1. All Articles

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    1. Are the findings of optical coherence tomography sufficient for the evaluation of the safety and efficacy of the next generation of drug eluting stents

      Are the findings of optical coherence tomography sufficient for the evaluation of the safety and efficacy of the next generation of drug eluting stents

      The cr8 stent is a next generation drug eluting stent (DES) with a polymer free abluminal reservoir drug release system. It uses an organic fatty acid permeation enhancer and a carbon surface to increase biocompatibility. The fatty acid enhancer may have beneficial effect in improving drug delivery in diabetic patient where neointimal hyperplasia is particularly problematic[1]. These types of design features are exciting new developments and may provide novel strategies for improving the safety and efficacy of the next generation of coronary stents.

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    2. Optical Coherence Tomography Imaging of Presumed Sarcoid Retinal and Optic Nerve Nodules

      Optical Coherence Tomography Imaging of Presumed Sarcoid Retinal and Optic Nerve Nodules

      Purpose : To characterize nodular lesions of the retina and optic nerve with spectral-domain optical coherence tomography (SD-OCT) in patients with sarcoidosis. Methods : This is a retrospective series of 6 eyes from 5 patients with an established diagnosis of sarcoidosis, with clinically detected nodules of the optic nerve or retina. All lesions were imaged with fundus photography and SD-OCT on presentation, and followed with serial imaging after treatment with corticosteroids and/or immunomodulatory therapy. Results : Spectral OCT through the lesions revealed nodular hyperreflective processes obscuring the retinal layers or optic cup, with local structural changes, including subretinal and intraretinal fluid. After ...

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    3. Insights into the spatial distribution of lipid-rich plaques in relation to coronary artery bifurcations: an in-vivo optical coherence tomography study

      Insights into the spatial distribution of lipid-rich plaques in relation to coronary artery bifurcations: an in-vivo optical coherence tomography study

      Objectives: The aim of this study was to investigate the spatial location of vulnerable plaques at coronary artery bifurcations using frequency domain-optical coherence tomography. Background: In-vivo data on geometric location of vulnerable plaques in relation to coronary bifurcation are limited. Materials and methods: A total of 40 patients with left anterior descending artery bifurcation were studied. Plaque characteristics in five regions in relation to a side branch were compared: opposite flow divider (OFD); bifurcation site (BF); main branch side proximal (MBP); side branch side proximal (SBP); and flow divider (FD). Frequency domain-optical coherence tomography was used for plaque characterization. Results ...

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    4. Optical coherence tomography imaging of inoperable chronic thromboembolic pulmonary hypertension treated with refined balloon pulmonary angioplasty

      Optical coherence tomography imaging of inoperable chronic  thromboembolic pulmonary hypertension treated with refined balloon  pulmonary angioplasty

      Chronic thromboembolic pulmonary hypertension (CTEPH) usually results from the chronic obstruction of the pulmonary arteries by unresolved thromboemboli following acute pulmonary embolism (PE). Surgical pulmonary endarterectomy is the first-line therapy in CTEPH, however some patients are inoperable due to high perioperative risk or distal localization of thrombi. Balloon pulmonary angioplasty (BPA), a new emerging therapy, with growing evidence has been adopted in this group of patients [1]. Recently refined BPA has been described with use of new imaging modalities, which markedly improved both BPA efficacy and safety [2,3]. Optical coherence tomography (OCT) is a novel, promising tool and was ...

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    5. Optical coherence tomography and confocal microscopy following 3 different protocols of corneal collagen-crosslinking in keratoconus.

      Optical coherence tomography and confocal microscopy following 3 different protocols of corneal collagen-crosslinking in keratoconus.

      Purpose: To compare the efficacy and early morphological changes in the cornea following conventional (C-CXL), transepithelial by iontophoresis (I-CXL), and accelerated collagen cross-linking (A-CXL) in keratoconus. Methods: 45 eyes of 45 patients with progressive keratoconus who underwent corneal collagen crosslinking (CXL) were divided into 3 groups: C-CXL (n=15), A-CXL (n=15) and I-CXL (n=15). Patients were examined before surgery and at 1-month, 3-month, and 6-month intervals following surgery. Density of corneal sub-basal nerves, anterior and posterior keratocytes, corneal endothelium, demarcation line depth and maximal simulated keratometry values (Kmax) were all assessed. Results: Compared with preoperative values, the mean ...

