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    1. Precision percutaneous coronary intervention: Is optical coherence tomography co‐registration the future?

      Precision percutaneous coronary intervention: Is optical coherence tomography co‐registration the future?

      Integration of angiographic co‐registration (ACR) with optical coherence tomography (OCT) leads to significant changes in PCI strategy. ACR with OCT allows complete integration of all available data‐points to aid decision making. Randomized clinical trials comprehensively evaluating the impact of OCT with ACR to improve clinical outcomes are ongoing.

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    2. Feasibility study of using the dispersion of surface acoustic wave (SAW) impulse for viscoelasticity characterization in tissue mimicking phantoms

      Feasibility study of using the dispersion of surface acoustic wave (SAW) impulse for viscoelasticity characterization in tissue mimicking phantoms

      The aim of this study was to investigate the feasibility of utilizing the phase velocity dispersion of impulse surface acoustic wave (SAW) for viscoelasticity characterization of soft materials. The focused ultrasound transducer and the phase sensitive optical coherence tomography (PhS‐OCT) were applied as the impulse SAW inducer and tracker respectively. Three types of liquid‐paraffin‐based cream‐in‐agar phantoms were tested. Phase velocity dispersion curve was extracted using a Fourier transform based phase velocity analysis algorithm. Viscoelastic parameters were obtained by fitting the dispersion curve of SAW into Rayleigh wave dispersion equation. The estimated viscoelasticity was compared with ...

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    3. Acne vulgaris severity graded by in vivo reflectance confocal microscopy and optical coherence tomography

      Acne vulgaris severity graded by in vivo reflectance confocal microscopy and optical coherence tomography

      Introduction Acne is an inflammatory disease of the pilosebaceous unit, which can be investigated in vivo using reflectance confocal microscopy (RCM) and optical coherence tomography (OCT). Objectives By means of RCM and OCT to identify morphological characteristics of acne that may be associated with clinical acne severity. Methods Patients with mild to moderate facial acne ( n  = 14, Investigators Global Assessment scale, IGA 1–3), and healthy participants ( n  = 7, IGA 0) were included in this explorative study. A total of 108 RCM image blocks and 54 OCT scans (each RCM and OCT image measuring 6 × 6 mm) were captured from ...

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      Mentions: Mette Mogensen
    4. Optical coherence tomography and scleral contact lenses: clinical and research applications

      Optical coherence tomography and scleral contact lenses: clinical and research applications

      Anterior segment optical coherence tomography (OCT) provides a wealth of opportunities for modern contact lens practice. OCT imaging has numerous clinical and research applications related to the tear film, cornea, conjunctiva, sclera and ocular adnexae, in addition to soft, rigid, and hybrid contact lenses. This review summarises the potential use of OCT imaging in modern scleral contact lens practice including initial lens selection, assessing the scleral contact lens fit with respect to the cornea and sclera, and accurately quantifying the ocular response to lens wear. Recent advances in the understanding of anterior segment metrics including scleral thickness, curvature, toricity, and ...

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    5. 1.7 micron optical coherence tomography for vaginal tissue characterization in vivo

      1.7 micron optical coherence tomography for vaginal tissue characterization in vivo

      Objectives Optical coherence tomography (OCT) can noninvasively visualize in vivo tissue microstructure with high spatial resolution that approaches the histologic level. Currently, OCT studies in gynecology are few and limited to a conventional 1.3 μm center wavelength swept light source which provides high spatial resolution but limited penetration depth. Here, we present a novel endoscopic OCT system with improved penetration depth and high resolution. Methods A novel endoscopic OCT system was developed based on a 1.7 µm swept source laser, which is capable of deeper tissue penetration due to its longer wavelength. To evaluate the performance of system ...

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    6. Optical palpation for the visualization of tumor in human breast tissue

      Optical palpation for the visualization of tumor in human breast tissue

      Accurate and effective removal of tumor in one operation is an important goal of breast‐conserving surgery. However, it is not always achieved. Surgeons often utilize manual palpation to assess the surgical margin and/or the breast cavity. Manual palpation, however, is subjective and has relatively low‐resolution. Here, we investigate a tactile imaging technique, optical palpation, for the visualization of tumor. Optical palpation generates maps of the stress at the surface of tissue under static preload compression. Stress is evaluated by measuring the deformation of a contacting thin compliant layer with known mechanical properties using optical coherence tomography. In ...

