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    1. Morphomechanics of dermis-A method for non-destructive testing of collagenous tissues

      Morphomechanics of dermis-A method for non-destructive testing of collagenous tissues

      Background Collagenous tissues store, transmit and dissipate elastic energy during mechanical deformation. In skin, mechanical energy is stored during loading and then is dissipated, which protects skin from mechanical failure. Thus, energy storage (elastic properties) and dissipation (viscous properties) are important characteristics of extracellular matrices (ECMs) that support the cyclic loading of ECMs without tissue failure. Methods Uniaxial stress-strain measurements on decellularized human dermis have been made and compared to results of a non-destructive technique involving optical coherence tomography (OCT) combined with vibrational analysis. In addition, Poisson's ratio has been determined for tensile deformation of decellularized dermis. Results The ...

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      Mentions: Mark C. Pierce
    2. Morphomechanics of dermis-A method for non-destructive testing of collagenous tissues

      Morphomechanics of dermis-A method for non-destructive testing of collagenous tissues

      Background Collagenous tissues store, transmit and dissipate elastic energy during mechanical deformation. In skin, mechanical energy is stored during loading and then is dissipated, which protects skin from mechanical failure. Thus, energy storage (elastic properties) and dissipation (viscous properties) are important characteristics of extracellular matrices (ECMs) that support the cyclic loading of ECMs without tissue failure. Methods Uniaxial stress-strain measurements on decellularized human dermis have been made and compared to results of a non-destructive technique involving optical coherence tomography (OCT) combined with vibrational analysis. In addition, Poisson's ratio has been determined for tensile deformation of decellularized dermis. Results The ...

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    3. Fractional laser-assisted drug uptake: Impact of time-related topical application to achieve enhanced delivery

      Fractional laser-assisted drug uptake: Impact of time-related topical application to achieve enhanced delivery

      Background and Objective Ablative fractional laser (AFXL) is acknowledged to increase uptake of topically applied agents in skin. AFXL channels gradually close over time, which may impair this capability. The time frame for applying a drug after AFXL exposure remains to be established. The aim of this study, was to investigate the importance of time-related topical application after AFXL exposure and to relate resultant uptake in skin with AFXL channel morphology and skin integrity. Study Design/Materials and Methods Buttock skin of healthy volunteers ( n  = 11) was exposed to 10,600 nm fractional CO 2 laser using 5% density, 120 ...

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      Mentions: Mette Mogensen
    4. Predicting the intereye asymmetry in functional and structural damage in glaucoma using automated pupillography

      Predicting the intereye asymmetry in functional and structural damage in glaucoma using automated pupillography

      Purpose To predict the intereye asymmetry in functional (mean deviation, MD on visual field, VF) and structural (retinal nerve fibre layer, RNFL and ganglion cell complex, GCC thickness on spectral domain optical coherence tomography, SDOCT) measurements in glaucoma using the automated pupillography parameters. Methods Fifty-nine subjects with a diagnosis of either glaucoma or glaucoma suspect underwent automated pupillography along with VF and SDOCT examinations. Association between pupillography and the absolute intereye difference in MD, RNFL and GCC measurements was evaluated using regression analysis after accounting for the multicollinearity. Results Univariate regression analysis showed statistically significant associations (p < 0.05) between ...

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    5. Dynamic nanomechanical analysis of the vocal fold structure in excised larynges

      Dynamic nanomechanical analysis of the vocal fold structure in excised larynges

      Objectives/Hypothesis Quantification of clinical outcomes after vocal fold (VF) interventions is challenging with current technology. High-speed digital imaging and optical coherence tomography (OCT) of excised larynges assess intact laryngeal function, but do not provide critical biomechanical information. We developed a protocol to quantify tissue properties in intact, excised VFs using dynamic nanomechanical analysis (nano-DMA) to obtain precise biomechanical properties in the micrometer scale. Study Design Experimental animal study. Methods Three pig larynges were bisected in the sagittal plane, maintaining an intact anterior commissure, and subjected to nano-DMA at nine locations with a 250-μm flat-tip punch and frequency sweep ...

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    6. Melanoma diagnosis may be a pitfall for optical coherence tomography assessment of equivocal amelanotic or hypomelanotic skin lesions

      Melanoma diagnosis may be a pitfall for optical coherence tomography assessment of equivocal amelanotic or hypomelanotic skin lesions

      melanotic and hypomelanotic skin lesions can be difficult to diagnose clinically and dermoscopically. 1-3 Evidence is emerging that optical coherence tomography (OCT) can detect superficial basal cell carcinoma (sBCC) with good sensitivity (79-95.7%) and specificity (75.3-96%). 4 Given that sBCC is a common problem 4 , and that it may be treated noninvasively 5 , the potential benefits from using OCT as an adjunct to clinical diagnosis are high. However, if OCT is used without histopathological confirmation in this setting, there is a risk that more clinically aggressive malignant pathology, such as amelanotic /hypomelanotic melanoma (AHM), may be misdiagnosed and ...

