1. 1-24 of 334 1 2 3 4 ... 12 13 14 »
    1. Preclinical longitudinal imaging of tumor microvascular radiobiological response with functional optical coherence tomography

      Preclinical longitudinal imaging of tumor microvascular radiobiological response with functional optical coherence tomography

      Radiation therapy (RT) is widely used for cancer treatment, alone or in combination with other therapies. Recent RT advances have revived interest in delivering higher dose in fewer fractions, which may invoke both cellular and microvascular damage mechanisms. Microvasculature may thus be a potentially sensitive functional biomarker of RT early response, especially for such emerging RT treatments. However it is difficult to measure directly and non-invasively, and its time course, dose dependencies, and overall importance in tumor control are unclear. We use functional optical coherence tomography for quantitative longitudinal in vivo imaging in preclinical models of human tumor xenografts subjected ...

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    2. Choroidal vascularity index in type-2 diabetes analyzed by swept-source optical coherence tomography

      Choroidal vascularity index in type-2 diabetes analyzed by swept-source optical coherence tomography

      The relationships between changes in choroidal vasculature and the severity of diabetic retinopathy (DR) remain unclear. We assessed choroidal changes in diabetic patients by measuring choroidal vascularity index (CVI) in conjunction with DR stage. In this study, patients with diabetes and healthy controls were retrospectively analyzed. Subjects were divided into seven groups as follows: Healthy controls, no DR, mild/moderate non-proliferative DR (NPDR), severe NPDR, proliferative DR (PDR), panretinal photocoagulation-treated DR, and clinically significant macular edema. The mean CVI values in the above groups were 69.08, 67.07, 66.28, 66.20, 63.48, 65.38, and 66.28 ...

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    3. Universal in vivo Textural Model for Human Skin based on Optical Coherence Tomograms

      Universal in vivo Textural Model for Human Skin based on Optical Coherence Tomograms

      Currently, diagnosis of skin diseases is based primarily on the visual pattern recognition skills and expertise of the physician observing the lesion. Even though dermatologists are trained to recognize patterns of morphology, it is still a subjective visual assessment. Tools for automated pattern recognition can provide objective information to support clinical decision-making. Noninvasive skin imaging techniques provide complementary information to the clinician. In recent years, optical coherence tomography (OCT) has become a powerful skin imaging technique. According to specific functional needs, skin architecture varies across different parts of the body, as do the textural characteristics in OCT images. There is ...

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      Mentions: Saba Adabi
    4. Swept-source and optical coherence tomography angiography in patients with X-linked retinoschisis

      Swept-source and optical coherence tomography angiography in patients with X-linked retinoschisis

      Purpose To explore the structural features of juvenile X-linked retinoschisis (XLRS) using swept-source-optical coherence tomography (SS-OCT) and optical coherence tomography angiography (OCT-A). Design Retrospective, observational cross-sectional study. Patients and methods Nine patients (18 eyes) diagnosed with juvenile XLRS were included. SS-OCT and OCT-A were used to evaluate the characteristics of the inner/outer retina and the choroid. Results SS-OCT showed that the inner nuclear layer (INL) was the most commonly affected area (16/18 eyes; 89%). No significant differences in central macular thickness (CMT) or subfield choroidal thickness (SFCT) were evidenced between eyes (CMT: 364  μ m in the right eye ...

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    5. Response of central serous chorioretinopathy evaluated by multimodal retinal imaging

      Response of central serous chorioretinopathy evaluated by multimodal retinal imaging

      Purpose To identify predictive biomarkers of treatment outcomes by multimodal retinal imaging in patients affected by central serous chorioretinopathy (CSC). Patients and methods In this interventional non-randomized clinical study, 27 treatment-naive CSC patients were prospectively enrolled and treated with oral eplerenone for 5–13 weeks. Primary outcomes included presence of pathological findings on indocyaine green angiography (ICGA), structural optical coherence tomography (OCT) and OCT-angiography (OCT-A) at baseline associated with different response to the treatment. Results A total of 29 eyes of 27 patients (2 females, 25 males) met the inclusion criteria and were included in the study (mean age was ...

