1. 1-24 of 452 1 2 3 4 ... 17 18 19 »
    1. Relationship of ocular and systemic factors to the visibility of choroidal–scleral interface using spectral domain optical coherence tomography

      Relationship of ocular and systemic factors to the visibility of choroidal–scleral interface using spectral domain optical coherence tomography

      Purpose To assess the visibility of the choroidal–scleral interface (CSI) from spectral domain optical coherence tomography (SD-OCT) and evaluate the ocular and systemic factors influencing the visibility of CSI in healthy eyes from population-based Malay sample. Methods Participants were consecutively recruited from the population-based Singapore Malay Eye Study-2 (SiMES-2). SD-OCT images were obtained by Spectralis OCT with enhanced depth imaging (EDI) mode. Visibility of CSI was assessed by a grading system ranging from 0 to 2 scores. The reliability of choroidal thickness measurement in different grades of CSI visibility was assessed using intraclass correlation coefficient. Ordinal regression analyses were ...

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    2. Effects of rigid contact lenses on optical coherence tomographic parameters in eyes with keratoconus

      Effects of rigid contact lenses on optical coherence tomographic parameters in eyes with keratoconus

      Background The aim was to evaluate the effect of irregular astigmatism on the retinal nerve fibre layer (RNFL), macular thickness and ganglion cell analysis obtained by spectral domain optical coherence tomography (OCT) in eyes with keratoconus. Methods Fifty-two eyes of 31 patients (20 females) with keratoconus that required correction of irregular astigmatism with rigid gas-permeable (RGP) contact lenses were included to this study. The average, superior, nasal, inferior, temporal and 12 clock hour sector's RNFL, ganglion cell and macular thickness analyses before and 30 minutes after RGP contact lens (Rose K2 -Menicon Z material, David Thomas Contact Lenses Ltd ...

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    3. Rapid fabrication system for three-dimensional tissues using cell sheet engineering and centrifugation

      Rapid fabrication system for three-dimensional tissues using cell sheet engineering and centrifugation

      Three-dimensional (3-D) tissues can be reconstructed by cell sheet technology, and various clinical researches using these constructed tissues have already been initiated to regenerate damaged tissues. While 3-D tissues can be easily fabricated by layering cell sheets, the attachment period for cell adhesion between a cell sheet and a culture dish, or double-layered cell sheets normally takes 20-30 min. This study proposed a more rapid fabrication system for bioengineered tissue using cell sheet technology and centrifugation. A C2C12 mouse myoblast sheet harvested from a temperature-responsive culture dish will attach tightly to a culture dish or another cell sheet at 37 ...

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    4. Imaging of subchondral bone by optical coherence tomography upon optical clearing of articular cartilage

      Imaging of subchondral bone by optical coherence tomography upon optical clearing of articular cartilage

      Optical clearing is an effective method to reduce light scattering of biological tissues that provides significant enhancement of light penetration into the biological tissues making non-invasive diagnosis more feasible. In current report Optical Coherence Tomography (OCT) in conjunction with optical clearing is applied for assessment of deep cartilage layers and cartilage-bone interface. The solution of Iohexol in water has been used as an optical clearing agent. The cartilage-bone boundary becomes visible after 15 min of optical clearing that enabling non-invasive estimation of its roughness: S a = 10 ± 1 µm. The results show that for 0.9 mm thick cartilage optical ...

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    5. Detection of retinal changes in idiopathic Parkinson's disease using high-resolution optical coherence tomography and heidelberg retina tomography

      Detection of retinal changes in idiopathic Parkinson's disease using high-resolution optical coherence tomography and heidelberg retina tomography

      Purpose The study was performed to analyse the retina of patients with Parkinson's disease (PD) for morphological changes compared to healthy controls (HC) using spectral-domain optical coherence tomography (SD-OCT) and confocal scanning laser ophthalmoscopy. Methods We enrolled 108 patients with idiopathic PD and 165 HC. All study participants underwent an ophthalmological examination to exclude ophthalmological disorder potentially interfering with the retinal analyses. Peripapillary retinal nerve fibre layer (RNFL) thickness and macular thickness and volume were measured by a SD-OCT device (Heidelberg Spectralis ® ). Stereometric parameters of the optic disc were acquired by Heidelberg Retina Tomograph (HRT III). Results The RNFL ...

