaluate the applicability of connector sensor. The sensor was fabricated by incorporating two stainless steel electrodes on acrylic tube for measuring permittivity changes at the tube–connector interface. OCT images were also taken from the interface at intervals ...

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    5. Two different populations of Müller cells stabilize the structure of the fovea: an optical coherence tomography study

      Two different populations of Müller cells stabilize the structure of the fovea: an optical coherence tomography study

      Purpose To document with spectral-domain optical coherence tomography the structural stabilization of the fovea and the sealing of outer macular defects by Müller cells. Methods A retrospective case series of 45 eyes of 34 patients is described. Results In cases of a cystic disruption of the foveola as in macular telangiectasia type 2 and vitreomacular traction, the Müller cell cone provides the structural stability of the fovea. In cases of a detachment or disruption of the Müller cell cone, e.g., in foveal pseudocysts, outer lamellar holes, and degenerative and tractional lamellar holes, Müller cells of ...

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    6. Optical coherence tomography in adult adrenoleukodystrophy: a cross-sectional and longitudinal study

      Optical coherence tomography in adult adrenoleukodystrophy: a cross-sectional and longitudinal study

      Background Adrenoleukodystrophy (ALD) encompasses different neurological phenotypes, ranging from the most severe cerebral forms (C-ALD) to the less severe adrenomyeloneuropathy (AMN). As visual system can be varyingly involved, we aimed at exploring whether optical coherence tomography (OCT) may detect retinal abnormalities and their longitudinal changes in adult ALD patients. Methods In this cross-sectional and longitudinal study, we measured the thicknesses of peripapillary retinal nerve fiber layer (pRNFL), macular ganglion cell complex (mGCC), and segmented inner and outer macula at baseline and their changes over time in 11 symptomatic adult ALD males and 10 age- and sex-matched healthy controls. Statistical analyses ...

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    7. Technology in Practical Dermatology (Textbook)

      Technology in Practical Dermatology (Textbook)

      This book provides a complete overview on the latest available technologies in dermatology, while discussing future trends of this ever-growing field. This handy guide provides clinicians and researchers with a clear understanding of the advantages and challenges of laser and imaging technologies in skin medicine today. It also includes a section on imaging techniques for the evaluation of skin tumors, with chapters devoted to dermoscopy, in vivo and ex vivo reflectance confocal microscopy, high frequency ultrasound, optical coherence tomography, and a closing part on latest approaches to wound management. Completed by over 200 clinical images, Current Technology in Practical Dermatology ...

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    8. Optical coherence tomography angiography for detection of macular neovascularization associated with atrophy in age-related macular degeneration

      Optical coherence tomography angiography for detection of macular neovascularization associated with atrophy in age-related macular degeneration

      Purpose To evaluate the ability of optical coherence tomography angiography (OCTA) to detect macular neovascularization (MNV) in eyes with atrophy compared with fluorescein angiography (FA), indocyanine green angiography (ICGA), and optical coherence tomography (OCT). Methods In this prospective study, eyes with MNV and atrophy (termed macular atrophy or MA) secondary to age-related macular degeneration (AMD), and AMD eyes with geographic atrophy (GA) without MNV underwent multimodal imaging with FA, ICGA, structural OCT, and OCTA. The presence of MNV was determined using all imaging modalities by senior retina specialists and was considered the gold standard reference. Each individual imaging modality was ...

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    9. Relationship between vascular densities of choriocapillaris and the whole choroid using OCTA

      Relationship between vascular densities of choriocapillaris and the whole choroid using OCTA

      Purpose To study the vascular density (VD) of choriocapillaris and the whole choroid using optical coherence tomography-angiography (OCTA). Methods Cross-sectional study enrolling healthy individuals between 18 and 35 years old and with an axial length (AL) lower than 26 mm, who were examined with swept-source OCTA Triton DRI (Topcon). Color pictures of both VD were obtained from a fovea-centered 6 × 6 mm macular exam, which were divided into 900 squares and codified into numbers. Results A total of 50 patients (100 eyes) with a mean age of 27.29 ± 3.90 years and a mean AL of 23.67 ± 0 ...