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    7. Upper airway reconstruction using long‐range optical coherence tomography: Effects of airway curvature on airflow resistance

      Upper airway reconstruction using long‐range optical coherence tomography: Effects of airway curvature on airflow resistance

      Objectives Adenotonsillectomy (AT) is commonly used to treat upper airway obstruction in children, but selection of patients who will benefit most from AT is challenging. The need for diagnostic evaluation tools without sedation, radiation, or high costs has motivated the development of long‐range optical coherence tomography (LR‐OCT), providing real‐time cross‐sectional airway imaging during endoscopy. Since the endoscope channel location is not tracked in conventional LR‐OCT, airway curvature must be estimated and may affect predicted airway resistance. The study objective was to assess effects of three realistic airway curvatures on predicted airway resistance using computational fluid ...

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    8. Subtle changes in diabetic retinas localised in 3D using OCT

      Subtle changes in diabetic retinas localised in 3D using OCT

      Purpose To detect and localise subtle changes in retinas of diabetic patients who clinically have no diabetic retinopathy (DR) or non‐proliferative DR (NPDR) as compared to age‐ and sex‐ matched controls. Spectral Domain Optical Coherence Tomography (SD‐OCT) and software to examine all retinal layers, including deeper layers, were used to quantify foveal avascular zone size and inner and outer retinal layer thicknesses, as well as to detect axial location of prominent lesions. Methods Diabetic subjects, 19 total with 16 having no DR and three having non‐proliferative retinopathy, were matched with 19 controls with respect to age and ...

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    9. Impact and trends of intravascular imaging in diagnostic coronary angiography and percutaneous coronary intervention in inpatients in the United States

      Impact and trends of intravascular imaging in diagnostic coronary angiography and percutaneous coronary intervention in inpatients in the United States

      Background Intravascular imaging with intravascular ultrasound (IVUS) and optical coherence tomography (OCT) is an important adjunct to invasive coronary angiography. Objectives The primary objective was to examine the frequency of intravascular coronary imaging, trends in imaging use, and outcomes of patients undergoing angiography and/or percutaneous coronary intervention (PCI) in the United States. Methods Adult patients ≥18 years of age undergoing in‐hospital cardiac catheterization from January 2004 to December 2014 were identified from the National Inpatient Sample (NIS). International Classification of Diseases, Ninth Revision (ICD‐9) diagnosis and procedure codes were used to identify IVUS and OCT use during ...

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    10. Quantitative depolarization measurements for fiber‐based polarization‐sensitive optical frequency domain imaging of the retinal pigment epithelium

      Quantitative depolarization measurements for fiber‐based polarization‐sensitive optical frequency domain imaging of the retinal pigment epithelium

      A full quantitative evaluation of the depolarization of light may serve to assess concentrations of depolarizing particles in the retinal pigment epithelium and to investigate their role in retinal diseases in the human eye. Optical coherence tomography (OCT) and optical frequency domain imaging (OFDI) use spatial incoherent averaging to compute depolarization. Depolarization depends on accurate measurements of the polarization states at the receiver but also on the polarization state incident upon and within the tissue. Neglecting this dependence can result in artifacts and renders depolarization measurements vulnerable to birefringence in the system and in the sample. In this work, we ...

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    11. Handheld multi‐modal imaging for point‐of‐care skin diagnosis based on akinetic integrated optics optical coherence tomography

      Handheld multi‐modal imaging for point‐of‐care skin diagnosis based on akinetic integrated optics optical coherence tomography

      A handheld skin imaging system with joint optical coherence tomography (OCT) at 1300 nm and digital epiluminescence microscopy (EM) is presented. The two modalities are physically co‐registered in a common‐path configuration. The instrument is enabled by a dedicated planar lightwave circuit with a footprint of only 1.1 x 19.5 mm 2 that provides akinetic axial OCT scanning at speeds up to 24 kHz. Lateral scanning is implemented through a low‐voltage MEMS mirror packaged with the axial scanner in a hermetic butterfly module. The OCT system, with a volume of only 80 x 27 x 14 ...

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    12. Optical coherence tomography‐based angiography device with real‐time angiography B‐scans visualization and hand‐held probe for everyday clinical use

      Optical coherence tomography‐based angiography device with real‐time angiography B‐scans visualization and hand‐held probe for everyday clinical use

      This work is dedicated to the development of the OCT system with angiography for everyday clinical use. Two major problems were solved during the development: compensation of specific natural tissue displacements, induced by contact scanning mode and physiological motion of patients (eg, respiratory and cardiac motions) and online visualization of vessel cross‐sections to provide feedback for the system operator.