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    6. Non-invasive multimodal optical coherence and photoacoustic tomography for human skin imaging

      Non-invasive multimodal optical coherence and photoacoustic tomography for human skin imaging

      The cutaneous vasculature is involved in many diseases. Current clinical examination techniques, however, cannot resolve the human vasculature with all plexus in a non-invasive manner. By combining an optical coherence tomography system with angiography extension and an all optical photoacoustic tomography system, we can resolve in 3D the blood vessels in human skin for all plexus non-invasively. With a customized imaging unit that permits access to various parts of patients’ bodies, we applied our multimodality imaging system to investigate several different types of skin conditions. Quantitative vascular analysis is given for each of the dermatological conditions to show the potential ...

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    7. Multimodal retinal imaging in central serous chorioretinopathy treated with oral eplerenone or photodynamic therapy

      Multimodal retinal imaging in central serous chorioretinopathy treated with oral eplerenone or photodynamic therapy

      Purpose To correlate function and structural optical coherence tomography (OCT) to optical coherence tomography angiography (OCT-A) measures in patients affected by central serous chorioretinopathy (CSC) and to describe their changes after treatments (ie oral eplerenone, half-fluence photodynamic therapy (PDT)). Patients and methods Twenty eyes of 16 consecutive patients with treatment-naïve CSC undergoing either eplerenone or PDT were enrolled in this prospective, observational study. All patients underwent structural OCT and OCT-A at baseline and after therapy at months 1 and 3. Results Eleven eyes of nine patients and nine eyes of seven patients underwent eplerenone or PDT treatment, respectively. Central ...

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    8. Measurement of full-thickness macular hole size using en face optical coherence tomography

      Measurement of full-thickness macular hole size using en face optical coherence tomography

      Purpose To assess the feasibility and interest of measuring macular hole (MH) size using en face optical coherence tomography (OCT) compared with manual diameter measurements on B-scans. Methods Among our previously published series of 100 patients operated for primary MH, patients whose images were acquired with Cirrus 5000 HD-OCT (Carl Zeiss Meditec) with a quality signal strength >5/10 were included. Three segmentations (internal limiting membrane, horizontal, and retinal pigment epithelium (RPE)) were compared for obtaining the most appropriate en face image. MH surface areas were measured using ImageJ software. Mean diameters calculated from surface areas (diameter=2 × √(surface area ...

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    9. In-vivo longitudinal imaging of microvascular changes in irradiated oral mucosa of radiotherapy cancer patients using optical coherence tomography

      In-vivo longitudinal imaging of microvascular changes in irradiated oral mucosa of radiotherapy cancer patients using optical coherence tomography

      Mucositis is the limiting toxicity of radio(chemo)therapy of head and neck cancer. Diagnostics, prophylaxis and correction of this condition demand new accurate and objective approaches. Here we report on an in vivo longitudinal monitoring of the oral mucosa dynamics in 25 patients during the course of radiotherapy of oropharyngeal and nasopharyngeal cancer using multifunctional optical coherence tomography (OCT). A spectral domain OCT system with a specially-designed oral imaging probe was used. Microvasculature visualization was based on temporal speckle variations of the full complex signal evaluated by high-pass filtering of 3D data along the slow scan axis. Angiographic image ...

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    10. Interocular Symmetry of Vascular Density and Association with Central Macular Thickness of Healthy Adults by Optical Coherence Tomography Angiography

      Interocular Symmetry of Vascular Density and Association with Central Macular Thickness of Healthy Adults by Optical Coherence Tomography Angiography

      In order to analyze the interocular correlation of vascular density, foveal avascular zone (FAZ) size, central macular thickness (CMT), and to investigate the relationship between vascular density and CMT in normal eyes, retinal vascular density in superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris (CC) networks, FAZ size, and CMT were visualized by optical coherence tomography (OCT) angiography. A total of 174 eyes of 87 normal Chinese subjects were enrolled in the study. The results showed that FAZ and CMT measurements are not statistically significant between right and left eyes, but right eyes had higher vascular density in ...

