1. 1-24 of 1028 1 2 3 4 ... 41 42 43 »
    1. Application of optical coherence tomography to study the structural features of oral mucosa in biopsy tissues of oral dysplasia and carcinomas

      Application of optical coherence tomography to study the structural features of oral mucosa in biopsy tissues of oral dysplasia and carcinomas

      Objective: This study aims to examine the ability of optical coherence tomography (OCT) to differentiate ex vivo epithelial structure of benign disorders, dysplastic, and oral squamous cell carcinoma (OSCC) in comparison with the structure of normal marginal mucosa of oral biopsies. As a secondary objective, we examined the inter- and intra-observer variations of OCT measurements of two calibrated assessors. Materials and methods: Oral biopsies (n = 44) were scanned using the swept source OCT (SSOCT) and grouped by pathology diagnosis to benign, dysplasia or carcinoma. Two trained and calibrated assessors scored on the five OCT variables: thickness of keratin layer (KL ...

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    2. Classification of pachychoroid on optical coherence tomography using deep learning

      Classification of pachychoroid on optical coherence tomography using deep learning

      Purpose Pachychoroid is characterized by dilated Haller vessels and choriocapillaris attenuation that are seen on optical coherence tomography (OCT) B-scans. This study investigated the feasibility of using deep learning (DL) models to classify pachychoroid and non-pachychoroid eyes from OCT B-scan images. Methods In total, 1898 OCT B-scan images were collected from eyes with macular diseases. Images were labeled as pachychoroid or non-pachychoroid based on strict quantitative and qualitative criteria for multimodal imaging analysis by two retina specialists. DL models were trained (80%) and validated (20%) using pretrained convolutional neural networks (CNNs). Model performance was assessed using an independent test set ...

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    3. Online measurement of floc size, viscosity, and consistency of cellulose microfibril suspensions with optical coherence tomography

      Online measurement of floc size, viscosity, and consistency of cellulose microfibril suspensions with optical coherence tomography

      In this study, cellulose microfibril (CMF) suspensions were imaged during pipe flow at consistencies of 0.4%, 1.0%, and 1.6% with optical coherence tomography (OCT) to obtain images of the structure and the local velocity of the suspension. The viscosities obtained by combining pressure loss measurement with the OCT velocity data showed typical shear thinning behavior and were in excellent agreement with viscosities obtained with ultrasound velocity profiling. The structural OCT images were used to calculate the radial and the axial floc sizes of the suspension. A fit of power law to the geometrical floc size–shear stress ...

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    4. Structural OCT Parameters Associated with Treatment Response and Macular Neovascularization Onset in Central Serous Chorioretinopathy

      Structural OCT Parameters Associated with Treatment Response and Macular Neovascularization Onset in Central Serous Chorioretinopathy

      Introduction: This study aimed to assess quantitative factors associated with treatment response and macular neovascularization (MNV) onset in central serous chorioretinopathy (CSC) through an artificial intelligence-based approach. Methods: The study was designed as an interventional, prospective case series with a planned follow-up of 36 months. We included only eyes demonstrating the first episode of CSC. All the patients underwent eplerenone or photodynamic therapy (PDT) treatment. Eyes developing MNV underwent anti-VEGF injections. We developed an artificial intelligence-based model to assess predictive quantitative structural optical coherence tomography (OCT) factors related to treatment response and onset of MNV. Main outcome measures were best-correct ...

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    5. Comparable neointimal healing in patients with stable coronary lesions and acute coronary syndrome: 3-month optical coherence tomography analysis

      Comparable neointimal healing in patients with stable coronary lesions and acute coronary syndrome: 3-month optical coherence tomography analysis

      We aimed to assess a possible difference of the neointimal coverage status and its quality after implantation of the current-generation metallic stents in patients with acute coronary syndrome (ACS) vs. stable coronary lesions (non-ACS). We comprehensively analyzed three prospective single-center observational studies RESTORE (UMIN000033009), HEAL-BioFreedom (UMIN000029692), and HEAL-BioFreedom ACS (UMIN000034769). All patients who received successful optical coherence tomography (OCT) examination at planned 3-month follow-up after stent implantation were analyzed. Study population was divided into two groups, ACS vs. non-ACS groups. We evaluated standard OCT variables, coverage percent, and the quantitative light property values including light intensity, attenuation, and backscatter of ...

