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    1. Predictors of Retinal Atrophy in Multiple Sclerosis: A Longitudinal Study Using Spectral Domain Optical Coherence Tomography with Segmentation Analysis

      Predictors of Retinal Atrophy in Multiple Sclerosis: A Longitudinal Study Using Spectral Domain Optical Coherence Tomography with Segmentation Analysis

      Background Multiple sclerosis is an inflammatory demyelinating disease characterized by progressive axonal loss affecting mainly the inner retinal layers. Optical coherence tomography (OCT) provides in-vivo quantification of the retinal layers and allows measuring progressive retinal changes. Our objective was to assess the longitudinal changes in the retina using spectral domain OCT (SDOCT) and to identify independent predictors affecting retinal thinning in MS patients. Methods A prospective study in a tertiary care MS center was conducted to study the longitudinal retinal changes in MS patients. All subjects underwent baseline and follow up OCT assessment with segmentation analysis. Regression analysis was performed ...

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    2. Quantitative comparisons between optical coherence tomography angiography and matched histology in the human eye

      Quantitative comparisons between optical coherence tomography angiography and matched histology in the human eye

      The aim was to quantitatively compare retinal vascular detail as seen on optical coherence tomography angiography (OCTA) and matched histology in the human eye. 13 normal human donor eyes were used. The central retinal artery was cannulated after which human packed red blood cells were perfused through the retinal vasculature. Retinal vessels were imaged using a custom-built OCTA device during red blood cell perfusion. The eye was subsequently perfused with endothelial cell antibodies and the flat-mounted retina studied histologically using a confocal scanning laser microscope. Qualitative and quantitative comparisons of retinal vascular information as seen on OCTA and histology from ...

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    3. Blood vessel segmentation algorithms — Review of methods, datasets and evaluation metrics

      Blood vessel segmentation algorithms — Review of methods, datasets and evaluation metrics

      Background Blood vessel segmentation is a topic of high interest in medical image analysis since the analysis of vessels is crucial for diagnosis, treatment planning and execution, and evaluation of clinical outcomes in different fields, including laryngology, neurosurgery and ophthalmology. Automatic or semi-automatic vessel segmentation can support clinicians in performing these tasks. Different medical imaging techniques are currently used in clinical practice and an appropriate choice of the segmentation algorithm is mandatory to deal with the adopted imaging technique characteristics (e.g. resolution, noise and vessel contrast). Objective This paper aims at reviewing the most recent and innovative blood vessel ...

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    4. Influence of the Loci of Non-Cavitated Fissure Caries on Its Detection with Optical Coherence Tomography

      Influence of the Loci of Non-Cavitated Fissure Caries on Its Detection with Optical Coherence Tomography

      Objective The main objective of this study was to evaluate the accuracy of optical coherence tomography (OCT) in detecting naturally occurring non-cavitated fissure caries (NCFC) in totality and at different loci by visually assessing cross-sectional OCT scans (B-scan) with an interpretation criterion. The secondary objective was to evaluate the agreement between dimensions of NCFC measured with OCT and polarized light microscopy (PLM). Methods 71 investigation sites of sound fissure and naturally occurring NCFC on human extracted premolars were identified and scanned with a swept-source OCT. The teeth were then sectioned bucco-lingually at the investigation sites and imaged using PLM. Two ...

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    5. Phase Contrast Tomography at Lab on Chip scale by Digital Holography

      Phase Contrast Tomography at Lab on Chip scale by Digital Holography

      High-throughput single-cell analysis is a challenging target for implementing advanced biomedical applications. An excellent candidate for this aim is label-free tomographic phase microscopy (TPM). In this paper, some of the methods used to obtain TPM are reviewed, analyzing advantages and disadvantages of each of them. Moreover, an alternative tomographic technique is described for live cells analysis, and future trends of the method are foreseen. In particular, by exploiting random rolling of cells while they are flowing along a microfluidic channel, it is possible to obtain phase-contrast tomography thus obtaining complete retrieval of both 3D-position and orientation of rotating cells. Thus ...

