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    1. Cross-Polarization Optical Coherence Tomography with Active Maintenance of the Circular Polarization of a Sounding Wave in a Common Path System

      Cross-Polarization Optical Coherence Tomography with Active Maintenance of the Circular Polarization of a Sounding Wave in a Common Path System

      We consider a cross-polarization optical coherence tomography system with a common path for the sounding and reference waves and active maintenance of the circular polarization of a sounding wave. The system is based on the formation of birefringent characteristics of the total optical path, which are equivalent to a quarter-wave plate with a 45° orientation of its optical axes with respect to the linearly polarized reference wave. Conditions under which any light-polarization state can be obtained using a two-element phase controller are obtained. The dependence of the local cross-scattering coefficient of light in a model medium and biological tissue on ...

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    2. One-year optical coherence tomography findings in patients with late and very-late stent thrombosis treated with intravascular imaging guided percutaneous coronary intervention

      One-year optical coherence tomography findings in patients with late and very-late stent thrombosis treated with intravascular imaging guided percutaneous coronary intervention

      Patients with late/very-late stent thrombosis (ST) are at high risk of recurrent-ST. The mechanisms of recurrent-ST are largely unknown. The objective is to describe the 1-year optical coherence tomography (OCT) findings of patients suffering from late/very-late ST treated with intravascular imaging guided percutaneous coronary intervention (PCI). All consecutive patients with late/very-late ST undergoing intravascular imaging guided PCI were screened to undergo coronary angiography and OCT examination at 1 year. Patients were classified according to the observation of stent malapposition as most contributing cause of the ST. Thirty-four patients were included. Stent malapposition was observed in 17 (50 ...

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    3. Differences between first-generation and second-generation drug-eluting stent regarding in-stent neoatherosclerosis characteristics: an optical coherence tomography analysis

      Differences between first-generation and second-generation drug-eluting stent regarding in-stent neoatherosclerosis characteristics: an optical coherence tomography analysis

      We compared first-generation and second-generation drug-eluting stent (DES) with respect to neoatherosclerosis using optical coherence tomography or optical frequency domain imaging. In-stent restenoses in 102 first-generation and 114 second-generation DES were retrospectively assessed. Neoatherosclerosis, which was defined as the presence of lipid-laden neointima or calcification inside a stent, was observed in 33 (27.2%) and 31 (32.4%) lesions in the first-generation and second-generation DES respectively. In the first-generation DES group, the lipid length was significantly longer (5.5 ± 3.8 vs. 3.1 ± 2.1 mm, P  = 0.0007), the lipid arc was significantly larger (324 ± 70° vs. 250 ...

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    4. Optical coherence tomography in STEMI with bioresorbable scaffold: possible cause of coronary flow impairment? A sub-study from the Prague 19 trial

      Optical coherence tomography in STEMI with bioresorbable scaffold: possible cause of coronary flow impairment? A sub-study from the Prague 19 trial

      This study assessed the Optical Coherence Tomography (OCT) impact on the coronary flow in ST-elevation myocardial infarction (STEMI) after bioresorbable scaffold implantation. Only few data about OCT use in STEMI are available and coronary flow before and after OCT is not well studied yet. 54 patients with OCT performed at the end of procedure from the Prague 19 trial were selected and coronary flow was evaluated as TIMI frame count (TFC) before and just after OCT. Significant increase in TIMI frame count after OCT [from 9.5 (6.75–12.25) to 11.5 (8–15.25) frames; p = 0 ...

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    5. The Effect of Glatiramer Acetate on Retinal Nerve Fiber Layer Thickness in Patients with Relapsing–Remitting Multiple Sclerosis: A Longitudinal Optical Coherence Tomography Study

      The Effect of Glatiramer Acetate on Retinal Nerve Fiber Layer Thickness in Patients with Relapsing–Remitting Multiple Sclerosis: A Longitudinal Optical Coherence Tomography Study

      Background Optical coherence tomography (OCT) is a technique that allows for the assessment of retinal nerve fiber layer thickness (RNFLT) and total macular volume (TMV), which reflect neuroaxonal integrity within the retina. As such it has been used in multiple sclerosis (MS) to study neurodegeneration. Glatiramer acetate (GA) is a widely used treatment for MS, which is suggested to have a possible neuroprotective role. Objective The aim of this study was to assess RFNLT and TMV changes in relapsing–remitting MS (RRMS) patients who started treatment with GA and were followed for a 24-month period. Methods A cohort of 60 ...