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    13. Label‐free volumetric imaging of conjunctival collecting lymphatics ex vivo by optical coherence tomography lymphangiography

      Label‐free volumetric imaging of conjunctival collecting lymphatics ex vivo by optical coherence tomography lymphangiography

      We employ optical coherence tomography (OCT) and optical coherence microscopy (OCM) to study conjunctival lymphatics in porcine eyes ex vivo . This study is a precursor to the development of in vivo imaging of the collecting lymphatics for potentially guiding and monitoring glaucoma filtration surgery. OCT scans at 1300 nm and higher‐resolution OCM scans at 785 nm reveal the lymphatic vessels via their optical transparency. Equivalent signal characteristics are also observed from blood vessels largely free of blood (and devoid of flow) in the ex vivo conjunctiva. In our lymphangiography, vessel networks were segmented by compensating the depth attenuation in ...

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    14. Findings of OCT‐angiography compared to fluorescein and indocyanine green angiography in central serous chorioretinopathy

      Findings of OCT‐angiography compared to fluorescein and indocyanine green angiography in central serous chorioretinopathy

      Purpose The present study analyzed the appearances of optical coherence tomography angiography (OCTA) in patients with central serous chorioretinopathy (CSC) based on fluorescein angiography (FA) and indocyanine green angiography (ICGA). Method In the current case series, 54 eyes of 50 patients diagnosed as CSC were evaluated retrospectively. OCTA, FA, and ICGA were performed on each patient. Two trained observers examined the OCTA images independently to confirm and compare the choriocapillary appearance with that on FA/ICGA. Also, the leakage of vessels on FA, perfusion of choroidal blood flow on ICGA, blood flow density, and vascular morphology on OCTA, as well ...

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    15. Argon plasma coagulation of actinic keratoses imaged by optical coherence tomography: an in‐vivo study indicating a possible lesion‐directed treatment

      Argon plasma coagulation of actinic keratoses imaged by optical coherence tomography: an in‐vivo study indicating a possible lesion‐directed treatment

      Actinic keratoses (AKs) can progress into invasive squamous cell carcinoma and thus may become a life threatening disease. Argon plasma coagulation (APC) might complement the therapeutic armamentarium in particular for AK lesions. However, there is no data on APC induced micromorphological changes following the treatment of AKs. We aimed to determine in‐vivo APC induced effects on the epidermis and dermo‐epidermal junction zone (DEJ) in AK lesions. We performed APC in 108 AKs using the spray mode with a power setting of 15W and a flow rate of 2.0 L/min. Before and after the intervention, optical coherence ...

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      Mentions: Thilo Gambichler
    16. Automated three‐dimensional cell counting method for grading uveitis of rodent eye in vivo with optical coherence tomography

      Automated three‐dimensional cell counting method for grading uveitis of rodent eye in vivo with optical coherence tomography

      In preclinical vision research, cell grading in small animal models is essential for the quantitative evaluation of intraocular inflammation. Here, we present a new and practical optical coherence tomography (OCT) image analysis method for the automated detection and counting of aqueous cells in the anterior chamber (AC) of a rodent model of uveitis. Anterior segment OCT images are acquired with a 100 kHz swept‐source OCT system. The proposed method consists of 2 steps. In the first step, we first despeckle and binarize each OCT image. After removing AS structures in the binary image, we then apply area thresholding to ...

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    17. Quantitative evaluation of optical coherence tomography angiography images of diabetic retinopathy eyes before and after removal of projection artifacts

      Quantitative evaluation of optical coherence tomography angiography images of diabetic retinopathy eyes before and after removal of projection artifacts

      Projection artifacts (PAs) affect the quantification of vascular parameters in the deep layer optical coherence tomography (OCT) angiography image. This study eliminated PA and quantified its effect on imaging. 53 eyes (30 subjects) of normal Indian subjects and 113 eyes (92 patients) of type 2 diabetes mellitus with retinopathy (DR) underwent imaging with a scan area of 3 mm × 3 mm. In this study, a normalized cross‐correlation between superficial and deep layer was used to remove PA in deep layer. Local fractal analysis was done to compute vascular parameters such as foveal avascular zone area (mm 2 ), vessel density ...