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    11. Intraoperative optical coherence tomography to evaluate the effect of the eyelid speculum on corneal pachymetry during accelerated corneal cross-linking (9 mW/cm2)

      Intraoperative optical coherence tomography to evaluate the effect of the eyelid speculum on corneal pachymetry during accelerated corneal cross-linking (9 mW/cm2)

      Purpose To investigate intraoperative anterior segment optical coherence tomography (AS-OCT) to compare pachymetry changes between two methods (group 1: speculum-on, group 2: speculum-off during riboflavin instillation stage) during corneal cross-linking /CXL) (9 mW/cm 2 for 10 min) in keratoconic patients. Methods In this interventional case series, 11 eyes (11 patients) in group 1 and 14 eyes (14 patients) in group 2 were enrolled. Pachymetry measurements by spectral domain OCT was performed at baseline, after epithelial removal, after 30 min of imbibition with riboflavin, and after UV irradiation. Repeated measures analysis of variance was used to compare the trend of ...

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    12. Super-achromatic monolithic microprobe for ultrahigh-resolution endoscopic optical coherence tomography at 800 nm

      Super-achromatic monolithic microprobe for ultrahigh-resolution endoscopic optical coherence tomography at 800 nm

      Endoscopic optical coherence tomography (OCT) has emerged as a valuable tool for advancing our understanding of the histomorphology of various internal luminal organs and studying the pathogenesis of relevant diseases. To date, this technology affords limited resolving power for discerning subtle pathological changes associated with early diseases. In addition, it remains challenging to access small luminal organs or pass through narrow luminal sections without potentially causing trauma to tissue with a traditional OCT endoscope of a 1-1.5 mm diameter. Here we report an ultracompact (520 µm in outer diameter and 5 mm in rigid length) and super-achromatic microprobe made ...

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    13. The structure-function relationship measured with optical coherence tomography and a microperimeter with auto-tracking: the MP-3, in patients with retinitis pigmentosa

      The structure-function relationship measured with optical coherence tomography and a microperimeter with auto-tracking: the MP-3, in patients with retinitis pigmentosa

      The purpose of the current study was to investigate the structure-function relationship in patients with retinitis pigmentosa (RP) using optical coherence tomography and the MP-3 microperimeter. Visual field (VF) measurements were carried out using MP-3 microperimetry and the Humphrey Field Analyzer (HFA, Carl-Zeiss, CA), 22 eyes of 11 patients with a clinical diagnosis of RP, both with the 10-2 test grid pattern. Optical coherence tomography (OCT, Spectralis, Heidelberg, Germany) was also performed and the ellipsoid zone (EZ) was identified in the OCT image. The mean (±SD) number of test points located within the EZ edge was 11.6 (±5.9 ...

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    14. Identifying characteristic features of the retinal and choroidal vasculature in choroideremia using optical coherence tomography angiography

      Identifying characteristic features of the retinal and choroidal vasculature in choroideremia using optical coherence tomography angiography

      Clinical Study Identifying characteristic features of the retinal and choroidal vasculature in choroideremia using optical coherence tomography angiography A Abbouda , A M Dubis , A R Webster & M Moosajee Abstract Purpose Using optical coherence tomography angiography (OCTA) to investigate the area with flow in the superficial retinal vessel network (SVRN) and choriocapillaris (CC) layer among male subjects with choroideremia (CHM), female carriers, and normal controls to identify vascular changes. Patients and methods Images of SRVN and CC layer were acquired in 9 affected males, 5 female carriers, and 14 age- and gender-matched controls using the Angiovue software of the RTVue XR ...