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    6. Scanning laser polarimetry and spectral domain optical coherence tomography for the detection of retinal changes in Parkinson's disease

      Scanning laser polarimetry and spectral domain optical coherence tomography for the detection of retinal changes in Parkinson's disease

      Purpose Whether retinal degeneration is part of the degenerative processes in patients with Parkinson's disease (PD) is still unclear. This cross-sectional study was undertaken to compare the retinal morphology of patients with PD and healthy controls using spectral domain optical coherence tomography (SD-OCT) and scanning laser polarimetry (SLP). Methods Both eyes of patients with PD ( n = 108) and healthy controls ( n = 165) were examined using SD-OCT and SLP on the same day. Data on the thickness of the retinal nerve fibre layer (RNFL) of all quadrants and the macular area were acquired by OCT (Cirrus, Zeiss). The SLP device ...

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    7. Skin substitute-assisted repair shows reduced dermal fibrosis in acute human wounds validated simultaneously by histology and optical coherence tomography

      Skin substitute-assisted repair shows reduced dermal fibrosis in acute human wounds validated simultaneously by histology and optical coherence tomography

      Skin substitutes are heterogeneous biomaterials designed to accelerate wound healing through provision of replacement extracellular matrix. Despite growing evidence for their use in chronic wounds, the role of skin substitutes in acute wound management and their influence upon fibrogenesis remains unclear. Skin substitute characteristics including biocompatibility, porosity and elasticity strongly influence cellular behaviour during wound healing. Thus, we hypothesise that structural and biomechanical variation between biomaterials may induce differential scar formation after cutaneous injury. The following human prospective cohort study was designed to investigate this premise. Four 5mm full-thickness punch biopsies were harvested from fifty volunteers. In all cases, site ...

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    8. In-Line Monitoring of a Pharmaceutical Pan Coating Process by Optical Coherence Tomography

      In-Line Monitoring of a Pharmaceutical Pan Coating Process by Optical Coherence Tomography

      This work demonstrates a new in-line measurement technique for monitoring the coating growth of randomly moving tablets in a pan coating process. In-line quality control is performed by an optical coherence tomography (OCT) sensor allowing nondestructive and contact-free acquisition of cross-section images of film coatings in real time. The coating thickness can be determined directly from these OCT images and no chemometric calibration models are required for quantification. Coating thickness measurements are extracted from the images by a fully automated algorithm. Results of the in-line measurements are validated using off-line OCT images, thickness calculations from tablet dimension measurements, and weight ...

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    9. Backscattering intensity measurements in optical coherence tomography as a method to identify parathyroid glands

      Backscattering intensity measurements in optical coherence tomography as a method to identify parathyroid glands

      Background and Objective Previous studies have shown that the use of optical coherence tomography (OCT) permits the differentiation between parathyroid tissue, thyroid tissue, lymph nodes and adipose tissue. We investigated the backscattering intensity profiles of OCT images in order to determine whether significant differences between these tissue types exist. Methods Mean backscattering intensity profiles were obtained from OCT images of parathyroid glands, thyroid tissue, lymph nodes and adipose tissue. The profiles were analyzed employing Fisher's Linear Discriminant Analysis (LDA). The results were cross validated employing improved parameter estimation techniques. Results Mean backscattering intensity profiles from 300 OCT images of ...

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      Mentions: Julia Gallwas
    10. A 12–month angiographic and optical coherence tomography follow-up after bioresorbable vascular scaffold implantation in patients with ST-segment elevation myocardial infarction

      A 12–month angiographic and optical coherence tomography follow-up after bioresorbable vascular scaffold implantation in patients with ST-segment elevation myocardial infarction

      Objectives The aim of the study was to evaluate the healing process at 12 months after ABSORB™ bioresorbable vascular scaffold (BVS) implantation in patients with ST-segment elevation myocardial infarction (STEMI). Background There is currently no data on long-term BVS performance in the acute thrombotic setting. The underlying altered plaque pathomorphology may impact the neointima healing pattern, potentially making it different to that observed in stable coronary artery disease (CAD). Methods We have performed an angiographic and optical coherence tomography (OCT) 12-month follow-up of 19 STEMI patients who were treated with a BVS implantation (23 scaffolds). An independent core laboratory performed ...