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    6. Comparison of chorioretinal layers in rhesus macaques using spectral-domain optical coherence tomography and high-resolution histological sections

      Comparison of chorioretinal layers in rhesus macaques using spectral-domain optical coherence tomography and high-resolution histological sections

      Nonhuman primates are important preclinical models of retinal diseases because they uniquely possess a macula similar to humans. Ocular imaging technologies such as spectral-domain optical coherence tomography (SD-OCT) allow noninvasive, in vivo measurements of chorioretinal layers with near-histological resolution. However, the boundaries are based on differences in reflectivity, and detailed correlations with histological tissue layers have not been explored in rhesus macaques, which are widely used for biomedical research. Here, we compare the macular anatomy and thickness measurements of chorioretinal layers in rhesus macaque eyes using SD-OCT and high-resolution histological sections. Images were obtained from methylmethacrylate-embedded histological sections of 6 ...

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    7. In Vivo Automated Quantification of Thermally Damaged Human Tissue Using Polarization Sensitive Optical Coherence Tomography

      In Vivo Automated Quantification of Thermally Damaged Human Tissue Using Polarization Sensitive Optical Coherence Tomography

      Over the decades numerous technologies have been performed for the quantification of skin injuries, but their poor sensitivity, specificity and accuracy limits their applications. Optical coherence tomography (OCT) can be potential tool for the identification but the modern high-speed OCT system acquires huge amount of data, which will be very time-consuming and tedious process for human interpretation. Our proposed method opens the possibility of fully automated quantitative analysis based on morphological features of thermally damaged tissue, which will become biomarker for the removal of non-viable skin. The proposed method is based on multi-level ensemble classifier by dissociating morphological features (A-line ...

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    8. Indocyanine Green Dye Filling Time for Polypoidal Lesions in Polypoidal Choroidal Vasculopathy Affects the Visibility of the Lesions on OCT Angiography

      Indocyanine Green Dye Filling Time for Polypoidal Lesions in Polypoidal Choroidal Vasculopathy Affects the Visibility of the Lesions on OCT Angiography

      Purpose To elucidate the factors that affect the visibility of polypoidal lesions on OCT angiography (OCTA) based on indocyanine green angiography (ICGA) findings in eyes with polypoidal choroidal vasculopathy (PCV). Design Retrospective, consecutive case series. Participants Thirty-one eyes of 31 patients with PCV diagnosed on ICGA. Methods We compared the numbers of polyps visible on ICGA and on OCTA. The following time points and durations were determined: first appearance of dye in the choroidal arteries, first appearance of dye within a polyp, and the time it took the dye to fill entire lesions. Then we compared visible and invisible polyps ...

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    9. Spectral optical coherence tomography findings in an elderly patient with syphilitic bilateral chronic panuveitis

      Spectral optical coherence tomography findings in an elderly patient with syphilitic bilateral chronic panuveitis

      Purpose To report the spectral domain optical coherence tomography (SD-OCT) features of a focal retinitis in an elderly male patient with bilateral syphilitic panuveitis. Observations In the left eye (LE), spectral domain SD-OCT images during the active period revealed hyperreflectivity extending through the full thickness of the retina with no individualization of the layers, except for the retinal pigment epithelium. Once the lesion healed, SD-OCT imaging revealed an inner retinal atrophy and a mild disruption of the retinal pigment epithelium. Conclusions and importance In our patient, treponemal infection seemed to produce full-thickness retinal damage with partial involvement of the retinal ...

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    10. Optical coherence tomography angiography of a pigmented Fuchs' adenoma (age-related hyperplasia of the nonpigmented ciliary body epithelium) masquerading as a ciliary body melanoma

      Optical coherence tomography angiography of a pigmented Fuchs' adenoma (age-related hyperplasia of the nonpigmented ciliary body epithelium) masquerading as a ciliary body melanoma

      Purpose To report a case of age-related hypertrophy of the nonpigmented ciliary epithelium (ARH-NPCE) clinically resembling a ciliary body melanoma and report the optical coherence tomography angiography (OCTA) findings associated with this lesion. Observations A 51-year-old male was referred for evaluation of a deeply pigmented ciliary body mass with extension through the iris root. Iridocyclectomy was performed due to concern for ciliary body melanoma. Histopathologic analysis was instead consistent with ARH-NPCE, also known as Fuchs' adenoma. Prior to surgery, OCTA images revealed abnormal vasculature in the area of the lesion. Vessels in the peripheral iris approaching the lesion appeared more ...

