1. 1-24 of 132 1 2 3 4 5 6 »
    1. Diagnosis of Occlusal Caries with Dynamic Slicing of 3D Optical Coherence Tomography Images

      Diagnosis of Occlusal Caries with Dynamic Slicing of 3D Optical Coherence Tomography Images

      Detecting the extent of occlusal caries is a clinically important but challenging task required for treatment decision making. The aim of this study was to assess the diagnostic power of 3D swept-source optical coherence tomography (OCT) for evaluation of occlusal caries in comparison with X-ray radiography. Extracted human molars not exhibiting American Dental Association (ADA) criteria advanced caries were mounted in a silicone block and digital dental radiographs were captured from the buccal side. Subsequently, occlusal surfaces were scanned with a prototype Yoshida Dental OCT. Thirteen examiners evaluated the presence and extent of caries on radiographs and dynamically sliced 3D ...

      Read Full Article
    2. Special Issue "Development and Application of Imaging Analysis in Ocular Diseases"

      Special Issue "Development and Application of Imaging Analysis in Ocular Diseases"

      Dear Colleagues, The eye is a complex organ that is capable of turning light into sight, allowing us to interpret our surroundings by working similarly to the conventional camera, which gathers, focuses, and transmits light through a lens. Various analyses relying on image-processing algorithms have been proposed to efficiently examine subtle changes in the eye to diagnose ocular diseases. Also, numerous studies have shown that the vessels and neural layers in the eye reflect what is going on in other organs, specifically the heart and brain. Images from the eye have become enormous troves of data for algorithm development in ...

      Read Full Article
    3. Short-Term Effects of Dark Chocolate on Retinal and Choriocapillaris Perfusion in Young, Healthy Subjects Using Optical Coherence Tomography Angiography

      Short-Term Effects of Dark Chocolate on Retinal and Choriocapillaris Perfusion in Young, Healthy Subjects Using Optical Coherence Tomography Angiography

      (1) Aim: Contrasting results have been published on the effect of dark chocolate on visual function. The aim of this study was to evaluate retinal and choriocapillaris perfusion, using optical coherence tomography angiography (OCT-A), and visual function in healthy subjects following dark chocolate ingestion. (2) Methods: This prospective randomized study was carried out on 18 healthy young subjects at the St. Andrea Hospital, Sapienza, University of Rome. Visual acuity assessment and a complete ophthalmologic examination were carried out at baseline. In session one, each subject was randomized to eat either a 100 g dark chocolate bar or a 100 g ...

      Read Full Article
    4. Parafoveal and Peripapillary Perfusion Predict Visual Field Recovery in Chiasmal Compression due to Pituitary Tumors

      Parafoveal and Peripapillary Perfusion Predict Visual Field Recovery in Chiasmal Compression due to Pituitary Tumors

      Background: To evaluate the potential of vessel density alterations for predicting postoperative visual field (VF) improvement in chiasmal compression using optical coherence tomography angiography (OCT-A). Methods: The study investigated 57 eyes of 57 patients diagnosed with pituitary tumors and 42 eyes of 42 age and refractive error matched controls. All eyes with chiasmal compression for which preoperative optical coherence tomography (OCT) and OCT-A, and pre- and postoperative VF data were available. Preoperative vessel densities of superficial retinal capillary plexus (SRCP), deep retinal capillary plexus (DRCP), and radial peripapillary capillary (RPC) segment were utilized by OCT-A. Results: Preoperative peripapillary retinal nerve ...

      Read Full Article
    5. MDAN-UNet: Multi-Scale and Dual Attention Enhanced Nested U-Net Architecture for Segmentation of Optical Coherence Tomography Images

      MDAN-UNet: Multi-Scale and Dual Attention Enhanced Nested U-Net Architecture for Segmentation of Optical Coherence Tomography Images

      Optical coherence tomography (OCT) is an optical high-resolution imaging technique for ophthalmic diagnosis. In this paper, we take advantages of multi-scale input, multi-scale side output and dual attention mechanism and present an enhanced nested U-Net architecture (MDAN-UNet), a new powerful fully convolutional network for automatic end-to-end segmentation of OCT images. We have evaluated two versions of MDAN-UNet (MDAN-UNet-16 and MDAN-UNet-32) on two publicly available benchmark datasets which are the Duke Diabetic Macular Edema (DME) dataset and the RETOUCH dataset, in comparison with other state-of-the-art segmentation methods. Our experiment demonstrates that MDAN-UNet-32 achieved the best performance, followed by MDAN-UNet-16 with smaller ...