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    6. Optical Coherence Tomography for Brain Imaging (Book Chapter)

      Optical Coherence Tomography for Brain Imaging (Book Chapter)

      Optical coherence tomography (OCT) is an imaging technique based on the detection of light back-reflected or backscattered by tissue. Based on the principles of low-coherence interferometry, OCT provides rapid volumetric imaging with micrometer-scale resolution. OCT has been massively successful in ophthalmology where it became a routine tool for retinal diagnostics. In recent years, however, OCT has also been applied to other fields including—amongst others—cardiovascular imaging, endoscopy of the gastrointestinal tract, and neuroimaging. In the brain and other neural tissues, OCT provides contrast for tissue microstructures and enables noninvasive in vivo and in vitro imaging with high resolution. Novel ...

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      Mentions: Bernhard Baumann
    7. Investigation of retinal nerve fiber layer thickness and ganglion cell layer-inner plexiform layer thickness in patients with optic pathway gliomas

      Investigation of retinal nerve fiber layer thickness and ganglion cell layer-inner plexiform layer thickness in patients with optic pathway gliomas

      Purpose This study aimed to compare the optical coherence tomography (OCT) findings of optic pathway glioma (OPG) patients (sporadic or secondary to neurofibromatosis type 1, NF1) with NF1 without OPG patients and healthy controls. Methods This was a prospective, case-control study in which 27 patients (13 with OPGs and 14 with NF1 without OPGs) and 13 control subjects were included. The retinal nerve fiber layer (RNFL) thickness, macular thickness, and ganglion cell layer-inner plexiform layer (GCL-IPL) thickness findings measured using OCT and the results were compared between the groups. Results The macular thickness was significantly lower in the OPG group ...

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    8. Equidistant Recording of the Spectral Components in Ultra-Wideband Spectral-Domain Optical Coherence Tomography

      Equidistant Recording of the Spectral Components in Ultra-Wideband Spectral-Domain Optical Coherence Tomography

      We develop an effective method for reducing nonequidistance when recording the spectral components of an interference signal in ultra-wideband spectral-domain optical coherence tomography. For this purpose, a corrector consisting of two identical prisms is used in a diffraction-grating spectrometer. The corrector rotation with respect to the diffraction-grating plane and a variation in the angle between the corrector elements allow one to adjust the equidistant spatial distribution of the spectral components in the photoreceiver array. It is shown experimentally that the developed method substitutes digital correction and leads to a significant reduction of the computational load in the optical coherence tomography ...

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    9. Optical coherence tomography and confocal laser scanning microscopy as non-invasive tools in the diagnosis of sinonasal inverted papilloma: a pilot study

      Optical coherence tomography and confocal laser scanning microscopy as non-invasive tools in the diagnosis of sinonasal inverted papilloma: a pilot study

      Optical coherence tomography (OCT) and confocal laser scanning microscopy (CLSM) are light-based imaging techniques that allow for a visualization of microscopic tissue properties in vivo. Our study was to examine whether they allow for differentiation of inverted papilloma (IP) from nasal polyps (NP). Five cases of IP and NP, respectively, were investigated intraoperatively with OCT and CLSM. Biopsies were taken of the investigated area and were analyzed ex vivo with OCT and CLSM and then underwent HE-staining for standard light microscopy. On OCT images, IP showed the characteristic inverted character of the epithelium, that was thicker with a high degree ...

