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    1. Time-domain optical coherence tomography system based on moving-optical-wedge interferometer

      Time-domain optical coherence tomography system based on moving-optical-wedge interferometer

      In this work we present a time-domain optical coherence tomography system based on moving-optical-wedge interferometer. This device has the advantage of suppressing motion artifact. The major problem with such a system is dispersion in the wedge material. We propose an algorithm for compensation of such dispersion. Moreover, we investigate the effect of dispersion in resolution. So, we introduced artificial high dispersion in the wedge material to clarify this effect. Resolution is improved from 10 µm to 5 µm. Thus we can consider dispersion is a bless in improving resolution.

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    2. Glioma cell migration dynamics in brain tissue assessed by multimodal optical imaging

      Glioma cell migration dynamics in brain tissue assessed by multimodal optical imaging

      Glioblastoma is a primary malignant brain tumor characterized by highly infiltrative glioma cells. Vasculature and white matter tracts are considered to be the preferred and fastest routes for glioma invasion through brain tissue. In this study, we systematically quantified the routes and motility of the U251 human glioblastoma cell line in mouse brain slices by multimodal imaging. Specifically, we used polarization-sensitive optical coherence tomography to delineate nerve fiber tracts while confocal fluorescence microscopy was used to image cell migration and brain vasculature. Somewhat surprisingly, we found that in mouse brain slices, U251 glioma cells do not follow white matter tracts ...

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    3. Clinical efficacy of optical coherence tomography to predict the visual outcome after endoscopic endonasal surgery for suprasellar tumors

      Clinical efficacy of optical coherence tomography to predict the visual outcome after endoscopic endonasal surgery for suprasellar tumors

      Objective Prediction of visual outcome following endoscopic endonasal tumor resection still remains a challenge. We investigated the prognostic value of preoperative peripapillary retinal nerve fiber layer (pRNFL) using the optical coherence tomography (OCT) for visual outcome after endoscopic endonasal surgery (EES) for suprasellar tumors. Methods We retrospectively analyzed 122 patients who underwent EES for sellar and suprasellar tumors between January 2016 and January 2018. We retrospectively analyzed the pre- and post-operative relationship between pRNFL thickness and visual outcome, based on the visual acuity (visual acuity score, VAS) and visual field (mean deviation, MD). Results Preoperatively, 216 eyes (mean 94.3 ...

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    4. Diagnostic accuracy of 320-row computed tomography for characterizing coronary atherosclerotic plaques: Comparison with intravascular optical coherence tomography

      Diagnostic accuracy of 320-row computed tomography for characterizing coronary atherosclerotic plaques: Comparison with intravascular optical coherence tomography

      Background/Purpose. This study sought to determine the diagnostic accuracy of 320-row computed tomography (320CT) for characterizing coronary atherosclerotic plaques in comparison with optical coherence tomography (OCT). Methods/Materials. From 32 patients, 42 coronary segments were evaluated and co-registered by both 320CT and OCT. 320CT vulnerable plaque characteristics included low attenuation plaque (LAP) (<30HU), napkin-ring sign (NRS), positive remodeling (PR) and spotty calcification (SC). The presence of macrophage, neovascularization and cholesterol crystals was also determined by OCT. Results Minimal lumen area was 2.78 ± 1.23 mm by OCT and 3.29 ± 1.49 mm by 320CT ( p < 0.001 ...

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    5. Measurement of granule layer thickness in a spouted bed coating process via optical coherence tomography

      Measurement of granule layer thickness in a spouted bed coating process via optical coherence tomography

      In this work a recently developed in-line measurement technique for monitoring of coating thickness was applied to a spray-coating process in a three-dimensional prismatic spouted bed. The layer thickness was quantified with an optical coherence tomography (OCT) sensor positioned in front of the observation window of the process chamber. The time-dependent layer thickness was measured directly and in real-time from the OCT images, with no chemometric calibration being needed. To validate the obtained data, additional off-line OCT measurements were performed with optical particle size measurements and micro–computed tomography (micro-CT). The off-line measurements were conducted with representative samples extracted at ...

