1. Articles from Rainer A. Leitgeb

    1-24 of 76 1 2 3 4 »
    1. Synthetic subaperture-based angle-independent Doppler flow measurements using single-beam line field optical coherence tomography in vivo

      Synthetic subaperture-based angle-independent Doppler flow measurements using single-beam line field optical coherence tomography in vivo

      We demonstrate a synthetic subaperture-based angle-independent Doppler flow calculation, using a line field spectral domain optical coherence tomography system. The high speed of the system features a high phase stability over the volume, which is necessary to apply synthetic subapertures in the aperture plane. Thus, the flow component for each subaperture can be reconstructed in postprocessing. Capillary phantom and in vivo retinal imaging experiments were performed to validate and demonstrate angle-independent Doppler flow calculation

      Read Full Article
    2. Numerically focused full-field swept-source optical coherence microscopy with structured illumination

      Numerically focused full-field swept-source optical coherence microscopy with structured illumination

      This paper presents an experimental investigation of the possibility of transverse resolution improvement combined with effective numerically focused 3D imaging in full-field swept-source optical coherence microscopy (OCM) by using structured illumination and specific numerical post-processing. The possibility of transverse resolution improvement of the OCM coherence signal combined with the possibility of numerical focusing is demonstrated by imaging a resolution test target in the optical focus and defocus regions. The possibility of numerically focused 3D imaging with high transverse resolution is further demonstrated by imaging a 3D phantom and a biological sample. The results obtained demonstrate the feasibility and prospects of ...

      Read Full Article
    3. Multimodal Optical Medical Imaging Concepts based on Optical Coherence Tomography

      Multimodal Optical Medical Imaging Concepts based on Optical Coherence Tomography

      Optical medical imaging techniques in general exhibit outstanding resolution and molecule-specific contrast. They come however with a limited penetration in depth and small field of view. Multimodal concepts help to combine complementary strengths of different imaging technologies. The present article reviews the advantages of optical multimodal imaging concepts using optical coherence tomography (OCT) as core technology. In particular we first discuss polarization sensitive OCT, Doppler OCT and OCT angiography, OCT elastography and spectroscopic OCT as intramodal concepts. To highlight intermodal imaging concepts, we then chose the combination of OCT with photoacoustics, and with non-linear optical microscopy. The selected multimodal concepts ...

      Read Full Article
    4. Feature Of The Week 07/01/2018: Endoscopic Optical Coherence Tomography with a Flexible Fiber Bundle

      Feature Of The Week 07/01/2018: Endoscopic Optical Coherence Tomography with a Flexible Fiber Bundle

      We demonstrate in vivo endoscopic optical coherence tomography (OCT) imaging in the forward direction using a flexible fiber bundle (FB). In comparison to current conventional forward-looking probe schemes, our approach simplifies the endoscope design by avoiding the integration of any beam steering components in the distal probe end due to two-dimensional scanning of a focused light beam over the proximal FB surface. We describe the challenges that arise when OCT imaging with an FB is performed, such as multimoding or cross coupling. The performance of different FBs varying in parameters, such as numerical aperture, core size, core structure, and flexibility ...

      Read Full Article
    5. Endoscopic optical coherence tomography with a flexible fiber bundle

      Endoscopic optical coherence tomography with a flexible fiber bundle

      We demonstrate in vivo endoscopic optical coherence tomography (OCT) imaging in the forward direction using a flexible fiber bundle (FB). In comparison to current conventional forward-looking probe schemes, our approach simplifies the endoscope design by avoiding the integration of any beam steering components in the distal probe end due to two-dimensional scanning of a focused light beam over the proximal FB surface. We describe the challenges that arise when OCT imaging with an FB is performed, such as multimoding or cross coupling. The performance of different FBs varying in parameters, such as numerical aperture, core size, core structure, and flexibility ...

      Read Full Article
    6. Compact akinetic swept source optical coherence tomography angiography at 1060 nm supporting a wide field of view and adaptive optics imaging modes of the posterior eye

      Compact akinetic swept source optical coherence tomography angiography at 1060 nm supporting a wide field of view and adaptive optics imaging modes of the posterior eye

      Imaging of the human retina with high resolution is an essential step towards improved diagnosis and treatment control. In this paper, we introduce a compact, clinically user-friendly instrument based on swept source optical coherence tomography (SS-OCT). A key feature of the system is the realization of two different operation modes. The first operation mode is similar to conventional OCT imaging and provides large field of view (FoV) images (up to 45° × 30°) of the human retina and choroid with standard resolution. The second operation mode enables it to optically zoom into regions of interest with high transverse resolution using adaptive ...