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    11. Detection of plaque structure and composition using OCT combined with two-photon luminescence (TPL) imaging

      Detection of plaque structure and composition using OCT combined with two-photon luminescence (TPL) imaging

      Background and Objectives Atherosclerosis and plaque rupture leads to myocardial infarction and stroke. A novel hybrid optical coherence tomography (OCT) and two-photon luminescence (TPL) fiber-based imaging system was developed to characterize tissue constituents in the context of plaque morphology. Study Design/Materials and Methods Ex vivo coronary arteries (34 regions of interest) from three human hearts with atherosclerotic plaques were examined by OCT–TPL imaging. Histological sections (4 μm in thickness) were stained with Oil Red O for lipid, Von Kossa for calcium, and Verhoeff–Masson Tri-Elastic for collagen/elastin fibers and compared with imaging results. Results Biochemical components in ...

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    12. Novel digital imaging techniques to assess the outcome in oral rehabilitation with dental implants: a narrative review

      Novel digital imaging techniques to assess the outcome in oral rehabilitation with dental implants: a narrative review

      Aim To examine the literature on novel digital imaging techniques for the assessment of outcomes in oral rehabilitation with dental implants. Material and methods An electronic search of Medline and Embase databases including studies published prior to 28th December 2014 was performed and supplemented by a manual search. A synthesis of the publications was presented describing the use of computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography, optical scanning, spectrophotometry or optical coherence tomography (OCT) related to the outcome measures in implant therapy. Results and conclusions Most of the digital imaging techniques have not yet sufficiently been validated to be ...

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    13. A 12-month angiographic and optical coherence tomography follow-up after bioresorbable vascular scaffold implantation in patients with ST-segment elevation myocardial infarction

      A 12-month angiographic and optical coherence tomography follow-up after bioresorbable vascular scaffold implantation in patients with ST-segment elevation myocardial infarction

       Objectives The aim of the study was to evaluate the healing process at 12 months after ABSORB™ bioresorbable vascular scaffold (BVS) implantation in patients with ST-segment elevation myocardial infarction (STEMI). Background There is currently no data on long-term BVS performance in the acute thrombotic setting. The underlying altered plaque pathomorphology may impact the neointima healing pattern, potentially making it different to that observed in stable coronary artery disease (CAD). Methods We have performed an angiographic and optical coherence tomography (OCT) 12-month follow-up of 19 STEMI patients who were treated with a BVS implantation (23 scaffolds). An independent core laboratory performed ...

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    14. Optical coherence tomography assessment of the mechanistic effects of rotational and orbital atherectomy in severely calcified coronary lesions

      Optical coherence tomography assessment of the mechanistic effects of rotational and orbital atherectomy in severely calcified coronary lesions

      Objectives This study sought to assess the mechanistic effect of rotational atherectomy (RA) and orbital atherectomy (OA) on heavily calcified coronary lesions and subsequent stent placement using optical coherence tomography (OCT). Background RA and OA are two main approaches to ablate coronary calcium. While small case reports have described the mechanistic effect of RA in calcified coronary lesions, there has been no imaging study to assess the effect of OA on coronary artery architecture and/or compare the effects of two atherectomy devices. Methods This study analyzed 20 consecutive patients with OCT imaging performed after atherectomy and after stent implantation ...

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    15. Computer-aided analyses of mouse retinal OCT images – an actual application report

      Computer-aided analyses of mouse retinal OCT images – an actual application report

      Purpose There is a need for automated retinal optical coherence tomography (OCT) image analysis tools for quantitative measurements in small animals. Some image processing techniques for retinal layer analysis have been developed, but reports about how useful those techniques are in actual animal studies are rare. This paper presents the use of a retinal layer detection method we developed in an actual mouse study that involves wild type and mutated mice carrying photoreceptor degeneration. Methods Spectral domain OCT scanning was performed by four experimenters over 12 months on 45 mouse eyes that were wild-type, deficient for ephrin-A2 and ephrin-A3, deficient ...

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    16. Volumetric laser endomicroscopy in Barrett's esophagus: a feasibility study on histological correlation

      Volumetric laser endomicroscopy in Barrett's esophagus: a feasibility study on histological correlation

      Volumetric laser endomicroscopy (VLE) is a novel balloon-based optical coherence tomography (OCT) imaging technique that may improve detection of early neoplasia in Barrett's esophagus (BE). Most OCT studies lack a direct correlation between histology and OCT images. The aim is to investigate the optimal approach for achieving one-to-one correlation of ex-vivo VLE images of endoscopic resection (ER) specimens with histology. BE patients with and without early neoplasia underwent ER after delineating areas with electrocoagulation markers (ECM). After ER, specimens underwent additional ex-vivo marking with several different markers (ink, pin, Gold Probe) followed by ex-vivo VLE scanning. ER specimens were ...