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    6. Lipid-rich plaque in possible coronary sequelae of Kawasaki disease detected by optical frequency domain imaging

      Lipid-rich plaque in possible coronary sequelae of Kawasaki disease detected by optical frequency domain imaging

      Potential risk for early development of atherosclerosis in patients with antecedent- Kawasaki disease (KD) is now attracting more attention. A 47-year-old man was admitted to our hospital because of calcification exclusively in the proximal segment of left anterior descending coronary artery (LAD) on chest CT. Coronary CT revealed a severe stenosis at the inlet of the aneurysm with eggshell-like calcification in the proximal LAD, highly suspecting the presence of coronary sequelae of KD. During the rotational atherectomy-based interventional procedure, optical frequency domain imaging, a new generation of optical coherence tomography, clearly depicted lipid deposition in the culprit lesion.

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    7. Peripapillary rat sclera investigated in vivo with polarization sensitive optical coherence tomography

      Peripapillary rat sclera investigated in vivo with polarization sensitive optical coherence tomography

      Purpose: To demonstrate polarization sensitive (PS) optical coherence tomography (OCT) for non-invasive, volumetric, and quantitative imaging of the birefringent properties of the peripapillary rat sclera. To compare the findings in PS-OCT images to state-of-the-art histomorphometric analysis of the same tissues. Methods: A high-speed PS-OCT prototype operating at 840 nm was modified for imaging the rat eye. Densely sampled PS-OCT raster scans covering an area of ~1.5 mm × 1.5 mm centered at the papilla were acquired in the eyes of anesthetized, male Sprague Dawley rats. Cross-sectional PS-OCT images were computed and fundus maps displaying the birefringent properties of the ...

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    8. Graphene Sensors Stimulate Neurons Optically And Electronically

      Graphene Sensors Stimulate Neurons Optically And Electronically

      While electrical sensing is a mainstay of neurological studies, optical methods have recently started to become more prevalent. A new sensor system from DARPA now allows both modalities to be used together, for greater insights into neural structure and function. Electrical impulses are the primary way that neural cells communicate. Historically, electrical studies have enabled the evaluation of neural cell communication. Generally, the understanding of neural cells that was gained by studying electrical impulses was garnered through correlation studies, so a direct link was not possible to prove relationships between neural cell electrical activity and behavior. Recently, the development of ...

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    9. Enhanced depth imaging optical coherence tomography of congenital cavitary optic disc anomaly (CODA)

      Enhanced depth imaging optical coherence tomography of congenital cavitary optic disc anomaly (CODA)

      Aim To report the finding of extension of the 4th hyper-reflective band and retinal tissue into the optic disc in patients with cavitary optic disc anomalies (CODAs). Methods In this observational study, 10 patients (18 eyes) with sporadic or autosomal dominant CODA were evaluated with enhanced depth imaging optical coherence tomography (EDI-OCT) and colour fundus images for the presence of 4th hyper-reflective band extension into the optic disc. Results Of 10 CODA patients (18 eyes), five patients (8 eyes) showed a definite 4th hyper-reflective band (presumed retinal pigment epithelium (RPE)) extension into the optic disc. In these five patients (seven ...

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    10. Spectral-Domain Optical Coherence Tomography of Sympathetic Ophthalmia With Dalen-Fuchs Nodules

      Spectral-Domain Optical Coherence Tomography of Sympathetic Ophthalmia With Dalen-Fuchs Nodules

      The authors present a case of sympathetic ophthalmia with Dalen–Fuchs nodules visualized with spectral-domain optical coherence tomography (SD-OCT). An 84-year-old man presented with floaters and decreased vision 25 years after penetrating trauma to the fellow eye. Examination revealed vitritis and subretinal lesions consistent with Dalen–Fuchs nodules. He was diagnosed with sympathetic ophthalmia after a negative systemic work-up. SD-OCT revealed hyper-reflective lesions at the level of the retinal pigment epithelium with disruption of the inner segment/outer segment (IS/OS) junction. Treatment resulted in clinical improvement and disappearance of Dalen–Fuchs nodules on SD-OCT; however, photoreceptor and retinal pigment ...