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    6. Angiography and optical coherence tomography assessment of the drug-coated balloon ESSENTIAL for the treatment of in-stent restenosis

      Angiography and optical coherence tomography assessment of the drug-coated balloon ESSENTIAL for the treatment of in-stent restenosis

      Objectives This study sought to assess the efficacy of the drug-coated balloon (DCB) ESSENTIAL for the treatment of in-stent restenosis (ISR). Background DCBs have proven a valid therapeutic option for the management of ISR in several clinical trials, yet no class effect can be claimed. Accordingly, every new DCB model has to be individually evaluated through clinical studies. Methods This is a prospective, multicenter study including consecutive patients undergoing percutaneous coronary intervention for ISR with the ESSENTIAL DCB. A 6-month quantitative coronary angiography (QCA)/optical coherence tomography (OCT) follow-up was scheduled. The primary endpoint was OCT-derived in-segment maximal area stenosis ...

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    7. Detection of glaucomatous optic neuropathy with spectral-domain optical coherence tomography: a retrospective training and validation deep-learning analysis

      Detection of glaucomatous optic neuropathy with spectral-domain optical coherence tomography: a retrospective training and validation deep-learning analysis

      Background Spectral-domain optical coherence tomography (SDOCT) can be used to detect glaucomatous optic neuropathy, but human expertise in interpretation of SDOCT is limited. We aimed to develop and validate a three-dimensional (3D) deep-learning system using SDOCT volumes to detect glaucomatous optic neuropathy. Methods We retrospectively collected a dataset including 4877 SDOCT volumes of optic disc cube for training (60%), testing (20%), and primary validation (20%) from electronic medical and research records at the Chinese University of Hong Kong Eye Centre (Hong Kong, China) and the Hong Kong Eye Hospital (Hong Kong, China). Residual network was used to build the 3D ...

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    8. Dynamic Contrast Optical Coherence Tomography reveals laminar microvascular hemodynamics in the mouse neocortex in vivo

      Dynamic Contrast Optical Coherence Tomography reveals laminar microvascular hemodynamics in the mouse neocortex in vivo

      Studies of flow-metabolism coupling often presume that microvessel architecture is a surrogate for blood flow. To test this assumption, we introduce an in vivo Dynamic Contrast Optical Coherence Tomography (DyC-OCT) method to quantify layer-resolved microvascular blood flow and volume across the full depth of the mouse neocortex, where the angioarchitecture has been previously described . First, we cross-validate average DyC-OCT cortical flow against conventional Doppler OCT flow. Next, with laminar DyC-OCT, we discover that layer 4 consistently exhibits the highest microvascular blood flow, approximately two-fold higher than the outer cortical layers. While flow differences between layers are well-explained by microvascular volume ...

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    9. In vitro longitudinal evaluation of enamel wear by cross-polarization optical coherence tomography

      In vitro longitudinal evaluation of enamel wear by cross-polarization optical coherence tomography

      Objectives Enamel thickness determination by Cross-Polarization Optical Coherence Tomography (CP-OCT) is a promising approach for quantitative monitoring of tooth wear progression. This study evaluated the ability of CP-OCT to quantify the thickness of natural enamel before, during and after tooth wear simulation. Materials and Methods Natural, unpolished human dental enamel slabs were submitted to five wear stages (Wear 1: to level the surfaces; Wear 2 to Wear 5: 0.05 ± 0.02 mm reduction each) simulated by an automatic grinding/polishing machine. Enamel thickness was evaluated with CP-OCT and a gold-standard method (micro-CT) at baseline and after every wear stage ...

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    10. Chronic chiasmal compression and persistent visual field defect without detectable changes in optical coherence tomography of the macular ganglion cell complex

      Chronic chiasmal compression and persistent visual field defect without detectable changes in optical coherence tomography of the macular ganglion cell complex

      Purpose Optical coherence tomography (OCT) of the retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC) are important in the ophthalmological evaluation of patients with sellar masses. Changes in OCT of the RNFL and macular GCC often precede visual field changes in patients with chronic chiasmal compression. OCT of the macular GCC has been shown to have better correlation with visual function and allow for even earlier detection of compression of the anterior visual pathways. We present a case of a chronic visual field defect from a pituitary adenoma with largely normal OCT parameters and only subtle changes ...