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    10. Retina Tomography and Optical Coherence Tomography in Eye Diagnostic System

      Retina Tomography and Optical Coherence Tomography in Eye Diagnostic System

      Eye diagnostic, two-step method based on retina color image and Optical Coherence Tomography is presented in this paper. A new robust algorithm, by which various eye diseases can be diagnosed, was implemented as an essential part of the work. The approach comprises two steps. The first one deals with the analysis of retina color image. In this stage, an algorithm was implemented to especially search hard exudates. If the algorithm returns positive, it means at least one hard exudate was found. Moreover, it may return hesitant results in the case of changes that look like hard exudates. During the second ...

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    11. Repeatability and Reproducibility of In Vivo Cone Density Measurements in the Adult Zebrafish Retina

      Repeatability and Reproducibility of In Vivo Cone Density Measurements in the Adult Zebrafish Retina

      Zebrafish ( Danio rerio ) are widely used as an experimental model for a wide range of retinal diseases. Previously, optical coherence tomography (OCT) was introduced for quantitative analysis of the zebrafish cone photoreceptor cell mosaic; however no data exists on the intersession reproducibility or intrasession repeatability of such measurements. We imaged 14 wild-type (WT) fish three times each, with 48 h between each time point. En face images of the UV cone mosaic were generated from the OCT volume scans at each time point. These images were then aligned and the overlapping area cropped for analysis. Using a semiautomated cone-counting algorithm ...

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    12. Normative Retinal Thicknesses in Common Animal Models of Eye Disease Using Spectral Domain Optical Coherence Tomography

      Normative Retinal Thicknesses in Common Animal Models of Eye Disease Using Spectral Domain Optical Coherence Tomography

      Purpose This study demonstrates a standardized approach to measuring retinal thickness (RT) using spectral domain optical coherence tomography (SD-OCT) in commonly used animal models of disease and reports a normative data set for future use. Materials and Methods Twenty normal eyes of 4 adult animal models (5 rats, 5 rabbits, 5 canines, and 5 mini-pigs) were used. Manual measurements were made on the commercially available Heidelberg Spectralis™ SD-OCT to determine the total, inner, and outer retinal thickness (RT) at fixed distances from the optic nerve head (ONH) (1, 2, 3, 4, 5, and 6 mm away) in order to control ...

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    13. Optical coherence tomography to evaluate variance in the extent of carious lesions in depth

      Optical coherence tomography to evaluate variance in the extent of carious lesions in depth

      Evaluation of variance in the extent of carious lesions in depth at smooth surfaces within the same ICDAS code group using optical coherence tomography (OCT) in vitro and in vivo. (1) Verification/validation of OCT to assess non-cavitated caries: 13 human molars with ICDAS code 2 at smooth surfaces were imaged using OCT and light microscopy. Regions of interest (ROI) were categorized according to the depth of carious lesions. Agreement between histology and OCT was determined by unweighted Cohen’s Kappa and Wilcoxon test. (2) Assessment of 133 smooth surfaces using ICDAS and OCT in vitro, 49 surfaces in vivo ...

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    14. Coronary Stent Thrombosis (Book Chapter)

      Coronary Stent Thrombosis (Book Chapter)

      Stent thrombosis is a rare complication of percutaneous coronary intervention and carries a poor prognosis. Recent improvements in stent technology and new antiplatelet therapies have reduced the incidence of stent thrombosis. Coronary stent thrombosis has been defined by the Academic Research Consortium criteria. Four types of thrombosis are defined according to the time of occurrence from stent implantation: acute (<24 h), subacute (<30 days), late (between 1 month and 1 year), and very late (>1 year). Management consists primarily of urgent restoration of antegrade coronary flow. The concurrent management of platelet aggregation is of paramount importance; compliance with the regimen ...

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    15. Upper airway imaging in sleep-disordered breathing

      Upper airway imaging in sleep-disordered breathing

      Our understanding of sleep-disordered breathing has evolved considerably over the past three decades, and clinical techniques of evaluation have progressed tremendously. Myriad imaging techniques are now available for the physician to approach the dynamic features resulting in turbulent airflow, upper airway narrowing or collapse at different levels. Controversy exists in the choice of investigations, probably because the best evaluation should be a combination of different techniques. Physical, radiographic, endoscopic and acoustic evaluations could be integrated to understand the degree and the levels of airway reduction and/or obstruction in a given patient. This review focuses on cost-effective and easily implemented ...