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    15. Precision of a new ocular biometer in eyes with cataract using swept source optical coherence tomography combined with Placido-disk corneal topography

      Precision of a new ocular biometer in eyes with cataract using swept source optical coherence tomography combined with Placido-disk corneal topography

      The present study was to assess the precision (repeatability and reproducibility) of a new optical biometer (OA-2000, Tomey, Japan) based on swept-source optical coherence tomography (SS-OCT) and Placido disk topography in eyes with cataracts. Seventy-eight eyes from seventy-eight patients with cataracts were evaluated. Axial length (AL), anterior chamber depth (ACD), keratometry (K) over a 2.5 mm and 3.0 mm diameter, lens thickness (LT), central corneal thickness (CCT) and white-to-white (WTW) distance were measured by 2 skilled operators. OA-2000 measurements were highly repeatable and reproducible for all parameters (intraclass correlation, 0.925 to 1.000). OA-2000 derived K-values with ...

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    16. Visualization and quantification of injury to the ciliated epithelium using quantitative flow imaging and speckle variance optical coherence tomography

      Visualization and quantification of injury to the ciliated epithelium using quantitative flow imaging and speckle variance optical coherence tomography

      Mucociliary flow is an important defense mechanism in the lung to remove inhaled pathogens and pollutants. Disruption of ciliary flow can lead to respiratory infections. Multiple factors, from drugs to disease can cause an alteration in ciliary flow. However, less attention has been given to injury of the ciliated epithelium. In this study, we show how optical coherence tomography (OCT) can be used to investigate injury to the ciliated epithelium in a multi-contrast setting. We used particle tracking velocimetry (PTV-OCT) to investigate the cilia-driven flow field and 3D speckle variance imaging to investigate size and extent of injury caused to ...

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    17. OCT Amplitude and Speckle Statistics of Discrete Random Media

      OCT Amplitude and Speckle Statistics of Discrete Random Media

      Speckle, amplitude fluctuations in optical coherence tomography (OCT) images, contains information on sub-resolution structural properties of the imaged sample. Speckle statistics could therefore be utilized in the characterization of biological tissues. However, a rigorous theoretical framework relating OCT speckle statistics to structural tissue properties has yet to be developed. As a first step, we present a theoretical description of OCT speckle, relating the OCT amplitude variance to size and organization for samples of discrete random media (DRM). Starting the calculations from the size and organization of the scattering particles, we analytically find expressions for the OCT amplitude mean, amplitude variance ...

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    18. Intravascular Optical Coherence Tomography for Characterization of Atherosclerosis with a 1.7 Micron Swept-Source Laser

      Intravascular Optical Coherence Tomography for Characterization of Atherosclerosis with a 1.7 Micron Swept-Source Laser

      The main cause of acute coronary events, such as thrombosis, is the rupture of atherosclerotic plaques. Typical intravascular optical coherence tomography (IVOCT) imaging systems that utilize a 1.3 μm swept source laser are often used for identifying fibrous cap thickness of plaques, yet cannot provide adequate depth penetration to resolve the size of the lipid pool. Here, we present a novel IVOCT system with a 1.7 μm center wavelength swept light source that can readily penetrate deeper into the tissue because of the longer wavelength and allows for better identification of plaques due to the lipid absorption spectrum ...

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    19. A novel and faster method of manual grading to measure choroidal thickness using optical coherence tomography

      A novel and faster method of manual grading to measure choroidal thickness using optical coherence tomography

      Purpose Choroidal thickness (CT) measurements are typically obtained from manual segmentation of optical coherence tomography (OCT) B-scans. This method is time-consuming. We aimed to describe a novel and faster technique to obtain CT measurements. Patients and methods In a prospective cohort study of 200 healthy eyes, Spectral-Domain OCT with enhanced depth imaging were performed with the Spectralis OCT using standardised imaging protocols. The OCT scans were independently graded by reading centre-certified graders. The standard method of manual adjustment of segmentation boundaries was performed. The new method consisted of adjusting the lower segmentation line to the choroid-scleral boundary to generate the ...