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    11. OCT in the diagnosis of head and neck pre-cancerous and cancerous cutaneous lesions: An immediate ex vivo study

      OCT in the diagnosis of head and neck pre-cancerous and cancerous cutaneous lesions: An immediate ex vivo study

      Background Optical coherence tomography (OCT) has been shown to reliably identify skin changes with the combined advantage of resolution and penetration depth. The objective of this study was to assess the accuracy of OCT in diagnosing various skin pathologies, using pre-set diagnostic criteria, by two reviewers blinded to the actual diagnosis. Material and methods This immediate ex-vivo study included skin specimens from 103 patients with suspicious skin lesions. In total, 110 lesions were scanned using OCT immediately following surgical resection. Two experienced OCT reviewers assessed these OCT diagnostic parameters blindly at two different intervals based on the parameters of the ...

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    12. Full-range Fourier-domain optical coherence tomography based on Mach–Zehnder interferometer

      Full-range Fourier-domain optical coherence tomography based on Mach–Zehnder interferometer

      We proposed a full-range Fourier-domain optical coherence tomography (FR-FDOCT) based on a Mach–Zehnder interferometer with a tilted mirror which could generate a series of accurate phase-delay interference signals simultaneously. The FR-FDOCT is capable of acquiring artifact-free images by the construction of both amplitude and phase of the interferogram from multiple sets of phase-delay signals. The Mach–Zehnder interferometer make the reference arm became single-way optical path which is more convenient to adjust the reference beam than the return-way optical path (which means the incident and reflected beams use the same optical path) of traditional systems. A series of phase-delay ...

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    13. Fully Automated Postlumpectomy Breast Margin Assessment Utilizing Convolutional Neural Network Based Optical Coherence Tomography Image Classification Method

      Fully Automated Postlumpectomy Breast Margin Assessment Utilizing Convolutional Neural Network Based Optical Coherence Tomography Image Classification Method

      Background The purpose of this study was to develop a deep learning classification approach to distinguish cancerous from noncancerous regions within optical coherence tomography (OCT) images of breast tissue for potential use in an intraoperative setting for margin assessment. Methods A custom ultrahigh-resolution OCT (UHR-OCT) system with an axial resolution of 2.7 μm and a lateral resolution of 5.5 μm was used in this study. The algorithm used an A-scan-based classification scheme and the convolutional neural network (CNN) was implemented using an 11-layer architecture consisting of serial 3 × 3 convolution kernels. Four tissue types were classified, including adipose ...

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    14. Optical coherence tomography angiography in best vitelliform macular dystrophy

      Optical coherence tomography angiography in best vitelliform macular dystrophy

      Purpose To report best vitelliform macular dystrophy (BVMD) with an intriguing pattern of vascular flow on optical coherence tomography angiography (OCTA). Methods Four eyes of two patients with BVMD were evaluated. Complete ophthalmic examination including best corrected visual acuity (BCVA), spectral domain optical coherence tomography (SD-OCT), and OCTA were performed. Diagnosis was confirmed by electroretinography (ERG) and electrooculography (EOG) testing. Results All eyes had the electrophysiologic confirmation of the BVMD. The first patient was 35 years old with BCVA of 20/20 and pseudohypopyon stage macular lesion in right eye (RE) and BCVA of 20/32 and vitelliruptive stage macular ...