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    10. Retinal microvascular metrics in untreated essential hypertensives using optical coherence tomography angiography

      Retinal microvascular metrics in untreated essential hypertensives using optical coherence tomography angiography

      Purpose To quantify early changes of macular microvascular density, complexity, and peripapillary vessel caliber in hypertension using optical coherence tomography angiography (OCTA). Methods Hypertension (137 eyes) and healthy eyes (79 eyes) as control were involved in this prospective observational study. Indices of the microcirculation included vessel density (VD), skeleton density (SD), vessel diameter index (VDI), fractal dimension (FD) and foveal avascular zone (FAZ) of superficial retinal layer (SRL) and deep retinal layer (DRL), and peripapillary vessel calibers. The correlation of these indices with mean arterial pressure (MAP) and ocular perfusion pressure (OPP) was analyzed. Results Mean VD of DRL, SD ...

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    11. Optical coherence tomography angiography analysis of fabry disease

      Optical coherence tomography angiography analysis of fabry disease

      urpose Fabry disease (FD) is characterized by a deficiency in α-galactosidase A activity that leads to the cumulative deposition of unmetabolized glycosphingolipids within organs, including the vascular endothelium and the eyes. The purpose of this study was to assess the effects of FD on the retinal microvasculature, foveal avascular zone (FAZ), macular thickness and retinal nerve fiber layer (RNFL) using optical coherence tomography angiography (OCT-A). Methods Twenty-five patients (14 female and 11 male; mean age 33.16 ± 11.44) with genetically verified FD were compared with 37 age- and sex-matched healthy controls (mean age 32.36 ± 15.54). The vessel ...

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    12. A Review on Advances in Intra-operative Imaging for Surgery and Therapy: Imagining the Operating Room of the Future

      A Review on Advances in Intra-operative Imaging for Surgery and Therapy: Imagining the Operating Room of the Future

      With the advent of Minimally Invasive Surgery (MIS), intra-operative imaging has become crucial for surgery and therapy guidance, allowing to partially compensate for the lack of information typical of MIS. This paper reviews the advancements in both classical (i.e. ultrasounds, X-ray, optical coherence tomography and magnetic resonance imaging) and more recent (i.e. multispectral, photoacoustic and Raman imaging) intra-operative imaging modalities. Each imaging modality was analyzed, focusing on benefits and disadvantages in terms of compatibility with the operating room, costs, acquisition time and image characteristics. Tables are included to summarize this information. New generation of hybrid surgical room and ...

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    13. Medical Image Enhancement Using Super Resolution Methods

      Medical Image Enhancement Using Super Resolution Methods

      Deep Learning image processing methods are gradually gaining popularity in a number of areas including medical imaging. Classification, segmentation, and denoising of images are some of the most demanded tasks. In this study, we aim at enhancing optic nerve head images obtained by Optical Coherence Tomography (OCT). However, instead of directly applying noise reduction techniques, we use multiple state-of-the-art image Super-Resolution (SR) methods. In SR, the low-resolution (LR) image is upsampled to match the size of the high-resolution (HR) image. With respect to image enhancement, the upsampled LR image can be considered as low quality, noisy image, and the HR ...

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    14. Deep Retinal Diseases Detection and Explainability Using OCT Images

      Deep Retinal Diseases Detection and Explainability Using OCT Images

      Retinal disease classification is an important challenge in computer aided diagnosis (CAD) for medical applications. Eye diseases can cause different symptoms from mild vision problems to complete blindness if it is not timely treated. The early diagnosis is crucial to prevent blindness. In this work, we use deep Convolutional Neural Networks (CNN) on a 4-class classification problem to automatically detect choroidal neovascularization (CNV), diabetic macular edema (DME), drusen, and normal cases using Optical Coherence Tomography (OCT) images. The obtained results achieve state-of-the-art performance and show that the proposed network leads to higher classification rates with an accuracy of 98.46 ...