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    11. An Automated Method for Choroidal Thickness Measurement from Enhanced Depth Imaging Optical Coherence Tomography Images

      An Automated Method for Choroidal Thickness Measurement from Enhanced Depth Imaging Optical Coherence Tomography Images

      The choroid is vascular tissue located underneath the retina and supplies oxygen to the outer retina; any damage to this tissue can be a precursor to retinal diseases. This paper presents an automated method of choroidal segmentation from enhanced depth imaging optical coherence tomography (EDI-OCT) images. The Dijkstra shortest path algorithm is used to segment the choroid-sclera interface (CSI), the outermost border of the choroid. A novel intensity-normalisation technique that is based on the depth of the choroid is used to equalise the intensity of all non-vessel pixels in the choroid region. The outer boundary of choroidal vessel and CSI ...

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    12. The EYE-MI study: A prospective acute coronary syndrome cohort evaluated by retinal optical coherence tomography angiography

      The EYE-MI study: A prospective acute coronary syndrome cohort evaluated by retinal optical coherence tomography angiography

      Background Retinal artery calibre correlates with the risk of cardiovascular events, and could serve as an inexpensive and reproducible biomarker for cardiovascular diseases. Recently, a non-invasive approach for retinal imaging with OCT angiography has been proposed to evaluate retinal blood vessel density. Methods The EYE-MI study prospectively included all consecutive patients admitted to our University Hospital for acute coronary syndrome (ACS) between October, 1st and December, 31st 2016. Patients with retinal diseases were excluded. Retinal OCT angiography was performed within 2 days after admission to assess inner retina vascular density (IRVD), based on blood flow. Results Of 212 patients admitted ...

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    13. Modern acrylic paints probed by optical coherence tomography and infrared reflectography

      Modern acrylic paints probed by optical coherence tomography and infrared reflectography

      Contemporary art is particularly delicate as the synthetic materials used for their realization are of poorer quality and durability than the traditional materials. It follows that the contemporary artworks often require imminent restorations as well as in-depth analytical studies of the constituting materials. The non-invasiveness of the scientific methods is a key issue in the diagnostics of contemporary art because it minimizes the need of sampling. In this respect, the potential of Optical Coherence Tomography (OCT) imaging to probe the internal structure of the commercial acrylic paint layers, as a function of their thickness, was investigated and compared with that ...

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    14. Agreement between Pentacam and optical coherence tomography in the assessment of iridocorneal angle width in a large healthy population

      Agreement between Pentacam and optical coherence tomography in the assessment of iridocorneal angle width in a large healthy population

      Purpose To analyze the agreement between Pentacam and optical coherence tomography (OCT) in the assessment of trabecular-iris angle (TIA) width in a large population of normal subjects. Methods A cross-sectional study was performed in 989 right eyes of 989 healthy subjects. The trabecular-iris angle (TIA) was measured in the temporal and nasal quadrants using the Pentacam (Oculus, Wetzlar, Germany), a device based on Scheimpflug technology and RTVue 100 OCT (Optovue, Fremont, CA, USA). Intraclass correlation coefficients (ICC) and Bland–Altman plots were used to evaluate agreement between these devices. Results Mean age was 49.1 ± 15.2 years (18–84 ...

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    15. All-fiber probe for optical coherence tomography with an extended depth of focus by a high-efficient fiber-based filter

      All-fiber probe for optical coherence tomography with an extended depth of focus by a high-efficient fiber-based filter

      Although methods have been proposed to maintain high transverse resolution over an increased depth range, it is not straightforward to scale down the bulk-optic solutions to minimized probes of optical coherence tomography (OCT). In this paper, we propose a high-efficient fiber-based filter in an all-fiber OCT probe to realize an extended depth of focus (DOF) while maintaining a high transverse resolution. Mode interference in the probe is exploited to modulate the complex field with controllable radial distribution. The principle of DOF extension by the fiber-based filter is theoretically analyzed. Numerical simulations are conducted to evaluate the performances of the designed ...

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    16. Difference in plaque characteristics of coronary culprit lesions in a cohort of Egyptian patients presented with acute coronary syndrome and stable coronary artery disease: An optical coherence tomography study

      Difference in plaque characteristics of coronary culprit lesions in a cohort of Egyptian patients presented with acute coronary syndrome and stable coronary artery disease: An optical coherence tomography study

      Aims This study was designed to utilize frequency-domain optical coherence tomography (FD-OCT) for assessment of plaque characteristics and vulnerability in patients with acute coronary syndrome (ACS) compared to stable coronary artery disease (SCAD). Methods and results We enrolled 48 patients; divided into an ACS-group (27 patients) and SCAD-group (21 patients) according to their clinical presentation. Hypertension and diabetes mellitus were more prevalent in SCAD group. Patients with ACS showed higher frequency of lipid-rich plaques (96.3% vs. 66.7%, P = .015), lower frequency of calcium plaques (7.4% vs. 57.1%, P < .001), and fibrous plaques (14.8% vs. 81 ...