      Read Full Article
    6. Choroidal Vascularity Index: An In-Depth Analysis of This Novel Optical Coherence Tomography Parameter

      Choroidal Vascularity Index: An In-Depth Analysis of This Novel Optical Coherence Tomography Parameter

      Remarkable improvements in optical coherence tomography (OCT) technology have resulted in highly sophisticated, noninvasive machines allowing detailed and advanced morphological evaluation of all retinal and choroidal layers. Postproduction semiautomated imaging analysis with dedicated public-domain software allows precise quantitative analysis of binarized OCT images. In this regard, the choroidal vascularity index (CVI) is emerging as a new imaging tool for the measurement and analysis of the choroidal vascular system by quantifying both luminal and stromal choroidal components. Numerous reports have been published so far regarding CVI and its potential applications in healthy eyes as well as in the evaluation and management ...

      Read Full Article
    7. Fourier-Domain OCT Imaging of the Ocular Surface and Tear Film Dynamics: A Review of the State of the Art and an Integrative Model of the Tear Behavior during the Inter-Blink Period and Visual Fixation

      Fourier-Domain OCT Imaging of the Ocular Surface and Tear Film Dynamics: A Review of the State of the Art and an Integrative Model of the Tear Behavior during the Inter-Blink Period and Visual Fixation

      In the last few decades, the ocular surface and the tear film have been noninvasively investigated in vivo, in a three-dimensional, high resolution, and real-time mode, by optical coherence tomography (OCT). Recently, OCT technology has made great strides in improving the acquisition speed and image resolution, thus increasing its impact in daily clinical practice and in the research setting. All these results have been achieved because of a transition from traditional time-domain (TD) to Fourier-domain (FD) technology. FD-OCT devices include a spectrometer in the receiver that analyzes the spectrum of reflected light on the retina or ocular surface and transforms ...

      Read Full Article
    8. Tandem Mach Zehnder Directional Coupler Design and Simulation on Silicon Platform for Optical Coherence Tomography Applications

      Tandem Mach Zehnder Directional Coupler Design and Simulation on Silicon Platform for Optical Coherence Tomography Applications

      We design and compare the splitting ratio wavelength flatness of directional coupler (DC), Mach-Zehnder directional coupler (MZDC), and tandem MZDC. All coupler responses are analyzed, and tandem MZDC performance is the best in the wavelength insensitivity compared with the other two. An MZDC with any coupling ratio could be utilized to match the maximum flatness in a 40-nm wavelength range. To extend a broad flatness range, the tandem MZDC is proposed and still follows the Mach Zehnder structure taking two MZDCs as couplers connected through a decoupled region. Unlike DC, MZDC with the flat wavelength response has a non-linear output ...

      Read Full Article
    9. Highly Stable All-Fiber-Ring Short-Cavity Continuously Tuned Swept Source

      Highly Stable All-Fiber-Ring Short-Cavity Continuously Tuned Swept Source

      In this study, we present a swept source that can intelligently control its sweeping speed while satisfying the commercial stability and miniaturization standards. The source’s central wavelength of the output spectrum is 1300 nm and spectral width is greater than 100 nm. Meanwhile, the scan frequency can be adjusted to range from 20 to 100 kHz, and the stability degree of the optical capacity is less than 0.34%. Additionally, this study establishes a numerical model for the swept-source optical coherence tomography (SS–OCT) system and introduces a numerical simulation of the signal produced during the OCT imaging process ...

      Read Full Article
    10. Angiographic Imaging of an In Vivo Mouse Brain as a Guiding Star for Automatic Digital Refocusing in OCT

      Angiographic Imaging of an In Vivo Mouse Brain as a Guiding Star for Automatic Digital Refocusing in OCT

      A method allows the extraction of the recovery factor that maximizes the image contrast of OCT (optical coherence tomography) and/or OCTA (OCT angiography) of a living subject is proposed in this study. Due to the finite depth of focus in imaging optics, the volume OCT imaging suffers from blurriness in the lateral resolution. By utilizing the digital hologram method or angular spectrum method, the blurred image can be refocused. However, for in vivo OCT imaging, evaluation of the image focus is not easy, owing to the cloudy structure of the brain. In the proposed method, the blood flow signals ...