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    15. Optical Coherence Tomography: Current Applications for the Assessment of Coronary Artery Disease and Guidance of Percutaneous Coronary Interventions

      Optical Coherence Tomography: Current Applications for the Assessment of Coronary Artery Disease and Guidance of Percutaneous Coronary Interventions

      Introduction Coronary angiography (CAG) is the standard modality for assessment of coronary stenoses and intraprocedural guidance of percutaneous coronary interventions (PCI). However, the limitations of CAG are well recognized. Intracoronary imaging (ICI) can potentially overcome these limitations. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are the main ICI techniques utilized in clinical practice. Aim This narrative literature review addresses the current clinical applications of OCT in relation to IVUS and CAG in patients with coronary artery disease (CAD). Items reviewed are: technical implications of OCT and IVUS, lesion characterization and decision-making, stent optimization criteria, post-stenting results, safety in terms ...

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    16. Joint Diabetic Macular Edema Segmentation and Characterization in OCT Images

      Joint Diabetic Macular Edema Segmentation and Characterization in OCT Images

      The automatic identification and segmentation of edemas associated with diabetic macular edema (DME) constitutes a crucial ophthalmological issue as they provide useful information for the evaluation of the disease severity. According to clinical knowledge, the DME disorder can be categorized into three main pathological types: serous retinal detachment (SRD), cystoid macular edema (CME), and diffuse retinal thickening (DRT). The implementation of computational systems for their automatic extraction and characterization may help the clinicians in their daily clinical practice, adjusting the diagnosis and therapies and consequently the life quality of the patients. In this context, this paper proposes a fully automatic ...

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    17. Evaluation of retinal vessel quantity within individual retinal structural layers using optical coherence tomography angiography

      Evaluation of retinal vessel quantity within individual retinal structural layers using optical coherence tomography angiography

      Purpose To evaluate retinal vessel quantity within various retinal structural layers using optical coherence tomography angiography (OCTA). Methods In this IRB-approved study, 22 normal eyes (from 22 subjects) were imaged using the Spectralis OCT2, with a 15 × 15 degree OCTA scan centered on fovea and two additional 15 × 5 degree OCTA scans, displaced temporally and nasally by 15 degrees along the fovea-Bruch’s membrane opening (BMO) axis. Following projection artifact removal (PAR), vessel quantity (i.e., amount of flow signal) within each retinal nuclear and plexiform layer was assessed across the scan and was plotted as a vessel quantity profile ...

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    18. Transfer Learning Coupled Convolution Neural Networks in Detecting Retinal Diseases Using OCT Images

      Transfer Learning Coupled Convolution Neural Networks in Detecting Retinal Diseases Using OCT Images

      Optical coherence tomography (OCT) in diagnosing retinal images is an extensive technique for detecting the wide-ranging diseases related to retina. In this paper, the authors have considered three diseases, viz. diabetic macular edema (DME), choroidal neovascularization (CNV), and drusen. These diseases are classified using six different convolutional neural network (CNN) architectures. The purpose is to compare among the six different CNNs in terms of accuracy, precision, F - measure, and recall. The architectures used are coupled with or without transfer learning, and a comparison has been drawn as to how the CNN architectures work when they are coupled with or without ...

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    19. Altered microvascular density in patients with systemic lupus erythematosus treated with hydroxychloroquine—an optical coherence tomography angiography study

      Altered microvascular density in patients with systemic lupus erythematosus treated with hydroxychloroquine—an optical coherence tomography angiography study

      urpose To evaluate the retinal microvascular density using optical coherence tomography angiography (OCTA) in patients with systemic lupus erythematosus (SLE) treated with hydroxychloroquine (HCQ). Methods Nineteen eyes of 19 patients with SLE (study group) without HCQ retinopathy and 19 eyes of 19 healthy subjects (control group) were included in this study. The study group was divided into patients using HCQ for > 5 years (high-risk group) and < 5 years (low-risk group). The VD data of the 3 × 3 mm OCT angiogram of the superficial capillary plexus (SCP) and the choriocapillaris (VD-CC), the foveal avascular zone (FAZ) area and the central retinal ...

