1. 985-1008 of 1020 « 1 2 ... 39 40 41 42 43 »
    1. 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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    2. 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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    3. 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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    4. 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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    5. 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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    6. 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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    7. 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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    8. 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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    9. 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
    10. 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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    11. 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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    12. 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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    13. 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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    14. 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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    15. 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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    16. Intra and interoperator reproducibility of retinal nerve fibre and macular thickness measurements using Cirrus Fourier-domain OCT

      Intra and interoperator reproducibility of retinal nerve fibre and macular thickness measurements using Cirrus Fourier-domain OCT
      Purpose:  To test intrasession, intersession, intervisit and interoperator reproducibility of retinal nerve fibre (RNFL) measurements and retinal thickness in healthy subjects using Cirrus Fourier-domain optical coherence tomography (OCT) (Carl Zeiss Meditec, Inc).Methods:  Seventy-two eyes of 72 healthy subjects were included in the study. All the eyes underwent three 512 × 128 volume cube centred on the fovea and three 360° circular scans centred on the optic disc by one observer. This sequence was redone by another observer on a second visit within a 2-week period. Descriptive statistics, analysis of variance, intraclass correlation coefficients (ICCs) and coefficients of variation (COVs) were ...
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    17. Cross-polarization optical coherence tomography for early bladder-cancer detection: statistical study

      Cross-polarization optical coherence tomography for early bladder-cancer detection: statistical study
      The capabilities of cross-polarization optical coherence tomography (CP OCT) for early bladder-cancer detection are assessed in statistical study and compared with the traditional OCT. Unlike the traditional OCT that demonstrates images only in copolarization, CP OCT acquires images in cross-polarization and copolarization simultaneously. 116 patients with localized flat suspicious lesions in the bladder were enrolled, 360 CP OCT images were obtained and analyzed. CP OCT demonstrated sensitivity 93.7% (vs. 81.2%, <0.0001), specificity 84% (vs. 70.0%, <0.001) and accuracy 85.3% (vs. 71.5%, <0.001) in detecting flat malignant bladder lesions, which is significantly better ...
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    18. Perimetric and peri-papillary nerve fibre layer thickness findings in multiple sclerosis

      Perimetric and peri-papillary nerve fibre layer thickness findings in multiple sclerosis
      Background and purpose:  Several previous studies have employed optical coherence tomography (OCT) of the optic disc and ‘white-on-white’ automated perimetry to evaluate optic neuritis (ON) associated with multiple sclerosis (MS). This study employed OCT, white-on-white automated perimetry as well as ‘blue-on-yellow’ automated perimetry to evaluate MS patients with or without episodes of ON. Methods:  The MS group consisted of 56 patients with MS (27 patients with no history of ON in both eyes and 29 patients with at least one ON attack in one or both eyes), whereas the control group consisted of 56 age- and sex-matched healthy subjects. All ...
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    19. Wavelength swept amplified spontaneous emission source for high speed retinal optical coherence tomography at 1060 nm

      Wavelength swept amplified spontaneous emission source for high speed retinal optical coherence tomography at 1060 nm
      The wavelength swept amplified spontaneous emission (ASE) source presented in this paper is an alternative approach to realize a light source for high speed swept source optical coherence tomography (OCT). ASE alternately passes a cascade of different optical gain elements and tunable optical bandpass filters. In this work we show for the first time a wavelength swept ASE source in the 1060 nm wavelength range, enabling high speed retinal OCT imaging. We demonstrate ultra-rapid retinal OCT at a line rate of 170 kHz, a record sweep rate at 1060 nm of 340 kHz with 70 nm full sweep width, enabling ...
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    20. Comparison of the influence of cataract and pupil size on retinal nerve fibre layer thickness measurements with time domain and spectral domain optical coherence tomography

      Comparison of the influence of cataract and pupil size on retinal nerve fibre layer thickness measurements with time domain and spectral domain optical coherence tomography
      Background: To investigate the effect of cataract and pupil size on retinal nerve fibre layer (RNFL) thickness measurements using spectral-domain optical coherence tomography (Cirrus OCT) and to compare against time-domain OCT (Stratus OCT). Design: Prospective, hospital-based study. Participants or Samples: 25 eyes from 25 normal subjects undergoing cataract surgery. Methods: 3 RNFL thickness measurements were taken before and after dilation, pre-and post-operatively, using Cirrus 200x200 Optic Disc Scan and Stratus Fast RNFL Scan. Main Outcome Measures: Linear regression, intraclass correlation coefficient (ICC), and coefficient of variation analysis of RNFL thickness measurements. Results: Cataract removal caused significant increase in RNFL measurements ...
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    21. Quantifying glucose permeability and enhanced light penetration in ex vivo human normal and cancerous esophagus tissues with optical coherence tomography

      Quantifying glucose permeability and enhanced light penetration in ex vivo human normal and cancerous esophagus tissues with optical coherence tomography

      We report our pilot results on quantification of glucose (G) diffusion permeability in human normal esophagus and ESCC tissues in vitro by using OCT technique. The permeability coefficient of 40% aqueous solution of G was found to be (1.74±0.04)×10–5 cm/s in normal esophagus and (2.45±0.06)×10–5 cm/s in ESCC tissues. The results from this study indicate that ESCC tissues had a higher permeability coefficient compared to normal esophageal tissues, and the light penetration depths gradually increase with the increase of applied topically with G time for the normal esophageal ...

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    22. Phenotyping Airways Disease With Optical Coherence Tomography

      Phenotyping Airways Disease With Optical Coherence Tomography

      Airway diseases are a major concern around the world. However, the pace of new drug and biomarker discovery has lagged behind those of other common disorders such as cardiovascular diseases and diabetes. One major barrier in airways research has been the inability to accurately visualize large and small airway remodeling or dysplastic/neoplastic (either pre or early cancerous) changes using non or minimally invasive instruments. The advent of optical coherence tomography (OCT) has the potential to revolutionize airway research and management by allowing investigators and clinicians to visualize the airway with resolution approaching histology without exposing patients to harmful effects ...

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    23. Interpretation of RNFLT values in multiple sclerosis-associated acute optic neuritis using high-resolution SD-OCT device

      Interpretation of RNFLT values in multiple sclerosis-associated acute optic neuritis using high-resolution SD-OCT device

      Purpose:  Optical coherence tomography (OCT) has emerged as the technique of choice in measuring the retinal nerve fibre layer (RNFL) quantitatively. It is suggested that RNFL reduction may correlate with lesion burden and diffuse axonal degeneration in the whole CNS of patients with multiple sclerosis (MS). However, RNFL changes because of optic neuritis (ON) must be taken into account.Methods:  Twenty-three patients with acute ON (46 eyes) associated with clinical definite MS (23 ON eyes, 23 fellow eyes) and 23 sex- and age-matched healthy controls were studied. Retinal nerve fibre layer thickness (RNFLT) was measured at baseline, using a high-resolution ...

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    24. A comparison of imaging methodologies for 3D tissue engineering

      A comparison of imaging methodologies for 3D tissue engineering
      Imaging of cells in two dimensions is routinely performed within cell biology and tissue engineering laboratories. When biology moves into three dimensions imaging becomes more challenging, especially when multiple cell types are used. This review compares imaging techniques used regularly in our laboratory in the culture of cells in both two and three dimensions. The techniques reviewed include phase contrast microscopy, fluorescent microscopy, confocal laser scanning microscopy, electron microscopy, and optical coherence tomography. We compare these techniques to the current “gold standard” for imaging three-dimensional tissue engineered constructs, histology.
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    985-1008 of 1020 « 1 2 ... 39 40 41 42 43 »
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