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    17. Closed loop tracked Doppler optical coherence tomography based heart monitor for the Drosophila melanogaster larvae

      Closed loop tracked Doppler optical coherence tomography based heart monitor for the Drosophila melanogaster larvae

      A fruit fly larva (top) was continuously tracked for continuous remote monitoring. A heartbeat trace of freely moving larva (bottom) was obtained by a low coherence interferometry based doppler sensing technique. This paper presents a novel instrument for biosciences, useful for studies of moving embryos. A dual sequential imaging/measurement channel is assembled via a closed-loop tracking architecture. The dual channel system can operate in two regimes: (i) single-point Doppler signal monitoring or (ii) fast 3-D swept source OCT imaging. The system is demonstrated for characterizing cardiac dynamics in Drosophila melanogaster larva. Closed loop tracking enables long term in vivo ...

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    18. On the horizon: Optical imaging for cutaneous squamous cell carcinoma

      On the horizon: Optical imaging for cutaneous squamous cell carcinoma

      Background : Surgical resection with negative margins remains the standard of care for high-risk cutaneous squamous cell carcinoma (cSCC). However, surgical management is often limited by poor intraoperative tumor visualization and inability to detect occult nodal metastasis. The inability to intraoperatively detect microscopic disease can lead to additional surgery, tumor recurrence, and decreased survival. Methods : A comprehensive literature review was conducted to identify studies incorporating optical imaging technology in the management of cSCC (1/1/2000-11/1/2014). Results : Several innovative optical imaging techniques, Raman spectroscopy, confocal microscopy, and fluorescence imaging, have been developed for intraoperative surgical guidance. Fifty-seven studies review ...

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    19. The sensitivity and specificity of optical coherence tomography for the assisted diagnosis of non-pigmented basal cell carcinoma - an observational study

      The sensitivity and specificity of optical coherence tomography for the assisted diagnosis of non-pigmented basal cell carcinoma - an observational study

      Background The diagnostic criteria for basal cell carcinoma (BCC) using optical coherence tomography (OCT) have been described previously, but the clinical value of these findings has been unknown. Objective The aim of this study was to investigate the diagnostic value of OCT for BCC in a typical clinical setting. The primary efficacy endpoint was a diagnosis of BCC for each lesion. Secondary endpoints were the diagnosis of other possible conditions. Methods This was an observational, prospective, multi-centre study in which consecutive patients with non-pigmented pink lesions suspicious for BCC underwent clinical assessment, dermoscopy, and OCT with the diagnosis recorded at ...

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    20. Collateral damage to the ureter and Nitinol stone baskets during thulium fiber laser lithotripsy

      Collateral damage to the ureter and Nitinol stone baskets during thulium fiber laser lithotripsy

      Background The experimental Thulium fiber laser (TFL) is currently being studied as a potential alternative lithotripter to the clinical gold standard Holmium:YAG laser. Safety studies characterizing undesirable Holmium:YAG laser-induced damage to ureter tissue and stone baskets have been previously reported. Similarly, this study characterizes TFL induced ureter and stone basket damage. Methods A TFL beam with energy of 35 mJ per pulse, pulse duration of 500 µs, and variable pulse rates of 50–500 Hz, was delivered through 100-µm-core optical fibers, to either porcine ureter wall, in vitro , or a standard 1.9-Fr Nitinol stone basket wire ...

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    21. Dimensional metrology of lab-on-a-chip internal structures: a comparison of optical coherence tomography with confocal fluorescence microscopy

      Dimensional metrology of lab-on-a-chip internal structures: a comparison of optical coherence tomography with confocal fluorescence microscopy

      Summary The characterization of internal structures in a polymeric microfluidic device, especially of a final product, will require a different set of optical metrology tools than those traditionally used for microelectronic devices. We demonstrate that optical coherence tomography (OCT) imaging is a promising technique to characterize the internal structures of poly(methyl methacrylate) devices where the subsurface structures often cannot be imaged by conventional wide field optical microscopy. The structural details of channels in the devices were imaged with OCT and analyzed with an in-house written ImageJ macro in an effort to identify the structural details of the channel. The ...

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