1. 721-744 of 765 « 1 2 ... 28 29 30 31 32 »
    1. Optical molecular imaging of atherosclerosis using nanoparticles: shedding new light on the darkness

      Optical molecular imaging of atherosclerosis using nanoparticles: shedding new light on the darkness
      The application of optical nanoparticles in cardiovascular research is increasing because of the high spatiotemporal resolution and high sensitivity of optical techniques as compared with other imaging platforms. The major cause of cardiovascular events is atherosclerosis, which is a chronic inflammation of the arterial wall. Interestingly, the composition rather than the size of nonstenotic atherosclerotic plaques and severe plaques with >90% stenosis are indicators for high-risk vulnerability to rupture and acute cardiovascular events. Optical techniques may be highly suitable for discriminating, at subcellular resolution, the different stages of plaque progression by targeting bright and nontoxic optical nanoparticles toward distinct molecular ...
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    2. Rationale and design of the randomized, multicenter EREMUS trial, a study that investigates how to achieve low restenosis and early reendothelialization after percutaneous coronary interventions

      Rationale and design of the randomized, multicenter EREMUS trial, a study that investigates how to achieve low restenosis and early reendothelialization after percutaneous coronary interventions
      Background: Drug eluting stent (DES) use has improved clinical outcome after percutaneous coronary interventions. However, DES-treated patients may have a higher risk of stent thrombosis, mainly due to uncorrect stent deployment or lack of reendothelialization. Thus, the availabilily of different approaches with comparable efficacy to DES, but higher safety, especially in bleeding-prone patients, have to be investigated. Study Design: The EREMUS is a multicenter open-label prospective randomized three-arm clinical trial that will investigate the efficacy of a paclitaxel coated balloon + an endothelial progenitor capture stent for the treatment of native coronary lesions, and compare it to a DES strategy, or ...
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    3. RNFL thickness in MS-associated acute optic neuritis using SD-OCT: critical interpretation and limitations

      RNFL thickness in MS-associated acute optic neuritis using SD-OCT: critical interpretation and limitations
      Purpose:  Axonal loss is considered a key prognostic factor in diagnosing and monitoring the progress of multiple sclerosis (MS). The purpose of our research was to determine whether the measurement of retinal nerve fibre layer thickness (RNFLT) as measured with high-resolution spectral-domain optical coherence tomography (SD-OCT) differs between optic nerve injury following acute optic neuritis (ON) or following unregistered subclinical axonal damage in patients with MS.Methods:  High-resolution SD-OCT measurements of RNFLT were initially carried out in the acute phase of ON and again after 3 months, in 25 patients with clinical definite MS and 25 sex- and age-matched healthy ...
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    4. Automatic measurement of epidermal thickness from optical coherence tomography images using a new algorithm

      Automatic measurement of epidermal thickness from optical coherence tomography images using a new algorithm
      Background/purpose: Optical coherence tomography (OCT) is an imaging system that enables in vivo epidermal thickness (ET) measurement. In order to use OCT in large-scale clinical studies, automatic algorithm detection of the dermo-epidermal junction (DEJ) is needed. This may be difficult due to image noise from optical speckle, which requires specific image treatment procedures to reduce this. In the present work, a description of the position of the DEJ is given, and an algorithm for boundary detection is presented. Methods: Twenty-nine images were taken from the skin of normal healthy subjects, from five different body sites. Seven expert assessors were ...
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    5. Is quantitative spectral-domain superior to time-domain optical coherence tomography (OCT) in eyes with age-related macular degeneration?

      Is quantitative spectral-domain superior to time-domain optical coherence tomography (OCT) in eyes with age-related macular degeneration?
      Purpose:  The aim of this study was to determine the variability of macular map measurements, for two generations of optical coherence tomography (OCT) instruments, in eyes with wet age related macular degeneration (AMD) and low visual acuity. Methods:  Patients were examined with Stratus OCT and Cirrus HD-OCT. The macular thickness was assessed with the ‘macular thickness map scan’ and ‘fast protocol’ in Stratus and with the 512 × 128 and 200 × 200 cube protocols in Cirrus OCT. Two measurements were taken one directly after the other, at the first visit to analyse repeatability. Approximately 1 week later, a third measurement was ...
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    6. A clinical instrument for combined raman spectroscopy-optical coherence tomography of skin cancers

      A clinical instrument for combined raman spectroscopy-optical coherence tomography of skin cancers

      Background and Objective The current standard for diagnosis of skin cancers is visual inspection followed by biopsy and histopathology. This process can be invasive, subjective, time consuming, and costly. Optical techniques, including Optical Coherence Tomography (OCT) and Raman Spectroscopy (RS), have been developed to perform non-invasive characterization of skin lesions based on either morphological or biochemical features of disease. The objective of this work is to report a clinical instrument capable of both morphological and biochemical characterization of skin cancers with RS-OCT. Materials and Methods The portable instrument utilizes independent 785 nm RS and 1,310 nm OCT system backbones ...