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    16. Novel Automated Approach to Predict the Outcome of Laser Peripheral Iridotomy for Primary Angle Closure Suspect Eyes Using Anterior Segment Optical Coherence Tomography

      Novel Automated Approach to Predict the Outcome of Laser Peripheral Iridotomy for Primary Angle Closure Suspect Eyes Using Anterior Segment Optical Coherence Tomography

      Develop an algorithm to predict the success of laser peripheral iridotomy (LPI) in primary angle closure suspect (PACS), using pre-treatment anterior segment optical coherence tomography (ASOCT) scans. A total of 116 eyes with PACS underwent LPI and time-domain ASOCT scans (temporal and nasal cuts) were performed before and 1 month after LPI. All the post-treatment scans were classified to one of the following categories: (a) both angles open, (b) one of two angles open and (c) both angles closed. After LPI, success is defined as one or more angles changed from close to open. In this proposed method, the pre ...

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    17. Loquat Bruise Detection Using Optical Coherence Tomography Based on Microstructural Parameters

      Loquat Bruise Detection Using Optical Coherence Tomography Based on Microstructural Parameters

      Slight postharvest bruises of loquats remarkably affect the quality and shelf life of the fruits, but they are difficult to identify using visual inspection. Sub-surface structural changes in cells caused by mechanical injury or impact can be detected using spectroscopy-based methods from different angles. Optical coherence tomography (OCT), a non-destructive technology, can acquire cross-sectional images to analyze sub-surface structures of loquats, thus offering the potential to identify fruit bruises. This study proposes an automated OCT image processing method for extracting large cells from loquat images, which involves a series of steps including image denoising, boundary detection, filtering, binarization, segmentation, and ...

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    18. Predictive value of spectral-domain optical coherence tomography features in assessment of visual prognosis in eyes with acute welding arc maculopathy

      Predictive value of spectral-domain optical coherence tomography features in assessment of visual prognosis in eyes with acute welding arc maculopathy

      Objective To observe spectral-domain optical coherence tomography (SD-OCT) features and to determine whether baseline OCT features can be used as predictors of visual acuity outcome in eyes with acute welding arc maculopathy. Methods This retrospective study enrolled twenty-two eyes of eleven subjects with acute welding arc maculopathy. All subjects were evaluated by SD-OCT at baseline and final visit. The involved parameters included best-corrected visual acuity (BCVA), central macular thickness (CMT), the length of ellipsoid zone (EZ) defects, the greatest linear dimension (GLD) of outer retinal lesions, EZ reflectivity and relative EZ reflectivity (defined as the ratio of EZ reflectivity to ...

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    19. Predictors for target lesion microcalcifications in patients with stable coronary artery disease: an optical coherence tomography study

      Predictors for target lesion microcalcifications in patients with stable coronary artery disease: an optical coherence tomography study

      Background The minimal fibrous cap thickness overlying the necrotic lipid core as well as the presence of macrophages are established characteristics of coronary plaque vulnerability. Recently, the presence of microcalcifications has emerged as a novel feature of vulnerable lesions. However, clinical and plaque morphological predictors of microcalcifications are unknown. Methods In patients with stable coronary artery disease, analysis of plaque morphology ( n  = 112) was performed using optical coherence tomography prior to coronary intervention to assess predictors of microcalcifications. Results Microcalcifications were present in 21/112 (18.7%) lesions. Segments with microcalcifications showed a higher total number of calcifications per lesion ...