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    15. Ocular coherence tomography for the diagnosis of Descemet's detachment after deep sclerectomy and resolution after intracameral air injection

      Ocular coherence tomography for the diagnosis of Descemet's detachment after deep sclerectomy and resolution after intracameral air injection

      Purpose to report the use of optical coherence tomography (OCT) in a case of Descemet's membrane detachment (DMD) secondary to a nonpenetrating deep sclerectomy (NPDS) and the efficacy of intracameral air injection for management. Observations DMD was identified by anterior segment OCT (AS-OCT) in a 61-year-old male patient who was blind in the right eye and had advanced open angle glaucoma. This patient underwent NPDS in the left eye and developed localized corneal edema postoperatively. Air was injected into the anterior chamber resulting in reattachment of Descemet's membrane and resolution of corneal edema. Conclusions and Importance: This case ...

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    16. Assessment of Vascular Patency and Inflammation with Intravascular Optical Coherence Tomography in Patients with Superficial Femoral Artery Disease Treated with Zilver PTX Stents

      Assessment of Vascular Patency and Inflammation with Intravascular Optical Coherence Tomography in Patients with Superficial Femoral Artery Disease Treated with Zilver PTX Stents

      Purpose Zilver PTX nitinol self-expanding drug-eluting stent with paclitaxel coating is effective for treatment of superficial femoral artery (SFA) disease. However, as with any stent, it induces a measure of vascular inflammatory response. The current clinical trial (NCT02734836) aimed to assess vascular patency, remodeling, and inflammatory markers with intravascular optical coherence tomography (OCT) in patients with SFA disease treated with Zilver PTX stents. Methods Serial OCT examinations were performed in 13 patients at baseline and 12-month follow-up. Variables evaluated included neointimal area, luminal narrowing, thrombus area, stent expansion as well as measures of inflammation including, peri-strut low-intensity area (PLIA), macrophage ...

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    17. Effects of panretinal photocoagulation on retinal vasculature and foveal avascular zone in diabetic retinopathy using optical coherence tomography angiography: A pilot study

      Effects of panretinal photocoagulation on retinal vasculature and foveal avascular zone in diabetic retinopathy using optical coherence tomography angiography: A pilot study

      Purpose To evaluate the optical coherence tomography angiography (OCTA) parameters in patients with diabetic retinopathy following panretinal photocoagulation (PRP). Methods Eleven eyes of 6 patients with very severe nonproliferative diabetic retinopathy (NPDR) or early proliferative diabetic retinopathy (PDR) were recruited in this prospective interventional pilot study. All patients underwent OCTA imaging at baseline, and choroidal flow, foveal avascular zone (FAZ), retinal thickness, and vascular density were measured at baseline. Three months after treatment, OCTA was repeated, and the alteration in variables was analyzed. Results The FAZ area remained unchanged following treatment, ( P = 0.75). Retinal thickness increased along ( P = 0 ...

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    18. Posterior Ocular Blood Flow in Preeclamptic Patients Evaluated with Optical Coherence Tomography Angiography

      Posterior Ocular Blood Flow in Preeclamptic Patients Evaluated with Optical Coherence Tomography Angiography

      Objective The aim of the present study was to examine the effects of preeclampsia on posterior ocular blood flow through optic coherence tomography angiography (OCTA). Study Design The study included preeclamptic pregnant women (group PPW), healthy pregnant women (group HPW) and control non-pregnant women (group CNPW). The blood flow area of retina, optic nerve head and choriocapillaris were assessed through OCTA. Results Retinal superficial blood flow area (RSBFA) was similar in group PPW, HPW and CNPW (p = 0.101); likewise, there was not any difference in retinal superficial parafoveal vessel density (RSPFD) between the groups (p = 0.685). There was ...

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    19. The Effect of Stent Artefact on Quantification of Plaque Features Using Optical Coherence Tomography (OCT): A Feasibility and Clinical Utility Study

      The Effect of Stent Artefact on Quantification of Plaque Features Using Optical Coherence Tomography (OCT): A Feasibility and Clinical Utility Study

      Background Optical coherence tomography (OCT) can detect detailed plaque features in native coronary arteries. Stent struts cause shadows that partially obscure the vessel wall, but plaque features can still be seen. We investigated the impact of stent artefact on plaque quantification and whether the plaque behind struts is associated with microvascular dysfunction. Methods Patients retrospectively recruited from two centres, underwent OCT pre- and post-stenting on the same vessel segment. Lipid (LA) and calcium (CA) were measured as arcs. Macrophages, microchannels and cholesterol crystals were counted. Subsequently, we determined whether stented plaque features were associated with reduced TIMI flow grade in ...