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    7. Fractal analysis of en face tomographic images obtained with full field optical coherence tomography

      Fractal analysis of en face tomographic images obtained with full field optical coherence tomography

      The quantitative modeling of the imaging signal of pathological areas and healthy areas is necessary to improve the specificity of diagnosis with tomographic en face images obtained with full field optical coherence tomography (FFOCT). In this work, we propose to use the depth-resolved change in the fractal parameter as a quantitative specific biomarker of the stages of disease. The idea is based on the fact that tissue is a random medium and only statistical parameters that characterize tissue structure are appropriate. We successfully relate the imaging signal in FFOCT to the tissue structure in terms of the scattering function and ...

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      Mentions: Wanrong Gao
    8. Impact of retinal pigment epithelium pathology on spectral-domain optical coherence tomography-derived macular thickness and volume metrics and their intersession repeatability

      Impact of retinal pigment epithelium pathology on spectral-domain optical coherence tomography-derived macular thickness and volume metrics and their intersession repeatability

      Background To determine the impact of retinal pigment epithelium (RPE) pathology on intersession repeatability of retinal thickness and volume metrics derived from Spectralis spectral-domain optical coherence tomography (SD-OCT). Design Prospective cross-sectional single centre study. Participants 56 eyes of 56 subjects were divided into 3 groups: (A) normal RPE band (25 eyes), (B) RPE elevation: macular soft drusen (13 eyes) and (C) RPE attenuation: geographic atrophy or inherited retinal diseases (18 eyes). Methods Each subject underwent three consecutive follow-up macular raster scans (61 B-scans at 119 micron separation) at 1-month intervals. Main outcome measures Retinal thicknesses and volumes for each zone ...

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    9. A method to study the hemodynamics of chicken embryo's aortic arches using optical coherence tomography

      A method to study the hemodynamics of chicken embryo's aortic arches using optical coherence tomography

      Congenital cardiovascular defects are the leading cause of birth defect related death. It has been hypothesized that fluid mechanical forces of embryonic blood flow affect cardiovascular development and play a role in congenital malformations. Studies in small animal embryos can improve our understanding of congenital malformations and can lead to better treatment. We present a feasibility study in which high-resolution optical coherence tomography (OCT) and computational fluid dynamics (CFD) are combined to provide quantitative analysis of the embryonic flow mechanics and the associated anatomy in a small animal model.

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    10. Comparison of corneal measurements in keratoconus using swept-source optical coherence tomography and combined Placido–Scheimpflug imaging

      Comparison of corneal measurements in keratoconus using swept-source optical coherence tomography and combined Placido–Scheimpflug imaging

      Purpose The aim of this study was to provide a comprehensive comparison of reliability of corneal topographic measurements in keratoconic eyes using swept-source optical coherence tomography (OCT) and a combined Placido–Scheimpflug imaging. Methods A total of 30 eyes of 30 patients were included. The mean age was 31.2 ± 8.4 years. Two consecutive topographic measurements were obtained for one eye of each patient using swept-source OCT (CASIA) and combined Placido–Scheimpflug imaging (TMS-5). Test–retest reliability of CASIA and TMS-5 measurements including central corneal thickness (CCT) and thinnest corneal thickness (TCT), keratometry at steep (Ks) and flat (Kf ...

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      Mentions: Marco Yu
    11. A sloped piecemeal Gaussian model for characterising foveal pit shape

      A sloped piecemeal Gaussian model for characterising foveal pit shape

      Purpose High-quality optical coherence tomography (OCT) macular scans make it possible to distinguish a range of normal and diseased states by characterising foveal pit shape. Existing mathematical models lack the flexibility to capture all known pit variations and thus characterise the pit with limited accuracy. This study aimed to develop a new model that provides a more robust characterisation of individual foveal pit variations. Methods A Sloped Piecemeal Gaussian (SPG) model, consisting of a linear combination of a tilted line and a piecemeal Gaussian function (two halves of a Gaussian connected by a separate straight line), was developed to fit ...

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    12. Commentary on the Diagnostic Utility of Non-invasive Imaging Devices for Field Cancerization

      Commentary on the Diagnostic Utility of Non-invasive Imaging Devices for Field Cancerization

      In this issue of Experimental Dermatology , Marneffe and collegues present a practical algorithmic guide to differentiating actinic keratosis (AK) from normal skin and squamous cell carcinoma (SCC) using high-definition optical coherence tomography (HD-OCT), outlining steps and markers to guide both novice and more experienced skin cancer experts (1).

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    13. Comparison of acute expansion of bioresorbable vascular scaffolds versus metallic drug-eluting stents in different degrees of calcification

      Comparison of acute expansion of bioresorbable vascular scaffolds versus metallic drug-eluting stents in different degrees of calcification

      Objectives The acute expansion of bioresorbable vascular scaffolds (BRS) and drug-eluting stents (DES) in lesions with different extent of calcification was compared by Optical Coherence Tomography (OCT). Background The acute mechanical performance of polymeric BRS in calcified lesions is poorly understood. Methods Acute device performance in lesions treated with either BRS( N  = 50) or DES ( N  = 50) was compared using Optical Coherence Tomography (OCT). According to angiographic degree of calcification the lesions were divided in three groups: no/mild, moderate and heavy calcification. Device performance was assessed with the following parameters by OCT: mean scaffold area, eccentricity index (EI), symmetry ...

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    14. Optical coherence tomography angiography in age-related macular degeneration: persistence of vascular network in quiescent choroidal neovascularization

      Optical coherence tomography angiography in age-related macular degeneration: persistence of vascular network in quiescent choroidal neovascularization

      This study was supported by the Werner H. Spross Foundation (Zurich, Switzerland). The ‘Stiftung wissenschaftliche Forschung, Fonds Ophthalmologie, City Hospital Triemli’ received research grants from Novartis Schweiz AG and Bayer Schweiz AG and payments for invited talks or advisory board participations for M.B and S.M. from Allergan, Novartis, Alimera, Bayer, Roche and Clanotech. None of the authors above has any conflict of interest related to this research. This study was presented as an e-poster (POS- 6771) at the 15th EURETINA Congress in Nice, France (17. – 20.09.2015).

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      Mentions: Stephan Michels
    15. Laser thermal therapy monitoring using complex differential variance in optical coherence tomography

      Laser thermal therapy monitoring using complex differential variance in optical coherence tomography

      Conventional thermal therapy monitoring techniques based on temperature are often invasive, limited by point sampling, and are indirect measures of tissue injury, while techniques such as magnetic resonance and ultrasound thermometry are limited by their spatial resolution. The visualization of the thermal coagulation zone at high spatial resolution is particularly critical to the precise delivery of thermal energy to epithelial lesions. In this work, an integrated thulium laser thermal therapy monitoring system was developed based on complex differential variance (CDV), which enables the 2D visualization of the dynamics of the thermal coagulation process at high spatial and temporal resolution with ...

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    16. Semi-automated ICRS scoring of equine articular cartilage lesions in optical coherence tomography images

      Semi-automated ICRS scoring of equine articular cartilage lesions in optical coherence tomography images

      Background Arthroscopic optical coherence tomography (OCT) is a promising tool for detailed evaluation of articular cartilage injuries. However, OCT-based articular cartilage scoring still relies on the operator's visual estimation. Objectives To test the hypothesis that semi-automated ICRS (International Cartilage Repair Society) scoring of chondral lesions seen in OCT images could enhance intra- and inter-observer agreement of the scoring and its accuracy. Study design Validation study, using equine cadaver tissue. Methods Osteochondral samples ( n = 99) were prepared from eighteen equine metacarpophalangeal joints and imaged using OCT. Custom-made software was developed for semi-automated ICRS scoring of cartilage lesions on OCT images ...

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    17. The association between retinal nerve fibre layer thickness and N-acetyl aspartate levels in multiple sclerosis brain normal-appearing white matter: a longitudinal study using magnetic resonance spectroscopy and optical coherence tomography

      The association between retinal nerve fibre layer thickness and N-acetyl aspartate levels in multiple sclerosis brain normal-appearing white matter: a longitudinal study using magnetic resonance spectroscopy and optical coherence tomography

      Background and purpose N -acetyl aspartate (NAA) assessed using proton magnetic resonance spectroscopy ( 1 H MRS) has a high pathological specificity for axonal density. Retinal nerve fibre layer thickness (RNFLT) measured by using optical coherence tomography is increasingly used as a surrogate marker of neurodegeneration in multiple sclerosis (MS). Our aim was to investigate the relation between RNFLT and NAA/creatine in brain normal-appearing white matter (NAWM), their dynamics over time and the association with clinical outcome measures in relapsing MS. T2 WM lesions served as control tissue. Methods Forty-three MS patients underwent standardized neurological examination including the Expanded Disability ...

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    18. Simplifying the assessment of human breast cancer by mapping a micro-scale heterogeneity index in optical coherence elastography

      Simplifying the assessment of human breast cancer by mapping a micro-scale heterogeneity index in optical coherence elastography

      Surgical treatment of breast cancer aims to identify and remove all malignant tissue. Intraoperative assessment of tumor margins is, however, not exact; thus, re-excision is frequently needed, or excess normal tissue is removed. Imaging methods applicable intraoperatively could help to reduce re-excision rates whilst minimizing removal of excess healthy tissue. Optical coherence elastography (OCE) has been proposed for use in breast-conserving surgery; however, intraoperative interpretation of complex OCE images may prove challenging. Observations of breast cancer on multiple length scales, by OCE, ultrasound elastography, and atomic force microscopy, have shown an increase in the mechanical heterogeneity of malignant breast tumors ...

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