      Read Full Article
    11. Post-Processing Method for Image Reconstruction Enhancement in Integrating-Bucket-Based Full-Field Optical Coherence Tomography

      Post-Processing Method for Image Reconstruction Enhancement in Integrating-Bucket-Based Full-Field Optical Coherence Tomography

      An integrating-bucket method is widely used as a reconstruction tool for full-field optical coherence tomography (FF-OCT). However, it requires high-precision adjustments of the phase modulation parameters. If the parameters are not optimal, the reconstructed tomogram will incur severe artifacts. We propose a post-processing method for removing or reducing such artifacts by utilizing a correction factor extracted from a pre-reconstructed tomogram. FF-OCT imaging created using a coin verifies the effectiveness of the method not only for a single en face image but also for an entire 3-D image. It is expected that the proposed method will expand the application of FF-OCT ...

      Read Full Article
    12. Functional and Structural Reliability of Optic Nerve Head Measurements in Healthy Eyes by Means of Optical Coherence Tomography Angiography

      Functional and Structural Reliability of Optic Nerve Head Measurements in Healthy Eyes by Means of Optical Coherence Tomography Angiography

      Background and Objectives : the aim of the study was to evaluate the repeatability and reproducibility of optical microangiography (OMAG)-based optical coherence tomography angiography (OCTA) in the optic nerve head (ONH) and radial peripapillary capillary (RPC) perfusion assessment of healthy eyes. Materials and Methods : in this observational study, a total of 40 healthy subjects underwent ONH evaluation, using an OMAG-based OCTA system at baseline (T 0 ), after 30 min (T 1 ), and after 7 days (T 2 ). The main outcome measures were the vessel density (VD) and flux index (FI) of the RPCs, as well as peri-papillary retinal nerve fibre ...

      Read Full Article
    13. Infracyanine Green vs. Brilliant Blue G in Inverted Flap Surgery for Large Macular Holes: A Long-Term Swept-Source OCT Analysis

      Infracyanine Green vs. Brilliant Blue G in Inverted Flap Surgery for Large Macular Holes: A Long-Term Swept-Source OCT Analysis

      Background and Objectives: To compare the long-term toxicity of infracyanine green (IFCG) to brilliant blue G (BBG) in inverted internal limiting membrane flap surgery (I-ILMFS) for large, full-thickness macular holes (FTMHs). Materials and Methods: Prospective randomized study including 39 eyes with ≥ 400 µm idiopathic FTMH who underwent I-ILMFS with either IFCG or BBG. Postoperative 6- and 12-month corrected distance visual acuity (CDVA), closure rate, and swept-source optical coherence tomography parameters, including ellipsoid zone (EZ) and external limiting membrane (ELM) mean defect length, central foveal thicknesses (CFT), parafoveal macular thickness (MT), ganglion cells and inner plexiform layer (GCL++) thickness, and peripapillary ...

      Read Full Article
    14. Morpho-Functional Evaluation of Full-Thickness Macular Holes by the Integration of Optical Coherence Tomography Angiography and Microperimetry

      Morpho-Functional Evaluation of Full-Thickness Macular Holes by the Integration of Optical Coherence Tomography Angiography and Microperimetry

      (1) Objective: To use optical coherence tomography angiography (OCTA) and microperimetry (MP) to evaluate the correlation between retinal structure and function in patients with idiopathic, full-thickness macular holes (FTMHs) (2) Methods: This prospective, observational study included 11 eyes of 10 patients with FTMHs evaluated before surgery using OCTA and MP. MP sensitivity maps were superimposed and registered on slabs corresponding to superficial capillary plexus (SCP) and deep capillary plexus (DCP) on OCTA, and on the outer plexiform layer (OPL) and the Henle fiber layer (HFL) complex in en face OCT. On these maps, mean retinal sensitivity was calculated at 2 ...