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    11. Platform to investigate aqueous outflow system structure and pressure-dependent motion using high-resolution spectral domain optical coherence tomography

      Platform to investigate aqueous outflow system structure and pressure-dependent motion using high-resolution spectral domain optical coherence tomography

      The aqueous outflow system (AOS) is responsible for maintaining normal intraocular pressure (IOP) in the eye. Structures of the AOS have an active role in regulating IOP in healthy eyes and these structures become abnormal in the eyes with glaucoma. We describe a newly developed system platform to obtain high-resolution images of the AOS structures. By incorporating spectral domain optical coherence tomography (SD-OCT), the platform allows us to systematically control, image, and quantitate the responses of AOS tissue to pressure with a millisecond resolution of pulsed flow. We use SD-OCT to image radial limbal segments from the surface of the ...

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    12. Anisotropic polyvinyl alcohol hydrogel phantom for shear wave elastography in fibrous biological soft tissue: a multimodality characterization

      Anisotropic polyvinyl alcohol hydrogel phantom for shear wave elastography in fibrous biological soft tissue: a multimodality characterization

      Shear wave elastography imaging techniques provide quantitative measurement of soft tissues elastic properties. Tendons, muscles and cerebral tissues are composed of fibers, which induce a strong anisotropic effect on the mechanical behavior. Currently, these tissues cannot be accurately represented by existing elastography phantoms. Recently, a novel approach for orthotropic hydrogel mimicking soft tissues has been developed (Millon et al 2006 J. Biomed. Mater. Res. B 305–11). The mechanical anisotropy is induced in a polyvinyl alcohol (PVA) cryogel by stretching the physical crosslinks of the polymeric chains while undergoing freeze/thaw cycles. In the present study we propose an original ...

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    13. Comparison of optical coherence tomography and histopathology in quantitative assessment of goat talus articular cartilage

      Comparison of optical coherence tomography and histopathology in quantitative assessment of goat talus articular cartilage

      Background and purpose — Optical coherence tomography (OCT) is a light-based imaging technique suitable for depiction of thin tissue layers such as articular cartilage. Quantification of results and direct comparison with a reference standard is needed to confirm the role of OCT in cartilage evaluation. Materials and methods — Goat talus articular cartilage repair was assessed quantitatively with OCT and compared with histopathology using semi-automated analysis software. Osteochondral defects were created centrally in goat tali with subsequent healing over 24 weeks. After sacrifice, the tali were analyzed using OCT and processed into histopathology slides. Cartilage thickness, repair tissue area, and surface roughness ...

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    14. Comparison of multifocal visual evoked potential, static automated perimetry, and optical coherence tomography findings for assessing visual pathways in patients with pituitary adenomas

      Comparison of multifocal visual evoked potential, static automated perimetry, and optical coherence tomography findings for assessing visual pathways in patients with pituitary adenomas

      Background There have been no studies investigating the correlation between structural [thickness of the retinal nerve fiber layer (RNFL) as determined by optical coherence tomography (OCT)] and functional [Humphrey visual field (HVF) or visual evoked potential (VEP) amplitude] measures of optic nerve integrity in patients with pituitary adenomas (PA). Methods Patients with PAs were recruited between September 2010 and September 2013. OCT, standard automated perimetry (SAP), and multifical VEP (mfVEP) were performed. Agreement between OCT, SAP, and mfVEP values in classifying eyes/quadrants was determined using AC1 statistics. Pearson’s correlation was used to examine relationships between structural and functional ...