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    7. Ranibizumab in the treatment of choroidal neovascularisation due to age-related macular degeneration: an optical coherence tomography and multifocal electroretinography study

      Ranibizumab in the treatment of choroidal neovascularisation due to age-related macular degeneration: an optical coherence tomography and multifocal electroretinography study
      Background:  The aim of this study was to evaluate, by optical coherence tomography (OCT) and multifocal electroretinography (mfERG), the macular function of eyes with choroidal neovascularisation due to age-related macular degeneration (AMD) before and after the intravitreal use of ranibizumab. Methods:  Fifteen eyes with choroidal neovascularisation due to AMD were studied with OCT and mfERG before, during and at the end of the treatment, one year after the first injection of ranibizumab. The eyes received 0.5 mg ranibizumab every month for the first three months, followed by doses every three months. Thus, during the 12-month study, a total of ...
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    8. Optical coherence tomography for the diagnosis of cervical intraepithelial neoplasia

      Optical coherence tomography for the diagnosis of cervical intraepithelial neoplasia
      Background and Objectives Optical coherence tomography (OCT) permits high-resolution imaging of tissue subsurfaces up to 2 mm in depth. The purpose of this study was to evaluate the accuracy and reproducibility of OCT in the characterization of cervical intraepithelial neoplasia (CIN) and to distinguish between different CIN grades. Study Design/Materials and Methods Colposcopy-guided OCT images were taken from unsuspicious and suspicious areas in women with suspected CIN. Each woman then underwent directed biopsies. All OCT images were separately evaluated by two blinded investigators and later compared to the corresponding histology based on a 6-grade classification (normal, inflammation, CIN 1 ...
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    9. State of the art in non-invasive imaging of cutaneous melanoma

      State of the art in non-invasive imaging of cutaneous melanoma
      Background: This review focuses on looking at recent developments in the non-invasive imaging of skin, in particular at how such imaging may be used at present or in the future to detect cutaneous melanoma. Methods: A MEDLINE search was performed for papers using imaging techniques to evaluate cutaneous melanoma, including melanoma metastasis. Results: Nine different techniques were found: dermoscopy, confocal laser scanning microscopy (including multiphoton microscopy), optical coherence tomography, high frequency ultrasound, positron emission tomography, magnetic resonance imaging, and Fourier, Raman, and photoacoustic spectroscopies. This review contrasts the effectiveness of these techniques when seeking to image melanomas in skin. Conclusions ...
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    10. In vivo response of GsdmA3Dfl/+ mice to topically applied anti-psoriatic agents: effects on epidermal thickness, as determined by optical coherence tomography and H&E staining.

      In vivo response of GsdmA3Dfl/+ mice to topically applied anti-psoriatic agents: effects on epidermal thickness, as determined by optical coherence tomography and H&E staining.

      This study evaluated in vivo the potential of optical coherence tomography (OCT) to determine changes in thickness of the epidermis in response to the topically applied anti-psoriatics betamethasone dipropionate (BD), salicylic acid (SA) and also fish oil (FO). GsdmA3Dfl/+ mice have an inflammatory hair loss phenotype that includes hyperproliferation and epidermal thickening, hence a potential psoriasis model. Changes in epidermal thickness were evaluated over a period of 10 days, with the mice treated with combined BD + SA, FO + SA and BD + FO + SA. The data were validated with conventional measurement using H&E staining coupled with microscopy. Initial baseline measurement ...

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    11. Drusen detection in retro-mode imaging by a scanning laser ophthalmoscope

      Drusen detection in retro-mode imaging by a scanning laser ophthalmoscope
      Purpose:  The Nidek F-10 is a scanning laser ophthalmoscope that is capable of a novel fundus imaging technique, so-called ‘retro-mode’ imaging. The standard method of imaging drusen in age-related macular degeneration (AMD) is by fundus photography. The aim of the study was to assess drusen quantification using retro-mode imaging. Methods:  Stereoscopic fundus photographs and retro-mode images were captured in 31 eyes of 20 patients with varying stages of AMD. Two experienced masked retinal graders independently assessed images for the number and size of drusen, using purpose-designed software. Drusen were further assessed in a subset of eight patients using optical coherence ...
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    12. In Vivo Comparison of the Optical Clearing Efficacy of Optical Clearing Agents in Human Skin by Quantifying Permeability Using Optical Coherence Tomography