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    20. Visualizing Micro-anatomical Structures of the Posterior Cornea with Micro-optical Coherence Tomography

      Visualizing Micro-anatomical Structures of the Posterior Cornea with Micro-optical Coherence Tomography

      Diagnosis of corneal disease and challenges in corneal transplantation require comprehensive understanding of corneal anatomy, particularly that of the posterior cornea. Micro-optical coherence tomography (µOCT) is a potentially suitable tool to meet this need, owing to its ultrahigh isotropic spatial resolution, high image acquisition rate and depth priority scanning mode. In this study, we explored the ability of µOCT to visualize micro-anatomical structures of the posterior cornea ex vivo and in vivo using small and large animals. µOCT clearly delineated cornea layers and revealed micro-anatomical structures, including not only polygonal endothelial cells, stellate keratocytes, collagen fibres and corneal nerve fibres ...

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    21. Combination of optical coherence tomography and near infrared spectroscopy enhances determination of articular cartilage composition and structure

      Combination of optical coherence tomography and near infrared spectroscopy enhances determination of articular cartilage composition and structure

      Conventional arthroscopic evaluation of articular cartilage is subjective and poorly reproducible. Therefore, implementation of quantitative diagnostic techniques, such as near infrared spectroscopy (NIRS) and optical coherence tomography (OCT), is essential. Locations ( n  = 44) with various cartilage conditions were selected from mature equine fetlock joints ( n  = 5). These locations and their surroundings were measured with NIRS and OCT ( n  = 530). As a reference, cartilage proteoglycan (PG) and collagen contents, and collagen network organization were determined using quantitative microscopy. Additionally, lesion severity visualized in OCT images was graded with an automatic algorithm according to International Cartilage Research Society (ICRS) scoring system. Artificial ...

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    22. An overview of the clinical applications of optical coherence tomography angiography

      An overview of the clinical applications of optical coherence tomography angiography

      Optical coherence tomography angiography (OCTA) has emerged as a novel, non-invasive imaging modality that allows the detailed study of flow within the vascular structures of the eye. Compared to conventional dye angiography, OCTA can produce more detailed, higher resolution images of the vasculature without the added risk of dye injection. In our review, we discuss the advantages and disadvantages of this new technology in comparison to conventional dye angiography. We provide an overview of the current OCTA technology available, compare the various commercial OCTA machines technical specifications and discuss some future software improvements. An approach to the interpretation of OCTA ...

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    23. Visualization and Detection of Ciliary Beating Pattern and Frequency in the Upper Airway using Phase Resolved Doppler Optical Coherence Tomography

      Visualization and Detection of Ciliary Beating Pattern and Frequency in the Upper Airway using Phase Resolved Doppler Optical Coherence Tomography

      Ciliary motion plays a critical role in the overall respiratory health of the upper airway. These cilia beat at a native frequency and in a synchronized pattern to continuously transport foreign particulate trapped in a layer of mucous out of the upper airway. Disruption of ciliary motion can lead to severe respiratory diseases and compromised respiratory function. Currently, the study of cilia requires expensive high speed cameras and high powered microscopes which is unsuitable for in vivo imaging and diagnosis. Doppler based optical coherence tomography has the potential to visualize the microscopic motion of cilia during their beating cycle. We ...

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    24. In vivo assessment of macula in eyes of healthy children 8 to 16 years old using optical coherence tomography angiography

      In vivo assessment of macula in eyes of healthy children 8 to 16 years old using optical coherence tomography angiography

      The purpose of the present study was to investigate the vascular flow density (VD) of macular superficial (SCP), deep capillary plexus (DCP), and choriocapillaris and the size of the foveal avascular zone (FAZ) area in healthy children using optical coherence tomography angiography (OCTA). The potential associations of age, sex, intraocular pressure, body mass index, spherical equivalent, and axial length with OCTA parameters were also investigated. A total of 75 eyes from 75 healthy children were included for analysis, with the mean age 11.51 ± 1.91 years (range, 8–16 years). At the level of the SCP, mean VD and ...

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