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    6. Automatic screening of tear meniscus from lacrimal duct obstructions using anterior segment optical coherence tomography images by deep learning

      Automatic screening of tear meniscus from lacrimal duct obstructions using anterior segment optical coherence tomography images by deep learning

      Purpose We assessed the ability of deep learning (DL) models to distinguish between tear meniscus of lacrimal duct obstruction (LDO) patients and normal subjects using anterior segment optical coherence tomography (ASOCT) images. Methods The study included 117 ASOCT images (19 men and 98 women; mean age, 66.6 ± 13.6 years) from 101 LDO patients and 113 ASOCT images (29 men and 84 women; mean age, 38.3 ± 19.9 years) from 71 normal subjects. We trained to construct 9 single and 502 ensemble DL models with 9 different network structures, and calculated the area under the curve (AUC), sensitivity ...

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    7. Spectral domain optical coherence tomography findings of patients with pars planitis and risk factors affecting visual acuity

      Spectral domain optical coherence tomography findings of patients with pars planitis and risk factors affecting visual acuity

      Purpose: To evaluate spectral domain optical coherence tomography (SD-OCT) findings of 42 eyes with pars planitis and to identify risk factors affecting visual acuity. Methods: Medical records and SD-OCT findings were retrospectively reviewed. Results: Mean best-corrected visual acuity (BCVA) was 0.248 ± 0.3 on the logMAR scale at baseline. SD-OCT findings included epiretinal membrane (ERM) in 16 (38.1%) eyes, loss of normal foveal contour appearance in 8 (19.0%), ellipsoid zone (EZ) damage in 5 (11.9%), external limiting membrane (ELM) damage in 3 (7.1%), disruption of retinal pigment epithelium (RPE) in 2 (4.8%), and macular ...

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    8. Optical coherence tomography angiography in preterm-born children with retinopathy of prematurity

      Optical coherence tomography angiography in preterm-born children with retinopathy of prematurity

      To describe the foveal avascular zone (FAZ) and vessel density (VD) in the superficial and deep capillary plexus in children with a history of prematurity on optical coherence tomography angiography (OCTA) and their correlation with gestational age (GA) and birth weight (BW). Methods We enrolled 81 preterm- and eight term-born children in this prospective observational study. The Optovue RTVue AVANTI (Optovue Inc., Fremont, CA) was used to procure the OCTA images. The 3 × 3 mm scan protocol centered on the fovea and the central 1 mm of the grid along with the FAZ of the superficial capillary plexus (SCP) and ...

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      Mentions: Optovue
    9. Quantification of retinal microvascular parameters by severity of diabetic retinopathy using wide-field swept-source optical coherence tomography angiography

      Quantification of retinal microvascular parameters by severity of diabetic retinopathy using wide-field swept-source optical coherence tomography angiography

      Purpose: To investigate the diagnostic utility of microvascular parameters for grading the severity of diabetic retinopathy (DR) with a range of views using wide-field swept-source optical coherence tomography angiography (SS-OCTA). Methods: This retrospective study grouped 235 eyes with diabetes into the five grades: diabetes without retinopathy (no-DR), mild non-proliferative DR (NPDR), moderate NPDR, severe NPDR, and proliferative DR (PDR). Foveal avascular zone (FAZ) metrics, vessel density (VD), and the capillary nonperfusion area (NPA) were quantified with a customized, semiautomatic software algorithm. Regions of interest were selected from three rectangular fields of different sizes (i.e., 3 × 3 mm 2 , 6 ...

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    10. Two-dimensional correlation (2D) method for improving the accuracy of OCT-based noninvasive blood glucose concentration (BGC) monitoring

      Two-dimensional correlation (2D) method for improving the accuracy of OCT-based noninvasive blood glucose concentration (BGC) monitoring

      The optical scattering coefficient (μ s ) in the dermis layer of human skin obtained with optical coherence tomography (OCT) has shown to have a strong correlation with the blood glucose concentration (BGC), which can be used for noninvasive BGC monitoring. Unfortunately, the nonhomogeneity in the skin may cause inaccuracies for the BGC analysis. In this paper, we propose a 2D correlation analysis method to identify 2D regions in the skin with μ s sensitive to BGC variations and only use data in these regions to calculate μ s for minimizing the inaccuracy induced by nonhomogeneity and therefore improving the accuracy of OCT-based BGC ...

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    11. Feasibility study to improve deep learning in OCT diagnosis of rare retinal diseases with few-shot classification

      Feasibility study to improve deep learning in OCT diagnosis of rare retinal diseases with few-shot classification

      Deep learning (DL) has been successfully applied to the diagnosis of ophthalmic diseases. However, rare diseases are commonly neglected due to insufficient data. Here, we demonstrate that few-shot learning (FSL) using a generative adversarial network (GAN) can improve the applicability of DL in the optical coherence tomography (OCT) diagnosis of rare diseases. Four major classes with a large number of datasets and five rare disease classes with a few-shot dataset are included in this study. Before training the classifier, we constructed GAN models to generate pathological OCT images of each rare disease from normal OCT images. The Inception-v3 architecture was ...