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    20. Evaluation of microvascular changes in optic disc and retina by optical coherence tomography angiography during Valsalva maneuver

      Evaluation of microvascular changes in optic disc and retina by optical coherence tomography angiography during Valsalva maneuver

      Purpose Optical coherence tomography angiography (OCTA) is an increasingly widespread imaging tool that allows the visualization of the microvascular structures of the eye. It should be kept in mind in clinical practice, Valsalva maneuver (VM) may have an effect on OCTA findings. We aimed to evaluate the effect of VM on the optic nerve and retinal blood flow parameters measured by OCTA. Methods Sixty age- and sex-matched healthy volunteers were included into this prospective study. Optic disc status for radial peripapillary capillary (RPC) network [whole image, inside disc and peripapillary capillary densities], superficial and deep capillary plexus whole, foveal, parafoveal ...

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    21. Spectral domain optical coherence tomography findings of patients with ankylosing spondylitis

      Spectral domain optical coherence tomography findings of patients with ankylosing spondylitis

      Purpose The aim of this study is to evaluate the possible effects of (ankylosing spondylitis) AS on choroidal thickness (CT) and other retinal layers using spectral domain optical coherence tomography (SD-OCT). Methods This cross-sectional study group comprised 41 AS patients and age and sex-matched 46 control subjects. None of our patients had active anterior uveitis during the measurements. We evaluated and compared CT, retinal nerve fiber layer (RNFL) thickness, ganglion cell complex (GCC) thickness, focal loss volume (FLV) and global loss volume (GLV) of the participants. Results The CT of the patients at 1500 µm (286.20 µm ± 65.81 ...

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    22. Additional Debulking Efficacy of Low-Speed Rotational Atherectomy After High-Speed Rotational Atherectomy for Calcified Coronary Lesion

      Additional Debulking Efficacy of Low-Speed Rotational Atherectomy After High-Speed Rotational Atherectomy for Calcified Coronary Lesion

      We aimed to evaluate the additional debulking efficacy of low-speed rotational atherectomy (RA) after high-speed RA by using intravascular imaging. A total of 22 severe calcified coronary lesions in 19 patients (age, 74 ± 10 years; 74% male) were retrospectively analyzed. All of these lesions underwent RA under optical coherence tomography (OCT) or optical frequency domain imaging (OFDI) guidance. At first, we performed high-speed RA with 220,000 rpm until the reduction of rotational speed disappeared; then, low-speed RA with 120,000 rpm using the same burr size was performed. OCT or OFDI was performed after both high-speed and low-speed RAs ...

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    23. Optical coherence tomography (OCT) and OCT angiography allow early identification of sickle cell maculopathy in children and correlate it with systemic risk factors

      Optical coherence tomography (OCT) and OCT angiography allow early identification of sickle cell maculopathy in children and correlate it with systemic risk factors

      Purpose To determine the presence of sickle cell retinopathy and maculopathy and to identify associations between markers of hemolysis and systemic and ocular manifestations in children affected by sickle cell disease. Methods Eighteen children with sickle cell disease, aged 5–16 years, underwent complete eye examination including best-corrected visual acuity, slit-lamp biomicroscopy, ophthalmoscopy after pharmacological mydriasis, spectral-domain optical coherence tomography (SD-OCT), and optical coherence tomography angiography (OCTA). Blood test results and clinical history information were collected for each child, including fetal hemoglobin (HbF), hemoglobin (Hb), hematocrit (Htc), mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), reticulocytes percentage (%ret), lactic ...

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    24. Indications for intraoperative anterior segment optical coherence tomography in corneal surgery

      Indications for intraoperative anterior segment optical coherence tomography in corneal surgery

      Purpose Recently, intraoperative optical coherence tomography (iOCT) has evolved in the field of ophthalmic surgery. So far, the use of iOCT was mainly focused to lamellar keratoplasty, especially deep anterior lamellar keratoplasty (DALK) and Descemet membrane endothelial keratoplasty (DMEK). The aim of this study was to report our experiences with iOCT to introduce new possibilities of this application. Methods We used iOCT in 18 patients who underwent the following surgeries: DALK, DMEK, penetrating keratoplasty, autologous limbal transplantation, transscleral suture fixation of a posterior chamber lens, pannus removal on corneal surface and newborn investigation in Peters’ anomaly. We obtained qualitative video ...

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