      Read Full Article
    15. Widefield Swept Source OCTA in Retinitis Pigmentosa

      Widefield Swept Source OCTA in Retinitis Pigmentosa

      1) Background: To evaluate superficial capillary plexus (SCP), deep capillary plexus (DCP), choriocapillaris (CC), perfusion density (PD), and vessel length density (VLD) in macular and near/mid periphery regions in patients with retinitis pigmentosa (RP) using widefield swept source optical coherence tomography angiography (WSS-OCTA). (2) Methods: Twelve RP patients (20 eyes) and 20 age-matched subjects (20 eyes) were imaged with the SS-OCTA system (PLEX Elite 9000, Carl Zeiss Meditec Inc., Dublin, CA, USA). Quantitative analysis was performed in the macular and peripheral regions. The main outcome measures were SCP, DCP, CC, PD, and VLD in central and peripheral areas. (3 ...

      Read Full Article
    16. Demonstration of Optical Coherence Tomography Guided Big Bubble Technique for Deep Anterior Lamellar Keratoplasty (DALK)

      Demonstration of Optical Coherence Tomography Guided Big Bubble Technique for Deep Anterior Lamellar Keratoplasty (DALK)

      Deep anterior lamellar keratoplasty (DALK) is a highly challenging procedure for cornea transplant that involves removing the corneal layers above Descemet’s membrane (DM). This is achieved by a “big bubble” technique where a needle is inserted into the stroma of the cornea down to DM and the injection of either air or liquid. DALK has important advantages over penetrating keratoplasty (PK) including lower rejection rate, less endothelial cell loss, and increased graft survival. In this paper, we successfully designed and evaluated the optical coherence tomography (OCT) distal sensor integrated needle for a precise big bubble technique. We successfully used ...

      Read Full Article
    17. Detection of Choroidal Neovascularization by Optical Coherence Tomography Angiography with Assistance from Use of the Image Segmentation Method

      Detection of Choroidal Neovascularization by Optical Coherence Tomography Angiography with Assistance from Use of the Image Segmentation Method

      Optical coherence tomography angiography (OCTA) is a popular medical imaging technology that can quickly establish a three-dimensional model of the fundus without dye injection. However the number of images in a model is quite large, so finding the lesions through image processing technology can greatly reduce the time required for the judgment of the condition. This paper proposes a method for finding choroidal neovascularization (CNV) in OCTA images. Among the several characteristics of CNV, the larger turning angle of blood vessels is a relatively clear feature, so we will use this property to find out whether there is CNV in ...

      Read Full Article
    18. OCT-Based Periodontal Inspection Framework

      OCT-Based Periodontal Inspection Framework

      Periodontal diagnosis requires discovery of the relations among teeth, gingiva (i.e., gums), and alveolar bones, but alveolar bones are inside gingiva and not visible for inspection. Traditional probe examination causes pain, and X-ray based examination is not suited for frequent inspection. This work develops an automatic non-invasive periodontal inspection framework based on gum penetrative Optical Coherence Tomography (OCT), which can be frequently applied without high radiation. We sum up interference responses of all penetration depths for all shooting directions respectively to form the shooting amplitude projection. Because the reaching interference strength decays exponentially with tissues’ penetration depth, this projection ...

      Read Full Article
    19. Use of Optical Coherence Tomography in a Patient with Erosive Oral Lichen Planus Treated with Low-Level Laser Therapy. Preliminary Findings

      Use of Optical Coherence Tomography in a Patient with Erosive Oral Lichen Planus Treated with Low-Level Laser Therapy. Preliminary Findings

      Clinical studies have demonstrated the effectiveness of low-level laser therapy (LLLT) in patients with unresponsive oral lichen planus (OLP). OCT can reveal, in real time, the architecture of epithelial and sub-epithelial tissues and surrounding structures [1]. Aim of the present work was to assess the in-vivo changes of oral mucosa before and after LLLT treatment in a patient affected by erosive OLP.