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      Mentions: Cleveland Clinic
    12. Optical Coherence Tomography in Retinopathy of Prematurity (Book Chapter)

      Optical Coherence Tomography in Retinopathy of Prematurity (Book Chapter)

      Retinopathy of prematurity is a vasoproliferative condition characterized by abnormal vascularization of the retina which may lead to tractional retinal detachment. Timely screening and treatment with laser and/or anti-vascular endothelial growth factor agents help prevent blindness. While bedside indirect ophthalmoscopy remains the gold standard for screening, optical coherence tomography has emerged as a new modality for understanding the pathogenesis of retinopathy of prematurity, providing in-vivo monitoring, and evaluating subclinical findings. This chapter provides an overview of optical coherence tomography in retinopathy of prematurity, including available models and adjustments in the neonatal population, differences between preterm, term and adult foveal ...

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    13. Retinal layers in prolactinoma patients: a spectral-domain optical coherence tomography study

      Retinal layers in prolactinoma patients: a spectral-domain optical coherence tomography study

      Purpose: Prolactinoma is a type of pituitary tumour that produces an excessive amount of the hormone prolactin. It is the most common type of hormonally-active pituitary tumour. These tumours can cause ocular complications such as vision loss and visual fields (VF) defect. In this study, we aimed to evaluate the thickness of chorioretinal layers in patients with prolactinoma. Methods: We enrolled 63 eyes of 32 prolactinoma patients and 36 eyes of 18 age and gender-matched healthy controls. All participants underwent complete hormonal and ophthalmological examination, including spectral-domain optical coherence tomography (SD-OCT) and VF test.The complete biochemical response was defined ...

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    14. Optical coherence tomography-guided percutaneous coronary intervention: a review of current clinical applications

      Optical coherence tomography-guided percutaneous coronary intervention: a review of current clinical applications

      Optical coherence tomography (OCT) is an emerging high-resolution intravascular imaging modality that can provide physicians with critical information, thereby enabling precise characterization of plaque morphology and luminal geometry and facilitating pre-intervention lesion assessment. As OCT has a higher sensitivity for lipid-rich plaque characterization than intravascular ultrasound, vulnerable plaque detection by OCT has thus been investigated. By evaluating both the calcium thickness and arc, OCT can be the ideal method for determining both the indication and endpoint of rotational atherectomy for calcified lesions prior to stent implantation. OCT has become applicable for the optimization of stent implantation with immediate and semi-automatic ...

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    15. Intraoperative optical coherence tomography-assisted displacement of prepapillary membrane in eyes with optic disc pit maculopathy

      Intraoperative optical coherence tomography-assisted displacement of prepapillary membrane in eyes with optic disc pit maculopathy

      Purpose: To determine the efficacy of displacing a prepapillary membrane during vitrectomy assisted by intraoperative optical coherence tomography (OCT) to treat eyes with optic disc pit maculopathy. Method: Pars plana vitrectomy was performed with 27-gauge instruments on 4 eyes of 4 consecutive patients for optic disc pit maculopathy with retinoschisis and foveal detachment. After creating a posterior vitreous detachment, the prepapillary membrane was made visible by brilliant blue G staining. The membrane was peeled from the central retinal vessel and inverted and placed over intraretinal clefts or stuffed into the optic disc pit. These procedures were guided by intraoperative OCT ...

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    16. Investigation of Gd2O3: Er3+/Yb3+ Upconversion Nanoparticles (UCNPs) as a Multi‐model Contrast Agent for Functional Optical Coherence Tomography

      Investigation of Gd2O3: Er3+/Yb3+ Upconversion Nanoparticles (UCNPs) as a Multi‐model Contrast Agent for Functional Optical Coherence Tomography

      Currently, upconversion nanoparticles (UCNPs) implanted as a contrast agent for optical coherence tomography (OCT) system due to its biocompatibility, anti-stock emission, narrow emission bandwidth non-photobleaching effects etc., but it was not used as multi model imaging probe. We synthesized multimodal imaging probe having upconversion property along with paramagnetic property and used as dual contrast agents for Photothermal Optical Coherence Tomography (PTOCT) and Magnetomotive Optical Coherence Tomography (MMOCT). The synthesized Gd 2 O 3 :Er 3+ /Yb 3+ UCNPs shows the bright yellow upconversion emission, biocompatibility with hydrophilic property. A custom built SSOCT setup modified for PTOCT and MMOCT imaging along ...