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    17. Fouling development in direct contact membrane distillation: Non-invasive monitoring and destructive analysis

      Fouling development in direct contact membrane distillation: Non-invasive monitoring and destructive analysis

      Fouling development in direct contact membrane distillation (DCMD) for seawater desalination was evaluated combining in-situ monitoring performed using optical coherence tomography (OCT) together with destructive techniques. The non-invasive monitoring with OCT provided a better understanding of the fouling mechanism by giving an appropriate sampling timing for the membrane autopsy. The on-line monitoring system allowed linking the flux trend with the structure of fouling deposited on the membrane surface. The water vapor flux trend was divided in three phases based on the deposition and formation of different foulants over time. The initial flux decline was due to the deposition of a ...

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    18. Quantification of particulate matter attached to the bulk-biofilm interface and its influence on local mass transfer

      Quantification of particulate matter attached to the bulk-biofilm interface and its influence on local mass transfer

      A large fraction of the chemical oxygen demand (COD) in municipal wastewater is associated with the particulate matter. The presence of these particles might impose a negative impact on the mass transfer in biofilm systems when they attach to the bulk-biofilm interface. We thus investigated the impact of real wastewater particles by combining optical coherence tomography (OCT) and oxygen microsensor measurements. The deposition of wastewater particles of different size classes onto the biofilm surface was captured in 3D by means of OCT in a lab-scale flume. The thickness of the particle layer was calculated from OCT images. The influence of ...

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    19. Complementary use of Optical Coherence Tomography (OCT) and Reflection FTIR spectroscopy for in-situ non-invasive monitoring of varnish removal from easel paintings

      Complementary use of Optical Coherence Tomography (OCT) and Reflection FTIR spectroscopy for in-situ non-invasive monitoring of varnish removal from easel paintings

      Although the solvent removal of unwanted layers (e.g. aged varnishes, overpaints, oxalate patinas, dirt from easel paintings is one of the most frequently performed restoration treatments) it is questioned regarding its controllability and safety to the artwork. There is thus a need for developing suited diagnostic methodologies able to inform restorers on the chemical, optical and morphological effects of cleaning. To this aim, we have explored the possibility of complementary use of Optical Coherent Tomography (OCT) and reflection FTIR. On the one hand, the OCT technique provides cross-sectional images with varnish layers visible and thus permits for measurement of ...

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    20. Intracoronary Optical Coherence Tomography 2018 : Current Status and Future Directions

      Intracoronary Optical Coherence Tomography 2018 : Current Status and Future Directions

      The advent of intravascular imaging has been a significant advancement in visualization of coronary arteries, particularly with optical coherence tomography (OCT) that allows for high-resolution imaging of intraluminal and transmural coronary structures. Accumulating data support a clinical role for OCT in a multitude of clinical scenarios, including assessing the natural history of atherosclerosis and modulating effects of therapies, mechanisms of acute coronary syndromes, mechanistic insights into the effects of novel interventional devices, and optimization of percutaneous coronary intervention. In this state-of-the-art review, we provide an overview of the published data on the clinical utility of OCT, highlighting the areas that ...

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    21. Bruch’s membrane opening on optical coherence tomography in pediatric papilledema and pseudopapilledema

      Bruch’s membrane opening on optical coherence tomography in pediatric papilledema and pseudopapilledema

      Purpose To determine whether the diameter of Bruch’s membrane opening (BMO) can distinguish mild papilledema from pseudopapilledema using optical coherence tomography (OCT). Methods The medical records of pediatric patients with pseudopapilledma due to optic nerve head (ONH) drusen, patients with papilledema, and normal control subjects were reviewed retrospectively. All eyes underwent OCT imaging of the BMO and retinal nerve fiber layer (RNFL). Transverse horizontal diameter of the BMO and papillary height were measured. Mean BMO, papillary height, and RNFL were compared and receiver operating characteristic (ROC) curves were used to calculate the area under the curve (AUC) and determine ...

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