      Read Full Article
    7. Endoscopic optical coherence tomography with a flexible fiber bundle

      Endoscopic optical coherence tomography with a flexible fiber bundle

      We demonstrate in vivo endoscopic optical coherence tomography (OCT) imaging in the forward direction using a flexible fiber bundle. In comparison to current conventional forward looking probe schemes, our approach simplifies the endoscope design by avoiding the integration of any beam steering components in the distal probe end due to 2D scanning of a focused light beam over the proximal fiber bundle surface. We describe the challenges that arise when OCT imaging with a fiber bundle is performed, such as multimoding or cross-coupling. The performance of different fiber bundles with varying parameters such as numerical aperture, core size and core ...

      Read Full Article
    8. Holographic line field en-face OCT with digital adaptive optics in the retina in vivo

      Holographic line field en-face OCT with digital adaptive optics in the retina in vivo

      We demonstrate a high-resolution line field en-face time domain optical coherence tomography (OCT) system using an off-axis holography configuration. Line field en-face OCT produces high speed en-face images at rates of up to 100 Hz. The high frame rate favors good phase stability across the lateral field-of-view which is indispensable for digital adaptive optics (DAO). Human retinal structures are acquired in-vivo with a broadband light source at 840 nm, and line rates of 10 kHz to 100 kHz. Structures of different retinal layers, such as photoreceptors, capillaries, and nerve fibers are visualized with high resolution of 2.8 µm and ...

      Read Full Article
    9. Non-invasive multimodal optical coherence and photoacoustic tomography for human skin imaging

      Non-invasive multimodal optical coherence and photoacoustic tomography for human skin imaging

      The cutaneous vasculature is involved in many diseases. Current clinical examination techniques, however, cannot resolve the human vasculature with all plexus in a non-invasive manner. By combining an optical coherence tomography system with angiography extension and an all optical photoacoustic tomography system, we can resolve in 3D the blood vessels in human skin for all plexus non-invasively. With a customized imaging unit that permits access to various parts of patients’ bodies, we applied our multimodality imaging system to investigate several different types of skin conditions. Quantitative vascular analysis is given for each of the dermatological conditions to show the potential ...

      Read Full Article
    10. Noniterative digital aberration correction for cellular resolution retinal optical coherence tomography in vivo

      Noniterative digital aberration correction for cellular resolution retinal optical coherence tomography in vivo

      High-resolution imaging of the human retina has always been a challenge due to imperfect optical properties of the human cornea and lens, which limit the achievable resolution. We present a noniterative digital aberration correction (DAC) to achieve aberration-free cellular-level resolution in optical coherence tomography (OCT) images of the human retina in vivo . The system used is a line-field spectral-domain OCT system with a high tomogram rate, reaching 2.5 kHz. Such a high speed enables us to successfully apply digital aberration correction for not only imaging of human cone photoreceptors but also to obtain an aberration- and defocus-corrected 3D volume ...

      Read Full Article
    11. Combined multi-modal photoacoustic tomography, optical coherence tomography (OCT) and OCT angiography system with an articulated probe for in vivo human skin structure and vasculature imaging

      Combined multi-modal photoacoustic tomography, optical coherence tomography (OCT) and OCT angiography system with an articulated probe for in vivo human skin structure and vasculature imaging

      Cutaneous blood flow accounts for approximately 5% of cardiac output in human and plays a key role in a number of a physiological and pathological processes. We show for the first time a multi-modal photoacoustic tomography (PAT), optical coherence tomography (OCT) and OCT angiography system with an articulated probe to extract human cutaneous vasculature in vivo in various skin regions. OCT angiography supplements the microvasculature which PAT alone is unable to provide. Co-registered volumes for vessel network is further embedded in the morphologic image provided by OCT. This multi-modal system is therefore demonstrated as a valuable tool for comprehensive non-invasive ...

      Read Full Article
    12. Post Doc Position for in-vivo Biomicroscopy at the Medical University of Vienna

      Post Doc Position for in-vivo Biomicroscopy at the Medical University of Vienna

      An academic PostDoc position is available from September 1, 2016 at the Christian Doppler Laboratory for Innovative Optical Imaging and Its Translation to Medicine, Center for Medical Physics and Biomedical Engineering. We offer a research position in the field of biomedical imaging with strong interdisciplinary (door to door) collaboration with clinicians as well as biologists. Our research group is developing novel coherent biomedical imaging methods to overcome the conventional resolution limits and to pave the way from pure structural to functional tissue and cell metabolic imaging. This involves profound knowledge of theoretical and experimental optics, system engineering, data and image ...