      In Vivo Comparison of the Optical Clearing Efficacy of Optical Clearing Agents in Human Skin by Quantifying Permeability Using Optical Coherence Tomography

      The objective of the present work is to quantify and compare the optical clearing efficacy of glucose, propylene glycol, glycerol solutions through the human skin tissue in vivo by calculating permeability coefficient of three solutions. Currently, the permeability coefficient of agent in tissues was extracted from OCT amplitude data mainly through the OCT signal slope (OCTSS) and the OCT amplitude (OCTA) methods. In this study, we report the OCT attenuation coefficient (OCTAC) method which is relatively novel and rarely reported methodology to measure the permeability coefficient during the optical skin clearing procedure. The permeability coefficients for 40% propylene glycol, glucose ...

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    13. Optically based-indentation technique for acute rat brain tissue slices and thin biomaterials

      Optically based-indentation technique for acute rat brain tissue slices and thin biomaterials
      Currently, micro-indentation testing of soft biological materials is limited in its capability to test over long time scales due to accumulated instrumental drift errors. As a result, there is a paucity of measures for mechanical properties such as the equilibrium modulus. In this study, indentation combined with optical coherence tomography (OCT) was used for mechanical testing of thin tissue slices. OCT was used to measure the surface deformation profiles after placing spherical beads onto submerged test samples. Agarose-based hydrogels at low-concentrations (w/v, 0.3–0.6%) and acute rat brain tissue slices were tested using this technique over a ...
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    14. Impact of Preprocedural High-Sensitivity C-Reactive Protein Levels on Uncovered Stent Struts: An Optical Coherence Tomography Study After Drug-Eluting Stent Implantation

      Impact of Preprocedural High-Sensitivity C-Reactive Protein Levels on Uncovered Stent Struts: An Optical Coherence Tomography Study After Drug-Eluting Stent Implantation

      BackgroundThere are no sufficient data to evaluate the relationship between high-sensitivity C-reactive protein (hs-CRP) and uncovered stent struts on optical coherence tomography (OCT) after drug-eluting stent (DES) implantation.HypothesisWe evaluated the relationship between the preprocedural level of hs-CRP and incomplete neointimal coverage of DES struts on OCT.MethodsThis study was conducted using 124 eligible patients (132 lesions) treated with sirolimus-eluting stents (SES) or zotarolimus-eluting stents (ZES). The subjects were divided into 2 groups based on the preprocedural hs-CRP level: high-CRP (≥3 mg/L; 58 lesions) and normal-CRP (

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    15. Transverse flow velocity quantification using optical coherence tomography with correlation

      Transverse flow velocity quantification using optical coherence tomography with correlation
      We describe a method that uses classic optical coherence tomography to measure the transverse fluid-flow velocity quantitatively without knowing the Doppler angle. An intensity based cross-correlation calculation is taken point-to-pointly between two close cross sections of the scattering fluid to estimate the time delay for scattering particles passing through the two sections which are scanned alternately. The transverse velocity distribution of the scattering fluid-flow in the whole section is achieved finally. The experimental results agree well with the preset ones. This method is insensitive to the Doppler angle and provides a variable velocity detection range in different application conditions.
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    16. Speckle variance OCT imaging of the vasculature in live mammalian embryos

      Speckle variance OCT imaging of the vasculature in live mammalian embryos

      Live imaging of normal and abnormal vascular development in mammalian embryos is important tool in embryonic research, which can potentially contribute to understanding, prevention and treatment of cardiovascular birth defects. Here, we used speckle variance analysis of swept source optical coherence tomography (OCT) data sets acquired from live mouse embryos to reconstruct the 3-D structure of the embryonic vasculature. Both Doppler OCT and speckle variance algorithms were used to reconstruct the vascular structure. The results demonstrates that speckle variance imaging provides more accurate representation of the vascular structure, as it is not sensitive to the blood flow direction, while the ...

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    17. Hair shaft abnormalities in alopecia areata evaluated by optical coherence tomography

      Hair shaft abnormalities in alopecia areata evaluated by optical coherence tomography

      Background/purpose: Optical coherence tomography (OCT) is able to provide highly reproducible measurements of hair shaft thickness, including hair shaft diameter, cross-sectional surface area and hair shape, similar to histology but in vivo. Variations in the caliber of hair shafts have been described in patchy hair loss like alopecia areata (AA) using electron microscopy. The aim of this study was to evaluate whether OCT is useful for the evaluation of hair shaft abnormalities in AA. Methods: The measurements were performed on patients with AA (n=9), aged 2–66 years. Fifty hairs from the border of an alopecic area and ...