      Read Full Article
    20. GaAs-Based InPBi Quantum Dots for High Efficiency Super-Luminescence Diodes

      GaAs-Based InPBi Quantum Dots for High Efficiency Super-Luminescence Diodes

      InPBi exhibits broad and strong photoluminescence at room temperature, and is a potential candidate for fabricating super-luminescence diodes applied in optical coherence tomography. In this paper, the strained InPBi quantum dot (QD) embedded in the AlGaAs barrier on a GaAs platform is proposed to enhance the light emission efficiency and further broaden the photoluminescence spectrum. The finite element method is used to calculate the strain distribution, band alignment and confined levels of InPBi QDs. The carrier recombinations between the ground states and the deep levels are systematically investigated. A high Bi content and a flat QD shape are found preferable ...

      Read Full Article
    21. Optical Coherence Tomography Angiography Imaging in Inherited Retinal Diseases

      Optical Coherence Tomography Angiography Imaging in Inherited Retinal Diseases

      Optical coherence tomography angiography (OCTA) is a novel, noninvasive imaging modality that allows depth-resolved imaging of the microvasculature in the retina and the choroid. It is a powerful research tool to study the pathobiology of retinal diseases, including inherited retinal dystrophies. In this review, we provide an overview of the evolution of OCTA technology, compare the specifications of various OCTA devices, and summarize key findings from published OCTA studies in inherited retinal dystrophies including retinitis pigmentosa, Stargardt disease, Best vitelliform macular dystrophy, and choroideremia. OCTA imaging has provided new data on characteristics of these conditions and has contributed to a ...

      Read Full Article
    22. Early retinal flow changes after vitreoretinal surgery in idiopathic epiretinal membrane using swept source optical coherence tomography angiography

      Early retinal flow changes after vitreoretinal surgery in idiopathic epiretinal membrane using swept source optical coherence tomography angiography

      (1) Background: The aim of this observational cross-sectional work was to investigate early retinal vascular changes in patients undergoing idiopathic epiretinal membrane (iERM) surgery using swept source optical coherence tomography angiography (SS-OCTA); (2) Methods: 24 eyes of 24 patients who underwent vitrectomy with internal limiting membrane (ILM) peeling were evaluated pre- and postoperatively using SS-OCTA system (PLEX Elite 9000, Carl Zeiss Meditec Inc., Dublin, CA, USA). For each eye, five 6x6-mm OCTA volume scans were acquired by two observers independently. The en face images of superficial capillary plexus (SCP) were then exported to imageJ and a semi-automated algorithm was used ...

      Read Full Article
    23. Automatic Identification and Intuitive Map Representation of the Epiretinal Membrane Presence in 3D OCT Volumes

      Automatic Identification and Intuitive Map Representation of the Epiretinal Membrane Presence in 3D OCT Volumes

      Optical Coherence Tomography (OCT) is a medical image modality providing high-resolution cross-sectional visualizations of the retinal tissues without any invasive procedure, commonly used in the analysis of retinal diseases such as diabetic retinopathy or retinal detachment. Early identification of the epiretinal membrane (ERM) facilitates ERM surgical removal operations. Moreover, presence of the ERM is linked to other retinal pathologies, such as macular edemas, being among the main causes of vision loss. In this work, we propose an automatic method for the characterization and visualization of the ERM’s presence using 3D OCT volumes. A set of 452 features is refined ...

      Read Full Article
    24. Pre-, Intra-, and Post-Operative Evaluation of Extraocular Muscle Insertions Using Optical Coherence Tomography: A Comparison of Four Devices

      Pre-, Intra-, and Post-Operative Evaluation of Extraocular Muscle Insertions Using Optical Coherence Tomography: A Comparison of Four Devices

      OCT (optical coherence tomography) is widely used in ophthalmology and pediatric ophthalmology, but limited research has been done on the use of OCT in strabismus. This study investigates the use of different OCT machines to image rectus muscle insertions pre-, intra-, and post-operatively in pediatric strabismus patients. The OCT machines used in the study were a Bioptigen (Leica Microsystems Inc., Buffalo Grove, IL, USA), Spectralis HRA+OCT with Anterior Segment Module (Heidelberg Engineering, Heidelberg, Germany), Visante (Carl Zeiss, Oberkochen, Germany), and Zeiss Rescan 700 (Carl Zeiss, Oberkochen, Germany). Measurements from the machines were compared with the caliper distance measured during ...

      Read Full Article
    1-24 of 132 1 2 3 4 5 6 »
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks