1. 1-24 of 1414 1 2 3 4 ... 57 58 59 »
    1. New insights from non-invasive imaging: from prospection of skin photodamages to training with mobile application

      New insights from non-invasive imaging: from prospection of skin photodamages to training with mobile application

      The incidence of non-melanoma skin cancer is on the rise and melanoma is among the most common cancers in the United States. Establishing an early diagnosis is essential for improving the prognosis of patients with skin cancer. High-resolution non-invasive imaging techniques may represent key tools for helping to identify and monitor early signs of skin cancer in seemingly healthy skin. Cumulative lifetime sun exposure leads to photoaging and photocarcinogenenis and the reaction of the skin to this solar-induced damage is balanced between the DNA repair and photoprotection defence mechanisms of melanocytes and keratinocytes. In the first part of this article ...

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    2. Noninvasive, in vivo, characterization of cutaneous metastases using a novel multimodal RCM-OCT imaging device: A case-series

      Noninvasive, in vivo, characterization of cutaneous metastases using a novel multimodal RCM-OCT imaging device: A case-series

      Background: Cutaneous metastases (CM) are clinically challenging, requiring an invasive biopsy for confirmation. A novel, RCM-OCT device combines the advantage of high-resolution reflectance confocal microscopy (RCM) images and deeper optical coherence tomography (OCT) images to aid in non-invasive diagnosis. Objective: Characterize CM using RCM-OCT device. Methods: Seven patients with suspicious CM were consented and imaged with RCM-OCT device. CM features were defined by comparing with histopathology. Tumor depths were measured on OCT and on H&E-images and correlated using Pearson test. 3D-OCT images were reconstructed to enhance tumor visualization. Results: 6/7 lesions were CM, and one was vascular ectasia ...

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    3. CGNet-assisted Automatic Vessel Segmentation for Optical Coherence Tomography Angiography

      CGNet-assisted Automatic Vessel Segmentation for Optical Coherence Tomography Angiography

      Automatic optical coherence tomography angiography (OCTA) vessel segmentation is of great significance to retinal disease diagnoses. Due to the complex vascular structure, however, various existing factors make the segmentation task challenging. This paper reports a novel end-to-end three-stage channel and position attention (CPA) module integrated graph reasoning convolutional neural network (CGNet) for retinal OCTA vessel segmentation. Specifically, in the coarse stage, both CPA and graph reasoning network (GRN) modules are integrated in between a U-shaped neural network encoder and decoder to acquire vessel confidence maps. After being directed into a fine stage, such confidence maps are concatenated with the original ...

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    4. Passively scanned, single-fiber optical coherence tomography probes for gastrointestinal devices

      Passively scanned, single-fiber optical coherence tomography probes for gastrointestinal devices

      Background/objectives: Optical coherence tomography (OCT) uses low coherence interferometry to obtain depth-resolved tissue reflectivity profiles (M-mode) and transverse beam scanning to create images of two-dimensional tissue morphology (B-mode). Endoscopic OCT imaging probes typically employ proximal or distal mechanical beam scanning mechanisms that increase cost, complexity, and size. Here, we demonstrate in the gastrointestinal (GI) tracts of unsedated human patients, that a passive, single-fiber probe can be used to guide device placement, conduct device-tissue physical contact sensing, and obtain two-dimensional OCT images via M-to-B-mode conversion. Materials and methods: We designed and developed ultrasmall, manually scannable, side- and forward-viewing single fiber-optic ...

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    5. Morphological characteristics of zebrafish's yolk sac for malformation based on orthogonal-polarization-gating optical coherence tomography

      Morphological characteristics of zebrafish's yolk sac for malformation based on orthogonal-polarization-gating optical coherence tomography

      In this study, an automatic algorithm combining an ellipsoid approximation and U-net has been presented for characterization of a zebrafish's yolk sac The polarization-difference-balanced-detection image of zebrafish was obtained based on orthogonal-polarization-gating optical coherence tomography and used to segment the yolk sac region. And ellipsoid can approximate the shape of the three-dimensional yolk sac, and the multiple parameters of volume and the three principal axes (k, l and m) can be used to quantify the yolk sac. In addition, the multiple parameters of two principal axes (l and m) and volume can distinguish the malformation from the normal controlled ...

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    6. Line-field confocal optical coherence tomography (LC-OCT) as a new tool for non-invasive differential diagnosis of pustular skin disorders

      Line-field confocal optical coherence tomography (LC-OCT) as a new tool for non-invasive differential diagnosis of pustular skin disorders

      Background: The spectrum of pustular skin disorders (PSD) is large and particularly challenging, including inflammatory, infectious and amicrobial diseases. Moreover, although pustules represent the unifying clinical feature, they can be absent or not fully developed in the early stage of the disease. The line-field confocal optical coherence tomography (LC-OCT) is a recently developed imaging technique able to perform a non-invasive, in vivo, examination of the epidermis and upper dermis, reaching very high image resolution and virtual histology. Objectives: We aimed to investigate the potentialities of LC-OCT in the non-invasive differential diagnosis of a series of 11 PSD with different etiology ...

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    7. Assessing changes in facial skin quality using noninvasive in vivo clinical skin imaging techniques after use of a topical retinoid product in subjects with moderate-to-severe photodamage

      Assessing changes in facial skin quality using noninvasive in vivo clinical skin imaging techniques after use of a topical retinoid product in subjects with moderate-to-severe photodamage

      Background Studies utilizing reflectance confocal microscopy (RCM) and dynamic optical coherence tomography (D-OCT) to assess cosmetic skin changes are limited. Methods A 12-week, open-label study was conducted using RCM and D-OCT to evaluate the effects of a topical cosmetic retinol (RET05) on subjects with facial photodamage. Study endpoints included investigator grading, standardized (VISIA-CR) and 3D photography (Antera 3D), independent RCM (VivaScope1500) and D-OCT (VivoSight) image analysis, validated FACE-Q scales, and subject questionnaires. Results Twenty-three subjects, 45- to 68-year old, with Fitzpatrick skin types II–IV completed the study. After 12 weeks of repeated application, RET05 demonstrated significant corresponding cosmetic improvements ...

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    8. Split-Window OCT biometry in pseudophakic eyes

      Split-Window OCT biometry in pseudophakic eyes

      Purpose: To determine the utility of Split-Window optical coherence tomography OCT (SW-OCT) biometry in measuring ocular axial dimensions as well as imaging the intraocular lens (IOL) and posterior capsule in pseudophakic eyes. Methods: Sixty-nine pseudophakic eyes of 69 subjects were enrolled in the study. The results of SW-OCT biometry implemented in the SD OCT device for posterior and anterior segment imaging (REVO NX, Optopol Technology) were compared with those obtained with the SS-OCT-based biometer IOLMaster 700 (Carl Zeiss Meditec). Differences in measurement values between the two biometers were determined using the paired t-test. Agreement was assessed through intraclass correlation coefficients ...

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    9. Line-field confocal optical coherence tomography of psoriasis, eczema and lichen planus: A case series with histopathological correlation

      Line-field confocal optical coherence tomography of psoriasis, eczema and lichen planus: A case series with histopathological correlation

      Background: Line-field confocal optical coherence tomography (LC-OCT) is a novel, non-invasive technique that provides in-vivo, high-resolution images in both vertical and horizontal sections. Objectives: The aim of the study was to evaluate LC-OCT imaging in some inflammatory disorders and to correlate the resulting features with histopathology. Methods: The retrospective study included patients with histopathological confirmed diagnosis of plaque psoriasis, atopic eczema and lichen planus, who were imaged with LC-OCT before the biopsy. LC-OCT was performed with the commercially available LC-OCT device. Results: A total of 15 adult patients with histopathologically proven plaque psoriasis (N: 5), atopic eczema (N: 5), and ...

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    10. Optical coherence tomography for surgical margin evaluation of excised canine cutaneous and subcutaneous tumors

      Optical coherence tomography for surgical margin evaluation of excised canine cutaneous and subcutaneous tumors

      Currently, intraoperative tumor margin imaging is not routinely utilized in veterinary medicine. Optical coherence tomography (OCT) allows for real-time assessment of tissue morphology of 1-2 mm depth. The aims of this study were 1) to compare the histologic and OCT features of excised canine skin and subcutaneous specimens, and 2) to determine the diagnostic accuracy of OCT for surgical margin evaluation. The authors hypothesized that OCT imaging would correlate well with histopathology and that OCT would be sensitive for detection of incomplete margins. Eighty dogs were prospectively enrolled. Tumors were excised and the surgical margins were imaged using a spectral ...

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    11. The use of optical coherence tomography for skin evaluation in healthy rats - A pilot study

      The use of optical coherence tomography for skin evaluation in healthy rats - A pilot study

      Background: Noninvasive diagnostic techniques allow for morphological and morphometric in vivo evaluation of the skin. Optical coherence tomography (OCT) is a method that allows visualization of dermal structures up to several 100 μm with a resolution of 3-7.5 μm. Objectives: The aim of the study was the morphological and morphometric assessment of rats' skin using SD-OCT. Animals: Fifteen male Wistar rats, aged 3 and 8 months, weighing 350-450 g. Materials and methods: The skin of the plantar metatarsal area of the right pelvic limb was assessed. The measurements were performed using Spectral Domain Optical Coherence Tomography (SD-OCT) scans and ...

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    12. Outer retinal thickness and visibility of the choriocapillaris in four distinct retinal regions imaged with spectral domain optical coherence tomography in dogs and cats

      Outer retinal thickness and visibility of the choriocapillaris in four distinct retinal regions imaged with spectral domain optical coherence tomography in dogs and cats

      Purpose: To evaluate the outer retinal band thickness and choriocapillaris (CC) visibility in four distinct retinal regions in dogs and cats imaged with spectral domain optical coherence tomography (SD-OCT). To attempt delineation of a fovea-like region in canine and feline SD-OCT scans, aided by the identification of outer retinal thickness differences between retinal regions. Methods: Spectralis® HRA + OCT SD-OCT scans from healthy, anesthetized dogs (n = 10) and cats (n = 12) were analyzed. Scanlines on which the CC was identifiable were counted and CC visibility was scored. Outer nuclear layer (ONL) thickness and the distances from external limiting membrane (ELM) to ...

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    13. Prediction of visual field defects from macular optical coherence tomography in glaucoma using cluster analysis

      Prediction of visual field defects from macular optical coherence tomography in glaucoma using cluster analysis

      Purpose To assess the accuracy of cluster analysis-based models in predicting visual field (VF) defects from macular ganglion cell-inner plexiform layer (GCIPL) measurements in glaucomatous and healthy cohorts. Methods GCIPL measurements were extracted from posterior pole optical coherence tomography (OCT), from locations corresponding to central VF test grids. Models incorporating cluster analysis methods and corrections for age and fovea to optic disc tilt were developed from 493 healthy participants, and 5th and 1st percentile limits of GCIPL thickness were derived. These limits were compared with pointwise 5th and 1st percentile limits by calculating sensitivities and specificities in an additional 40 ...

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    14. Transforming the treatment of psoriasis to the 21st century: Detecting subclinical therapeutic response to secukinumab using optical coherence tomography as a prognostic indicator

      Transforming the treatment of psoriasis to the 21st century: Detecting subclinical therapeutic response to secukinumab using optical coherence tomography as a prognostic indicator

      Background: Optical coherence tomography (OCT) is a noninvasive imaging device that scans the skin up to 2 mm in depth. OCT can capture real-time epidermal thickness (ET) measurements and detect subclinical changes in inflammatory skin diseases like eczema and psoriasis. © 2022 Wiley Periodicals LLC. Objective: To determine if measuring ET with OCT can detect a subclinical therapeutic response in psoriasis treated with the biological therapy, secukinumab (an IL-17A antagonist). Design: Phase IV, single-center, open-label, and single-arm study. Participants: Twenty-six consecutive patients with moderate to severe plaque psoriasis. Measurements: Clinical, dermoscopic, and OCT images were obtained at each visit. The clinician ...

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    15. Depth of focus extension in optical coherence tomography using ultrahigh chromatic dispersion of zinc selenide

      Depth of focus extension in optical coherence tomography using ultrahigh chromatic dispersion of zinc selenide

      We report a novel technique to overcome the depth-of-focus limitation in optical coherence tomography using chromatic dispersion of zinc selenide lens. Optical coherence tomography is an established method of optical imaging, which found numerous biomedical applications. However, the depth scanning range of high-resolution optical coherence tomography is limited by its depth of focus. Chromatic dispersion of zinc selenide lens allows to get high lateral resolution along extended depth of focus, because the different spectral components are focused at a different position along axes of light propagation. Test measurements with nanoparticle phantom show 2.8 times extension of the depth of ...

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    16. Quantitative assessment of macular and circumpapillary retinal vessel density across all stages of Leber hereditary optic neuropathy using swept source optical coherence tomography angiography

      Quantitative assessment of macular and circumpapillary retinal vessel density across all stages of Leber hereditary optic neuropathy using swept source optical coherence tomography angiography

      Purpose: To investigate the macular and circumpapillary retinal microvasculature across all stages of Leber hereditary optic neuropathy (LHON) using swept source optical coherence tomography angiography (OCTA). Methods: This prospective, multicentre, cross-sectional, observational study analysed a total of 119 eyes of 60 patients with molecularly confirmed LHON across all stages and 120 eyes of 60 control subjects. Optical coherence tomography angiography maps centred on the fovea and optic disc were obtained to measure vessel densities (VDs) in the macular superficial (SCP) and deep (DCP) capillary plexuses, and the radial peripapillary capillary plexus (RPCP) respectively. Results: In asymptomatic eyes, only the SCP ...

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    17. software development TO OPTIMIZE THE minimal detectable difference IN huMAN AIRWAY IMAGES CAPTURED USING optical coherence tomography

      software development TO OPTIMIZE THE minimal detectable difference IN huMAN AIRWAY IMAGES CAPTURED USING optical coherence tomography

      Optical coherence tomography (OCT) is an imaging methodology that can be used to assess human airways. OCT avoids the harmful effects of ionizing radiation and has a high spatial resolution making it well suited for imaging the structure of small airways. Analysis of OCT airway images has typically been performed manually by tracing the airway with a relatively high coefficient of variation. The purpose of this study was to develop an analysis tool to reduce the inter- and intra-observer reproducibility of OCT and improve the ability to detect differences in airways. OCT images from healthy, young human volunteers were used ...

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    18. No optical coherence tomography changes in premanifest Huntington's disease mutation carriers far from disease onset

      No optical coherence tomography changes in premanifest Huntington's disease mutation carriers far from disease onset

      Background: Spectral-domain optical coherence tomography (OCT) may detect retinal changes as a biomarker in neurodegenerative diseases like manifest Huntington's disease (HD). We investigate macular retinal layer thicknesses in a premanifest HD (pre-HD) cohort and healthy controls (HC). Methods: Pre-HD mutation carriers underwent standardized ratings and a preset macular OCT scan. Thickness values were determined for each sector of all macular retinal layers, the mean of all sectors and the mean of the inner ring (IR, 3 mm) after segmentation (Heyex segmentation batch). HC were retrospectively included from an existing database. The IR thickness of the ganglion cell layer (GCL ...

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    19. Compressive-sensing swept-source optical coherence tomography angiography with reduced noise

      Compressive-sensing swept-source optical coherence tomography angiography with reduced noise

      Optical coherence tomography angiography (OCTA), as a functional extension of optical coherence tomography (OCT), has exhibited a great potential to aid in clinical diagnostics. Currently, OCTA still suffers from motion artifact and noise. Therefore, in this paper, we propose to implement compressive sensing (CS) on B-scans to reduce motion artifact by increasing B-scan rate. Meanwhile, a noise-reduction filter is specially designed by combining CS, Gaussian filter, and Median filter. Specially, CS filtering is realized by averaging multiple CS repetitions on en-face OCTA images with varied sampling functions. The method is evaluated on in vivo OCTA images of human skin. The ...

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    20. The response of dual-species bacterial biofilm to 2% and 5% NaOCl mixed with etidronic acid: a laboratory real-time evaluation using optical coherence tomography

      The response of dual-species bacterial biofilm to 2% and 5% NaOCl mixed with etidronic acid: a laboratory real-time evaluation using optical coherence tomography

      Aim: The addition of etidronic acid (HEDP) to sodium hypochlorite (NaOCl) could increase the antibiofilm potency of the irrigant, while maintaining the benefits of continuous chelation. Studies conducted so far have shown that mixing HEDP with NaOCl solutions of relatively low concentration does not compromise the antibiofilm efficacy of the irrigant. However, the working lifespan of NaOCl may decrease resulting in a reduction of its antibiofilm efficacy over time (efficiency). In this regard, continuous irrigant replenishment needs to be examined. This study investigated the response of a dual-species biofilm when challenged with 2% and 5% NaOCl mixed with HEDP for ...

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    21. Longitudinal assessment of the effect of alkali burns on corneal biomechanical properties using optical coherence elastography

      Longitudinal assessment of the effect of alkali burns on corneal biomechanical properties using optical coherence elastography

      Eye injury due to alkali burn is a severe ocular trauma that can profoundly affect corneal structure and function, including its biomechanical properties. Here, we assess the changes in the mechanical behavior of mouse corneas in response to alkali-induced injury by conducting longitudinal measurements using optical coherence elastography (OCE). A non-contact air-coupled ultrasound transducer was used to induce elastic waves in control and alkali-injured mouse corneas in vivo, which were imaged with phase-sensitive optical coherence tomography. Corneal mechanical properties were estimated using a modified Rayleigh-Lamb wave model, and results show that Young's modulus of alkali burned corneas were significantly ...

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    22. Optical coherence tomography assessment of acute thrombogenicity at bifurcation sites using different stenting techniques: A porcine arteriovenous shunt study

      Optical coherence tomography assessment of acute thrombogenicity at bifurcation sites using different stenting techniques: A porcine arteriovenous shunt study

      Objectives We aimed to compare bare-metal stents (BMS), durable-polymer everolimus-eluting stents (DP-EES), and abluminal biodegradable-polymer sirolimus-eluting stents (ABP-SES) in the bifurcation model setup. Background The mechanism of thrombogenicity, which differs among second-generation stents implanted using double-kissing (DK) crush or culotte stenting techniques, remains unclear. We have shown previously that setting up a porcine arteriovenous shunt model is feasible and useful to assess thrombogenicity at vessel bifurcation points. Methods Six porcine shunt models were prepared for the comparison between DK crush and culotte stenting techniques using BMS, DP-EES, and ABP-SES. Intracoronary imaging with high-resolution optical coherence tomography (OCT) was performed to ...

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    23. CVIS: Automated OCT-scan-based software application for the measurements of choroidal vascularity index and choroidal thickness

      CVIS: Automated OCT-scan-based software application for the measurements of choroidal vascularity index and choroidal thickness

      Purpose: To develop an automated image recognition software for the objective quantification of choroidal vascularity index (CVI) and choroidal thickness (CT) at different choroidal locations on images obtained from enhanced depth imaging optical coherence tomography (EDI-OCT), and to validate its reliability and investigate the difference and correlation between measurements made by manual and software. Methods: A total of 390 EDI-OCT scans, captured from 130 eligible emmetropic or myopic subjects, were categorized into four grades in terms of their accessibility to identify the choroidal-scleral interface (CSI) and were further assessed for CT and CVI at five locations (subfoveal, nasal, temporal, superior ...

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    24. Evaluation of neuroretinal integrity in optical coherence tomography-graded eyes with partial-thickness macular holes

      Evaluation of neuroretinal integrity in optical coherence tomography-graded eyes with partial-thickness macular holes

      Purpose: To evaluate neuroretinal integrity in different subtypes of optical coherence tomography (OCT)-graded partial-thickness macular holes. Methods: Fovea-centred SD-OCT images (Cirrus, Carl Zeiss Meditec AG; Spectralis, Heidelberg Engineering GmbH) and visual acuity (VA) acquired at every visit were analysed by two retina specialists retrospectively in 71 eyes of 65 patients. Partial-thickness macular holes were classified as lamellar macular hole (LMH), epiretinal membrane foveoschisis (ERMF) or macular pseudohole (MPH). Results: Lamellar macular hole, ERMF and MPH were diagnosed in 33 (47%), 31 (43%) and 7 (10%) eyes with a VA of 0.18 ± 0.25, 0.15 ± 0.2, and ...

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