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      Mentions: Fudan University
    15. Reproducibility of Spectral-domain Optical Coherence Tomography RNFL Map for Glaucomatous and Fellow Normal Eyes in Unilateral Glaucoma

      Reproducibility of Spectral-domain Optical Coherence Tomography RNFL Map for Glaucomatous and Fellow Normal Eyes in Unilateral Glaucoma

      Purpose: To compare the reproducibility of the optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness map between glaucomatous and fellow normal eyes of unilateral glaucoma patients. Methods: In this prospective case-control study, Cirrus HD-OCT was performed for 79 unilateral glaucoma patients 3 times on the first visit and on 3 subsequent visits within a 2-month period. Test-retest standard deviation (TRT-SD) and tolerance limit based on the 1.645x[square root]2xTRT-SD formula were derived for RNFL thicknesses at the respective superpixels of the RNFL thickness map. Results: The TRT-SDs and tolerance limits of the glaucomatous eyes (TRT-SD: 2 ...

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    16. Identification of vessel wall degradation in ascending thoracic aortic aneurysms with OCT

      Identification of vessel wall degradation in ascending thoracic aortic aneurysms with OCT

      Degradation of the wall of human ascending thoracic aorta has been assessed through Optical Coherence Tomography (OCT). OCT images of the media layer of the aortic wall exhibit micro-structure degradation in case of diseased aortas from aneurysmal vessels. The OCT indicator of degradation depends on the dimension of areas of the media layer where backscattered reflectivity becomes smaller due to a disorder on the morphology of elastin, collagen and smooth muscle cells (SMCs). Efficient pre-processing of the OCT images is required to accurately extract the dimension of degraded areas after an optimized thresholding procedure. OCT results have been validated against ...

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    17. Air etalon facilitated simultaneous measurement of group refractive index and thickness using spectral interferometry

      Air etalon facilitated simultaneous measurement of group refractive index and thickness using spectral interferometry

      A simple method based on air etalons of a transparent cavity is proposed to simultaneously measure the group refractive index and thickness of a transparent optical plate by spectral domain low coherence interferometry. In this method, only a single beam path is needed in contrast to the two beam paths, the reference and sample arms, of the conventional Michelson interferometer. An empty cavity is first constructed in the beam path by two glass plates. Then the transparent plate under test is inserted into the cavity, so that two air gaps are formed in the cavity. A beam of light of ...

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    18. Wide-Field OCT Angiography at 400 KHz Utilizing Spectral Splitting

      Wide-Field OCT Angiography at 400 KHz Utilizing Spectral Splitting

      Optical angiography systems based on optical coherence tomography (OCT) require dense sampling in order to maintain good vascular contrast. We demonstrate a way to gain acquisition speed and spatial sampling by using spectral splitting with a swept source OCT system. This method splits the recorded spectra into two to several subspectra. Using continuous lateral scanning, the lateral sampling is then increased by the same factor. This allows increasing the field of view of OCT angiography, while keeping the same transverse resolution and measurement time. The performance of our method is demonstrated in vivo at different locations of the human retina ...

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    19. A New OCT Finding in Tuberculous Serpiginous-like Choroidopathy

      A New OCT Finding in Tuberculous Serpiginous-like Choroidopathy

      Purpose : To present a case of tubercular serpiginous-like choroiditis (SLC) with previously unreported choroidal findings on enhanced depth imaging OCT (EDI-OCT). Design : Case report. Methods : A 60-year-old female presented with decreased vision. Serpiginous choroidopathy was diagnosed. Laboratory workup revealed an infectious etiology. EDI-OCT revealed previously unreported choroidal findings. Results: Laboratory workup revealed nonreactive Treponema pallidum antibodies and positive QuantiFERON Gold. CT chest showed scars of prior granulomatous disease. OCT with EDI of active lesions demonstrated infiltration of the choroid, elevation of the RPE-Bruch’s membrane complex and focal increase of choroidal thickness. Conclusions: Choroidal infiltration with elevation of the RPE ...