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    20. Selection of Flow-Diverter Stent Models Using Optical Coherence Tomography and Mathematical Modeling of Hemodynamics

      Selection of Flow-Diverter Stent Models Using Optical Coherence Tomography and Mathematical Modeling of Hemodynamics

      We describe a method for increasing the effectiveness of surgery to position flow-diverter stents into cerebral arteries with aneurysms based on the combined use of mathematical modeling of hemodynamics and compression elastography. Approaches to determining Young's modulus and the Poisson's ratio for phantom of cerebral artery walls on the basis of endoscopic optical coherence tomography data were developed and tested. The applicability of this method was verified using a model of internal carotid artery aneurysm using a mathematical hemodynamic model taking into account the mechanical properties of the cerebral artery wall.

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    21. Extended field imaging using swept-source optical coherence tomography angiography in retinal vein occlusion

      Extended field imaging using swept-source optical coherence tomography angiography in retinal vein occlusion

      Purpose To evaluate the degree of ischemia in eyes with retinal vein occlusion (RVO) using swept-source optical coherence tomography angiography (SS-OCTA) with the extended field imaging (EFI) technique, which extends the area encompassed by SS-OCTA by scanning through trial frames fitted with a +20-diopter lens. Study Design Retrospective observational study. Methods Twenty-three consecutive eyes of 22 patients with RVO underwent 12 × 12 mm SS-OCTA imaging both with and without EFI for determination of extension rate. Two graders blinded to the clinical data evaluated the degree of retinal ischemia in paired EFI-SS-OCTA and fluorescein angiography (FA) images, and the concordance rates ...

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    22. Parafoveal and optic disc vessel density in patients with obstructive sleep apnea syndrome: an optical coherence tomography angiography study

      Parafoveal and optic disc vessel density in patients with obstructive sleep apnea syndrome: an optical coherence tomography angiography study

      Aims To compare optic disc perfusion, radial peripapillary capillaries (RPC) and macular vascular density, between normal subjects and subjects with obstructive sleep apnea syndrome (OSAS) using spectral-domain OCT angiography (OCTA). Methods Sixteen eyes of patients with mild OSAS, 17 eyes with moderate OSAS, 20 eyes with severe OSAS on polygraphy and 28 controls were evaluated with OCTA RT XR Avanti (AngioVue software, Optovue Inc., Fremont, CA). Optic nerve head (ONH), RPC and macular vessel density were measured. Clinical data, visual field parameters, and Spectral Domain OCT evaluation (retinal nerve fiber layer (RNFL) thickness and ganglion cell complex (GCC) thickness) were ...

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      Mentions: Optovue
    23. Preliminary human application of optical coherence tomography for quantification and localization of primordial follicles aimed at effective ovarian tissue transplantation

      Preliminary human application of optical coherence tomography for quantification and localization of primordial follicles aimed at effective ovarian tissue transplantation

      Purpose The purpose of this study was to evaluate the possible clinical application of optical coherence tomography for assessing ovarian reserve in individual specimens of human ovarian tissue for fertility preservation. Methods Ovarian tissue examination by optical coherence tomography was performed before ovarian tissue cryopreservation. Three of the four subjects had hematological disease or cancer, and they faced a threat to their fertility due to impending chemotherapy. One patient underwent ovarian tissue extraction for in vitro activation of dormant follicles as fertility treatment. Results The current full-field optical coherence tomography technique can detect primordial follicles in non-fixed and non-embedded human ...

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    24. Gold nanoshells: Contrast agents for cell imaging by cardiovascular optical coherence tomography

      Gold nanoshells: Contrast agents for cell imaging by cardiovascular optical coherence tomography

      Optical coherence tomography (OCT) has gained considerable attention in interventional cardiovascular medicine and is currently used in clinical settings to assess atherosclerotic lesions and to optimize stent placement. Artery imaging at the cellular level constitutes the first step towards cardiovascular molecular imaging, which represents a major advance in the development of personalized noninvasive therapies. In this work, we demonstrate that cardiovascular OCT can be used to detect individual cells suspended in biocompatible fluids. Importantly, the combination of this catheter-based clinical technique with gold nanoshells (GNSs) as intracellular contrast agents led to a substantial enhancement in the backscattered signal produced by ...

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      Mentions: Fernando Alfonso
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