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      Mentions: Raju Poddar
    17. Integrated System for Combined Optical Coherence Tomography-Raman Spectroscopy of Neocaridina denticulate sinensis

      Integrated System for Combined Optical Coherence Tomography-Raman Spectroscopy of Neocaridina denticulate sinensis

      Optical coherence tomography (OCT) and Raman spectroscopy (RS) can be complementary biological tissue optical analysis methods. To study the internal structure and tissue compositions of biological samples, an OCT-RS system was built to carry out OCT section imaging and RS analysis in common. Neocaridina denticulate sinensis were collected regularly for morphological observation by OCT imaging and biochemical investigation based on the Raman spectra. The internal structure of the N. denticulate sinensis was imaged by OCT, and the morphology of the tissues and the position in the body were distinguished according to the gray scale changes. The imaging depth along the ...

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    18. The vessel density of the superficial retinal capillary plexus as a new biomarker in cerebral small vessel disease: an optical coherence tomography angiography study

      The vessel density of the superficial retinal capillary plexus as a new biomarker in cerebral small vessel disease: an optical coherence tomography angiography study

      Background: Optical coherence tomography angiography (OCTA) is a novel and noninvasive technique for the quantitative assessment of retinal microvascular perfusion. Since the retinal and cerebral small vessels share similar embryological origins, anatomical features, and physiological properties, altered retinal microvasculature might provide a new perspective on the mechanisms of cerebral small vessel disease (CSVD). Objective: We aimed to evaluate retinal vessel density (VD) in patients with CSVD using OCTA and identify associations with cerebral magnetic resonance imaging (MRI) markers and cognitive function. Methods: We prospectively recruited 47 CSVD patients and 30 healthy controls (HCs) to participate in the study. All participants ...

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    19. Clinical significance of microvessels detected by in vivo optical coherence tomography within human atherosclerotic coronary arterial intima: a study with multimodality intravascular imagings

      Clinical significance of microvessels detected by in vivo optical coherence tomography within human atherosclerotic coronary arterial intima: a study with multimodality intravascular imagings

      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 µm detected over three or more frames in OCT. We compared the total volume of microvessels with tissue component such as fibrotic ...

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    20. Quantitative evaluation of retinal and choroidal changes in Fabry disease using optical coherence tomography angiography

      Quantitative evaluation of retinal and choroidal changes in Fabry disease using optical coherence tomography angiography

      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 ...

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    21. Optical coherence tomography parameters as predictors of treatment response to a 577-nm subthreshold micropulse laser in chronic central serous chorioretinopathy

      Optical coherence tomography parameters as predictors of treatment response to a 577-nm subthreshold micropulse laser in chronic central serous chorioretinopathy

      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 ...

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    22. Application of Polarization Sensitive-Optical Coherence Tomography to the Assessment of Phase Retardation in Subpleural Cancer in Rabbits

      Application of Polarization Sensitive-Optical Coherence Tomography to the Assessment of Phase Retardation in Subpleural Cancer in Rabbits

      Background: Polarization sensitive-optical coherence tomography (PS-OCT) provides the unique advantage of being able to measure the optical characteristics of tissues by using polarized light. Although the well-organized fibers of healthy muscle can change the polarization states of passing light, damaged tissue has different behaviors. There are studies on optical imaging methods applied to the respiratory organs; however, they are restricted to structural imaging. In particular, the intercostal muscle situated under the pleura is very challenging to visualize due to the difficulty of access. Method: In this study, PS-OCT was used to identify subpleural cancer in male New Zealand white rabbits ...

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    23. Investigation of the Clinical Potential of Polarization-Sensitive Optical Coherence Tomography in a Laryngeal Tumor Model

      Investigation of the Clinical Potential of Polarization-Sensitive Optical Coherence Tomography in a Laryngeal Tumor Model

      BACKGROUND: The vocal cord tissue consists of three anatomical layers from the surface to deep inside: the epithelium that contains almost no collagen, the lamina propria that is composed of abundant collagen, and the vocalis muscle layer. It is clinically important to visualize the tissue microstructure using a non-invasive method, especially in the case of vocal cord nodules or cancer, since histological changes in each layer of the vocal cord cause changes in the voice. Polarization-sensitive optical coherence tomography (PS-OCT) enables phase retardation measurement to evaluate birefringence of tissue with varied organization of collagen fibers in different tissue layers. Therefore ...

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