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    20. In Vivo Characterization of the Deformation of the Human Optic Nerve Head Using Optical Coherence Tomography and Digital Volume Correlation

      In Vivo Characterization of the Deformation of the Human Optic Nerve Head Using Optical Coherence Tomography and Digital Volume Correlation

      We developed a method to measure the 3-dimensional (3D) strain field in the optic nerve head (ONH) in vivo between two intraocular pressures (IOP). Radial optical coherence tomography (OCT) scans were taken of the ONH of 5 eyes from 5 glaucoma patients before and after IOP-lowering surgery and from 5 eyes from 3 glaucoma suspect patients before and after raising IOP by wearing tight-fitting swimming goggles. Scans taken at higher and lower IOP were compared using a custom digital volume correlation (DVC) algorithm to calculate strains in the anterior lamina cribrosa (ALC), retina, and choroid. Changes in anterior lamina depth ...

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    21. How to Measure Coating Thickness of Tablets: Method Comparison of Optical Coherence Tomography, Near-infrared Spectroscopy and Weight-, Height- and Diameter Gain

      How to Measure Coating Thickness of Tablets: Method Comparison of Optical Coherence Tomography, Near-infrared Spectroscopy and Weight-, Height- and Diameter Gain

      Film coating of pharmaceutical dosage forms, such as tablets and pellets, can be used to tailor the drug release profile. With that regard, a uniform coating thickness of a single tablet (intra-tablet), all tablets (inter-tablet) and subsequent batches (inter-batch) is crucial. We present a method comparison between in-line (optical coherence tomography and near-infrared spectroscopy) and well-established off-line (height-, weight- and diameter-gain) approaches to determining the coating thickness of tablets. We used single tablets drawn during a commercial coating process. Comparing the low intra- and high inter-tablet coating variability indicated that the tablets had a broad distribution of spray zone passes ...

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    22. Severe acute stent malapposition follow-up: 3-month and 12-month serial quantitative analyses by optical coherence tomography

      Severe acute stent malapposition follow-up: 3-month and 12-month serial quantitative analyses by optical coherence tomography

      Background Optical coherence tomography (OCT) was used to assess serial changes in severe acute stent malapposition (ASM) after drug-eluting stent (DES) implantation. Methods The maximal depth and axial lengths of ASM after DES implantation were serially quantified at percutaneous coronary intervention (PCI), and at 3 and 12-month follow-up, for 100 lesions in 96 patients. Severe ASM was defined as a maximal malapposed depth ≥400 μm or maximal malapposed axial length ≥1 mm. Results Of the 100 lesions, 23 lesions (23%) had a severe ASM depth at PCI. At 3 months, the maximal depth decreased to <400 μm in 12 of ...

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    23. Diagnostic accuracy of spectral domain optical coherence tomography circumpapillary, optic nerve head and macular parameters in the detection of perimetric glaucoma

      Diagnostic accuracy of spectral domain optical coherence tomography circumpapillary, optic nerve head and macular parameters in the detection of perimetric glaucoma

      Objective To evaluate the diagnostic accuracy of circumpapillary retinal nerve fibre layer (cRNFL), optic nerve head and macular parameters for the detection of glaucoma using Heidelberg Spectralis optical coherence tomography (OCT). Design Cross-sectional study. Participants Participants of the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA) with a vertical cup to disc ratio (VCDR) ≥0.7 and/or VCDR asymmetry ≥0.2 and/or vertical neuroretinal rim ratio (NRRR) ≤0.1 and/or intraocular pressure (IOP) ≥ 25 mmHg were invited to attend the study. Methods Participants underwent clinical examination by a masked glaucoma expert and full-threshold visual field ...

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