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      Mentions: Jürgen Lademann
    18. Artefact reduction for cell migration visualization using spectral domain optical coherence tomography

      Artefact reduction for cell migration visualization using spectral domain optical coherence tomography
      Visualization of cell migration during chemotaxis using spectral domain optical coherence tomography (OCT) requires non-standard processing techniques. Stripe artefacts and camera noise floor present in OCT data prevent detailed computer-assisted reconstruction and quantification of cell locomotion. Furthermore, imaging artefacts lead to unreliable results in automated texture based cell analysis. Here we characterize three pronounced artefacts that become visible when imaging sample structures with high dynamic range, e.g. cultured cells: (i) time-varying fixed-pattern noise; (ii) stripe artefacts generated by background estimation using tomogram averaging; (iii) image modulations due to spectral shaping. We evaluate techniques to minimize the above mentioned artefacts ...
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    19. Optical Coherence Tomography: A New Imaging Modality for Plaque Characterization and Stent Implantation

      Optical Coherence Tomography: A New Imaging Modality for Plaque Characterization and Stent Implantation

      Optical coherence tomography (OCT) is a novel, catheter-based, invasive imaging system based on near-infrared light with high image resolution (15–20 μm). The system allows for unparalleled imaging of the coronary artery lumen, plaque characterization, assessment of coronary stent strut apposition, neointimal coverage, vascular proliferative response, complications such as focal dissection or thrombus formation, and insight into the time course of stent endothelization. This review will describe the currently available developments in OCT technology and its application in both the clinical and research arenas.

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    20. Correlation mapping method for generating microcirculation morphology from optical coherence tomography (OCT) intensity images

      Correlation mapping method for generating microcirculation morphology from optical coherence tomography (OCT) intensity images
      Standard optical coherence tomography (OCT) in combination with software tools can be harnessed to generate vascular maps in vivo. In this study we have successfully combined a software algorithm based on correlation statistic to reveal microcirculation morphology on OCT intensity images of a mouse brain in vivo captured trans-cranially and through a cranial window. We were able to estimate vessel geometry at bifurcation as well as along vessel segments down-to mean diameters of about 24 μm. Our technique has potential applications in cardiovascular-related parameter measurements such as volumetric flow as well as in assessing vascular density of normal and diseased ...
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    21. Assessment of wave propagation on surfaces of crystalline lens with phase sensitive optical coherence tomography

      Assessment of wave propagation on surfaces of crystalline lens with phase sensitive optical coherence tomography

      We propose a real-time technique based on phasesensitive swept source optical coherence tomography (PhSSSOCT) modality for noninvasive quantification of very small optical path length changes produced on the surface of a mouse crystalline lens. Propagation of submicron mechanical waves on the surface of the lens was induced by periodic mechanical stimulation. Obtained results demonstrate that the described method is capable of detecting minute damped vibrations with amplitudes as small as 30 nanometers on the lens surface and hence, PhS-SSOCT could be potentially used to assess biomechanical properties of a crystalline lens with high accuracy and sensitivity.

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    22. Construction and test of a GRIN-based optical objective

      Construction and test of a GRIN-based optical objective
      Optical fibres with their unique ability to transport light even in a coherent way (fibre bundles) and the possibility to build small volume optical pieces (Graded Index Fibres, GRIN) have a dominant role in the assembly of probes and objectives for microscopy applications requiring noninvasive and flexible operation in small and crowded spaces (in vivo microscopy, endoscopy, inspection). Nowadays, even complex observing procedures like confocal, two-photon and optical coherence tomography can be approached with fibres, making possible in vivo applications and also in place decision and processing. We present here a series of analytical simulations and practical tests made on ...
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    23. Clinical assessment of early tooth demineralization using polarization sensitive optical coherence tomography

      Clinical assessment of early tooth demineralization using polarization sensitive optical coherence tomography

      Introduction The aims of this study were to test the hypothesis that polarization sensitive-optical coherence tomography (PS-OCT) can be used to non-destructively measure and quantify the severity of the early demineralization of enamel on buccal and occlusal surfaces and assess the inhibitory effect of fluoride varnish in vivo. Methods A split mouth design was used to assess the effects of fluoride varnish on inhibiting dissolution on 20 test subjects. Orthodontic bands with a buccal window were cemented on the premolars and small incisions were produced on occlusal surfaces to serve as sites for plaque retention for enhanced demineralization. Bands were ...

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