1. Articles from reginald birngruber

    1-12 of 12
    1. Stromal Nerve Imaging and Tracking Using Micro-Optical Coherence Tomography

      Stromal Nerve Imaging and Tracking Using Micro-Optical Coherence Tomography

      urpose : To image, track and map the nerve fiber distribution in excised rabbit corneas over the entire stromal thickness using micro-optical coherence tomography (µOCT) to develop a screening tool for early peripheral neuropathy. Methods : Excised rabbit corneas were consecutively imaged by a custom-designed µOCT prototype and a commercial laser scanning fluorescence confocal microscope. The µOCT images with a field of view of approximately 1 × 1 mm were recorded with axial and transverse resolutions of approximately 1 µm and approximately 4 µm, respectively. In the volumetric µOCT image data, network maps of hyper-reflective, branched structures traversing different stromal compartments were segmented ...

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    2. Optimization-based vessel segmentation pipeline for robust quantification of capillary networks in skin with optical coherence tomography angiography

      Optimization-based vessel segmentation pipeline for robust quantification of capillary networks in skin with optical coherence tomography angiography

      Optical coherence tomography angiography (OCTA) provides in-vivo images of microvascular perfusion in high resolution. For its application to basic and clinical research, an automatic and robust quantification of the capillary architecture is mandatory. Only this makes it possible to reliably analyze large amounts of image data, to establish biomarkers, and to monitor disease developments. However, due to its optical properties, OCTA images of skin often suffer from a poor signal-to-noise ratio and contain imaging artifacts. Previous work on automatic vessel segmentation in OCTA mostly focuses on retinal and cerebral vasculature. Its applicability to skin and, furthermore, its robustness against imaging ...

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    3. Simple approach for aberration-corrected OCT imaging of the human retina

      Simple approach for aberration-corrected OCT imaging of the human retina

      Aberration-corrected imaging of human photoreceptor cells, whether hardware or software based, presently requires a complex and expensive setup. Here we use a simple and inexpensive off-axis full-field time-domain optical coherence tomography (OCT) approach to acquire volumetric data of an in vivo human retina. Full volumetric data are recorded in 1.3 s. After computationally correcting for aberrations, single photoreceptor cells were visualized. In addition, the numerical correction of ametropia is demonstrated. Our implementation of full-field optical coherence tomography combines a low technical complexity with the possibility for computational image correction.

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    4. In-vivo retinal imaging with off-axis full-field time-domain optical coherence tomography

      In-vivo retinal imaging with off-axis full-field time-domain optical coherence tomography

      With a simple setup, mainly composed of a low coherence light source and a camera, full-field optical coherence tomography (FF-OCT) allows volumetric tissue imaging. However, fringe washout constrains its use in retinal imaging. Here, we present a novel motion-insensitive approach to FF-OCT, which introduces path-length differences between the reference and the sample light in neighboring pixels using an off-axis reference beam. The temporal carrier frequency in scanned time-domain OCT is replaced by a spatial carrier frequency. Volumetric in-vivo FF-OCT measurements of the human retina were acquired in only 1.3 s, comparable to the acquisition times of current clinically used ...

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    5. Device with an OCT system for examining and treating living tissue by means of heating of the tissue by absorbing electromagnetic radiation

      Device with an OCT system for examining and treating living tissue by means of heating of the tissue by absorbing electromagnetic radiation

      A device for examining or treating living tissue by means of local heating of the tissue by absorbing electromagnetic radiation, with at least one radiation source emitting electromagnetic radiation, a control unit for controlling the irradiation parameters of the radiation source, and at least one FD-OCT apparatus with a light source emitting a measurement light for illuminating that tissue region in which the electromagnetic radiation is absorbed by the tissue, characterized by a computational unit for carrying out the following steps: determining the depth-resolved tissue velocity in the radiation direction of the measurement light at a predetermined measurement point of ...

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    6. Validation of two-dimensional and three-dimensional measurements of subpleural alveolar size parameters by optical coherence tomography

      Validation of two-dimensional and three-dimensional measurements of subpleural alveolar size parameters by optical coherence tomography

      Optical coherence tomography (OCT) has been increasingly used for imaging pulmonary alveoli. Only a few studies, however, have quantified individual alveolar areas, and the validity of alveolar volumes represented within OCT images has not been shown. To validate quantitative measurements of alveoli from OCT images, we compared the cross-sectional area, perimeter, volume, and surface area of matched subpleural alveoli from microcomputed tomography (micro-CT) and OCT images of fixed air-filled swine samples. The relative change in size between different alveoli was extremely well correlated ( r > 0.9 , P < 0.0001 ), but OCT images underestimated absolute sizes compared to micro-CT by 27 ...

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    7. Correlation of temperature rise and optical coherence tomography characteristics in patient retinal photocoagulation

      Correlation of temperature rise and optical coherence tomography characteristics in patient retinal photocoagulation

      We conducted a study to correlate the retinal temperature rise during photocoagulation to the afterward detected tissue effect in optical coherence tomography (OCT). 504 photocoagulation lesions were examined in 20 patients. The retinal temperature increase was determined in real-time during treatment based on thermoelastic tissue expansion which was probed by repetitively applied ns laser pulses. The tissue effect was examined on fundus images and OCT images of individualized lesions. We discerned seven characteristic morphological OCT lesion classes. Their validity was confirmed by increasing visibility and diameters. Mean peak temperatures at the end of irradiation ranged from approx. 60 °C to ...