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    20. Wavelength-swept lasers and their application to fiber optic sensors

      Wavelength-swept lasers and their application to fiber optic sensors

      The wavelength swept laser (WSL) is a promising optical source in optical coherence tomography, optical fiber sensor, and optical beat source generation. It is demonstrated by employing a narrowband wavelength-scanning filter, such as a fast rotating polygonal-scanner-filter, a diffraction grating on a galvo-scan mirror, or a fiber Fabry-Perot tunable filter (FFP-TF). In this manuscript, we present our researches on the dynamic fiber-optic sensors. Two kinds of WSLs are used to demonstrate the dynamic measurement in the fiber-optic sensors. One is the WSL using a polygon-scanner-based wavelength filter and the other is the Fourier domain mode-locked (FDML) WSL using a FFP-TF ...

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      Mentions: Min Yong Jeon
    21. Measurement of the blood flow rate and velocity in coronary artery stenosis using intracoronary frequency domain optical coherence tomography: Validation against fractional flow reserve

      Measurement of the blood flow rate and velocity in coronary artery stenosis using intracoronary frequency domain optical coherence tomography: Validation against fractional flow reserve

      Objectives The main objective of this study was to assess the blood flow rate and velocity in coronary artery stenosis using intracoronary frequency domain optical coherence tomography (FD-OCT). A correlation between fractional flow reserve (FFR) and FD-OCT derived blood flow velocity is also included in this study. Methods & Results A total of 20 coronary stenoses in 15 patients were assessed consecutively by quantitative coronary angiography (QCA), FFR and FD-OCT. A percutaneous coronary intervention (PCI) optimization system was used in this study which combines wireless FFR measurement and FD-OCT imaging in one platform. Stenoses were labelled severe if FFR ≤ 0.8 ...

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    22. Shear wave elastography method combining phase-sensitive optical coherence tomography and coded acoustic radiation force

      Shear wave elastography method combining phase-sensitive optical coherence tomography and coded acoustic radiation force

      We combined phase-sensitive optical coherence tomography (PhS-OCT) and acoustic radiation force (ARF) to develop a shear wave elastography (SWE) method that could be used for ophthalmic applications. SWE measures tissue stiffness from the speed of shear waves propagating through tissue. Assessing the elastic properties of the cornea and the intraocular lens can, for example, help the management of refractive surgeries (myopia or presbyopia correction). OCT is a non-contact imaging method easily applicable in vivo that provides micron-scale resolution particularly suitable for characterizing ocular tissues. ARF is commonly used to remotely induce shear waves in tissue by emitting short (∼100 µs ...

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    23. Shear wave elastography of ex vivo human corneas using phase-sensitive optical coherence tomography

      Shear wave elastography of ex vivo human corneas using phase-sensitive optical coherence tomography

      Assessing the biomechanical properties of the cornea can provide clinically valuable information in addition to structural images for better management of pathologies (e.g. glaucoma) or refractive surgeries. OCT provides a micron scale and high sensitivity that are ideal for ophthalmic applications. We propose a shear wave elastography (SWE) method for the cornea based on phase-sensitive optical coherence tomography (PhS-OCT). SWE consists in launching a propagating shear wave in tissues and retrieving tissue elasticity from the shear wave speed. We used a piezo-electric actuator in contact with the cornea to induce shear waves that were then tracked using a PhSOCT ...

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    24. Postdoctoral Position at The Dodd-Walls Centre in New Zealand

      Postdoctoral Position at The Dodd-Walls Centre in New Zealand

      The Dodd-Walls Centre for Photonic and Quantum Technologies is a national Centre of Research Excellence in New Zealand that conducts research in fundamental areas of photonics, quantum optics, ultra-cold atomic and quantum physics, and their applications. We are seeking bright and motivated researchers to join our team in 2015. Postdoctoral fellowships and postgraduate scholarships are offered at our partner universities (Otago, Auckland, Massey, Canterbury and Victoria). We are looking for postdoctoral researchers in the following areas: - Optical Frequency Combs and cavity solitons - THz devices and applications - Optical Sensing including optical coherence tomography - Cavity QED - Non-equilibrium theory of ultra-cold quantum fluids ...

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