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    18. Multiple enface image averaging for enhanced optical coherence tomography angiography imaging

      Multiple enface image averaging for enhanced optical coherence tomography angiography imaging

      Purpose To investigate the effect of multiple enface image averaging on image quality of the optical coherence tomography angiography (OCTA). Methods Twenty‐one normal volunteers were enrolled in this study. For each subject, one eye was imaged with 3 × 3 mm scan protocol, and another eye was imaged with the 6 × 6 mm scan protocol centred on the fovea using the ZEISS Angioplex™ spectral‐domain OCTA device. Eyes were repeatedly imaged to obtain nine OCTA cube scan sets, and nine superficial capillary plexus (SCP) and deep capillary plexus (DCP) were individually averaged after registration. Results Eighteen eyes with a 3 ...

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    19. Imaging technique for the diagnosis of onychomatricoma

      Imaging technique for the diagnosis of onychomatricoma

      Onychomatricoma is a rare tumour that derives from the nail matrix and grows within the nail plate. The clinical presentation can mimic many other tumors and conditions and surgical biopsy and histopathological examination are necessary to confirm the diagnosis. Since nail surgery is a painful experience for the patient and sometimes can leave permanent onychodistrophy, more precise preoperative diagnosis is needed to distinguish onychomatricoma from other nail diseases more accurately and to limit surgical interventions. The objective of this study was to evaluate current literature on imaging techniques for the diagnosis of onychomatricoma in order to understand how this technology ...

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    20. Mechanical spectroscopy and imaging of skin components in vivo: Assignment of the observed moduli

      Mechanical spectroscopy and imaging of skin components in vivo: Assignment of the observed moduli

      Background The need to quantitatively identify the composition and organization of the macromolecular components of skin, skin lesions, scars, tumors, extracellular matrices (ECMs), and wound tissue has been a goal of researchers for many decades. A variety of studies have been recently reported applying optical coherence tomography (OCT) to image skin and cutaneous lesions. Materials and Methods This article describes the use of vibrational OCT to image and noninvasively characterize the macromolecular components of the ECM of skin. Results We report that the major macromolecular components of skin and scar can be identified noninvasively by their characteristic moduli calculated from ...

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    21. Measurement of Flow‐Mediated Dilation of Mouse Femoral Artery in vivo by Optical Coherence Tomography

      Measurement of Flow‐Mediated Dilation of Mouse Femoral Artery in vivo by Optical Coherence Tomography

      Flow‐mediated vasodilation (FMD) is used for assessment of vascular endothelial function in humans as a predictor of cardiovascular events. It has been challenging to carry it on preclinical murine models due to the diminutive size of the femoral artery. Here, we present a new approach to accurately measure the blood velocity and femoral artery diameters of mice by acquiring Doppler optical coherence tomography (DOCT) and optical coherence tomography angiography (OCTA) continuously within one single experimental scanning protocol. Using the high precision three‐dimensional imaging and new velocity algorithm, the measurement precision of diameter, blood flow, velocity, and wall shear ...

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      Mentions: Ji Yi
    22. OCT‐based angiography of human dermal microvascular reactions to local stimuli: Implications for increasing capillary blood collection volumes

      OCT‐based angiography of human dermal microvascular reactions to local stimuli: Implications for increasing capillary blood collection volumes

      Objectives To measure and compare microvascular responses within the skin of the upper arm to local stimuli, such as heating or rubbing, through the use of optical coherence tomography angiography (OCTA), and to investigate its impact on blood volume collection. Materials and Methods With the use of heat packs or rubbing, local stimulation was applied to the skin of either the left or right upper arm. Data from the stimulated sites were obtained using OCTA comparing pre‐ and post‐stimulation microvascular parameters, such as vessel density, mean vessel diameter, and mean avascular pore size. Additionally, blood was collected using a ...

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    23. Functional optical coherence tomography of neurovascular coupling interactions in the retina

      Functional optical coherence tomography of neurovascular coupling interactions in the retina

      Quantitative evaluation of retinal neurovascular coupling is essential for a better understanding of visual function and early detection of eye diseases. However, there is no established method to monitor coherent interactions between stimulus‐evoked neural activity and hemodynamic responses at high resolution. Here we report a multi‐modal functional optical coherence tomography (OCT) imaging methodology to enable concurrent intrinsic optical signal (IOS) imaging of stimulus‐evoked neural activity and hemodynamic responses at capillary resolution. OCT angiography guided IOS analysis was used to separate neural‐IOS and hemodynamic‐IOS changes in the same retinal image sequence. Frequency flicker stimuli evoked neural ...

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      Mentions: Xincheng Yao
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