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    8. Imaging thermal expansion and retinal tissue changes during photocoagulation by high speed OCT

      Imaging thermal expansion and retinal tissue changes during photocoagulation by high speed OCT

      Visualizing retinal photocoagulation by real-time OCT measurements may considerably improve the understanding of thermally induced tissue changes and might enable a better reproducibility of the ocular laser treatment. High speed Doppler OCT with 860 frames per second imaged tissue changes in the fundus of enucleated porcine eyes during laser irradiation. Tissue motion, measured by Doppler OCT with nanometer resolution, was correlated with the temperature increase, which was measured non-invasively by optoacoustics. In enucleated eyes, the increase of the OCT signal near the retinal pigment epithelium (RPE) corresponded well to the macroscopically visible whitening of the tissue. At low irradiance, Doppler ...

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    9. Imaging of photothermal tissue expansion via phase sensitive optical coherence tomography

      Imaging of photothermal tissue expansion via phase sensitive optical coherence tomography

      Phase sensitive OCT enables the measurement of thermal expansion in laser irradiated material at high lateral and temporal resolution. In principle, a calculation of the 3D temperature distribution and its temporal evolution should be possible by evaluating the local expansion. This could be utilized for a non-invasive and very fast temperature measurement, e.g. to realize an online dosimetry for photocoagulation. The possibilities of quantitative investigations at high axial and lateral resolution are demonstrated by imaging the reversible thermal expansion in laser irradiated multilayer silicone phantoms.

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    10. Effects on Choroidal Neovascularization after Anti-VEGF Upload Using Intravitreal Ranibizumab, as Determined by Spectral Domain-Optical Coherence Tomography

      Purpose. It is unclear whether anti-VEGF monotherapy in age-related macular degeneration (AMD) achieves morphologic CNV regression or only stops further CNV growth. In this study, spectral domain-optical coherence tomography (SD-OCT) was used to image CNV structure before and after anti-VEGF treatment. Methods. Out of 107 consecutive patients, a prospective CNV evaluation was possible in 78 of them. Newly diagnosed CNV (classic CNV: n = 16; occult CNV: n = 54; minimal classic CNV: n = 8) due to AMD was imaged before and 4 weeks after anti-VEGF upload in three intravitreal injections of ranibizumab. Qualitative (structural changes) and quantitative measurements (diameter and thickness ...
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    11. Effects on Choroidal Neovascularizations after Anti-VEGF Upload Using Intravitreal Ranibizumab as Determined by Spectral Domain Optical Coherence Tomography

      Purpose: To image CNV structure before and after anti-VEGF treatment using spectral domain optical coherence tomography (SD-OCT). Material and methods: In 78 patients newly diagnosed CNVs (classic CNV: n=16; occult CNV: n=54; minimal classic CNV: n=8) due to AMD were imaged before and 4 weeks after anti-VEGF upload with 3 intravitreal injections of Ranibizumab. Qualitative (structural changes) and quantitative measurements (diameter and thickness) of the CNVs were obtained from the OCT images using the Heidelberg Eye Explorer software. Results: Classic CNV components were observed above the RPE/photoreceptor complex, whereas occult CNVs stayed below. Qualitatively, overall CNV ...
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    12. Process and arrangement for examining a section of the eye

      Systems, methods, and apparatus are provided for deriving the relative position of an eye by tracking a boundary of the eye such as the limbus (i.e., the interface between the white sclera and the colored iris). A technique for tracking the position of the eye of patient comprises directing light to an annular region of the eye between the sclera and the iris and receiving reflected light from that region. The intensity of the reflected light is then measured to determine a relative position of the eye. In some embodiments, the measured region is scanned around the boundary. In ...
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    1-12 of 12
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  2. Topics in the News

    1. (12 articles) Reginald Birngruber
    2. (10 articles) University of Lübeck
    3. (6 articles) Gereon Hüttmann
    4. (3 articles) Massachusetts General Hospital
    5. (3 articles) Harvard University
    6. (2 articles) Guillermo J. Tearney
    7. (2 articles) Carsten Framme
    8. (1 articles) Brett E. Bouma
    9. (1 articles) Eman Namati
    10. (1 articles) Thorlabs
    11. (1 articles) Johns Hopkins University
    12. (1 articles) Dalhousie University
    13. (1 articles) Technical University of Munich
    14. (1 articles) University of Toronto
    15. (1 articles) Baylor College of Medicine
    16. (1 articles) Gadi Wollstein
    17. (1 articles) Joel S. Schuman
    18. (1 articles) Hiroshi Ishikawa
    19. (1 articles) Irina V. Larina
    20. (1 articles) Carl Zeiss Meditec
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    Imaging of photothermal tissue expansion via phase sensitive optical coherence tomography Imaging thermal expansion and retinal tissue changes during photocoagulation by high speed OCT Correlation of temperature rise and optical coherence tomography characteristics in patient retinal photocoagulation Validation of two-dimensional and three-dimensional measurements of subpleural alveolar size parameters by optical coherence tomography Device with an OCT system for examining and treating living tissue by means of heating of the tissue by absorbing electromagnetic radiation In-vivo retinal imaging with off-axis full-field time-domain optical coherence tomography Optimization-based vessel segmentation pipeline for robust quantification of capillary networks in skin with optical coherence tomography angiography Cooperative low-rank models for removing stripe noise from OCTA images MS-CAM: Multi-Scale Class Activation Maps for Weakly-supervised Segmentation of Geographic Atrophy Lesions in SD-OCT Images Attention-guided 3D-CNN Framework for Glaucoma Detection and Structural-Functional Association using Volumetric Images Machine Learning Techniques for Ophthalmic Data Processing: A Review Dynamic Imaging of Mouse Embryos and Cardiac Development in Static Culture