      Read Full Article
    13. Key Developments for Partial Coherence Biometry and Optical Coherence Tomography in the Human Eye Made in Vienna

      Key Developments for Partial Coherence Biometry and Optical Coherence Tomography in the Human Eye Made in Vienna

      Purpose : To describe key developments of optical biometry and optical coherence tomography (OCT) for ophthalmic applications made by one of the pioneering research groups. Methods : Partial coherence interferometry (PCI) as the basic ranging technology for modern optical biometry and for OCT was introduced for biomedical applications in the 1980s. Later, Fourier domain (FD) OCT was introduced and demonstrated to provide superior sensitivity as compared to time domain OCT. Further developments comprised ultrahigh-resolution OCT and deep-penetration OCT at wavelengths of approximately 1050 nm. Important functional extensions comprise Doppler OCT/OCT angiography, polarization-sensitive OCT, and adaptive optics OCT. Results : High-precision PCI biometry ...

      Read Full Article
    14. Line-field parallel swept source interferometric imaging at up to 1  MHz

      Line-field parallel swept source interferometric imaging at up to 1  MHz

      We present a novel medical imaging modality based on optical coherence tomography (OCT) that enables in vivo 3D tomography at acquisition rates up to 1 MHz. Line field parallel swept source interferometric imaging (LPSI) combines line-field swept source OCT with modulation of the interferometric signal in spatial direction for full range imaging. This method enables high speed imaging with cost-effective and commercially available technology. We explain the realization of the LPSI setup, acquisition, and postprocessing and finally demonstrate 3D in vivo imaging of human nail fold. To the best of our knowledge, sensitivity and depth penetration are competitive with respective ...

      Read Full Article
    15. Systems and methods for bidirectional functional optical coherence tomography

      Systems and methods for bidirectional functional optical coherence tomography

      Methods for determining improving quantitative and qualitative motion contrast information collected with optical coherence tomography (OCT) data are presented. In one embodiment, flow within a cross-sectional area of a sample is calculated independent of the Doppler and en face angles using a bidirectional OCT system. In another embodiment, motion contrast images are improved by averaging motion contrast information collected from a bidirectional OCT system.

      Read Full Article
    16. Intra- and Inter-Frame Differential Doppler Optical Coherence Tomography

      Intra- and Inter-Frame Differential Doppler Optical Coherence Tomography

      Spectrometer based optical coherence tomography suffers from fringe washout for fast flow, a drawback for flow visualization, which is of interest for both lable-free optical angiography and flow quantification. We presented a method, which can be used to contrast very fast flows, while maintaining relatively low A-scan rates. It is based on introducing a phase shift of during acquisition such that the interference fringes associated to moving sample structures are recovered depending on the axial velocity. This enables the use of slower line scan cameras for measuring the fast blood flows within the large vessels in the region of the ...

      Read Full Article
    17. Blood flow velocity vector field reconstruction from dual-beam bidirectional Doppler OCT measurements in retinal veins

      Blood flow velocity vector field reconstruction from dual-beam bidirectional Doppler OCT measurements in retinal veins

      In this paper, we demonstrate the possibility to reconstruct the actual blood flow velocity vector field in retinal microvessels from dual-beam bidirectional Doppler optical coherence tomography measurements. First, for a better understanding of measured phase patterns, several flow situations were simulated on the basis of the known dual beam measurement geometry. We were able to extract the vector field parameters that determine the measured phase pattern, allowing for the development of an algorithm to reconstruct the velocity vector field from measured phase data. In a next step, measurements were performed at a straight vessel section and at a venous convergence ...

      Read Full Article
    18. Anisotropic aberration correction using region of interest based digital adaptive optics in Fourier domain OCT

      Anisotropic aberration correction using region of interest based digital adaptive optics in Fourier domain OCT

      In this paper a numerical technique is presented to compensate for anisotropic optical aberrations, which are usually present across the lateral field of view in the out of focus regions, in high resolution optical coherence tomography and microscopy (OCT/OCM) setups. The recorded enface image field at different depths in the tomogram is digitally divided into smaller sub-regions or the regions of interest (ROIs), processed individually using subaperture based digital adaptive optics (DAO), and finally stitched together to yield a final image with a uniform diffraction limited resolution across the entire field of view (FOV). Using this method, a sub-micron ...

      Read Full Article
    19. Line-field parallel swept source MHz OCT for structural and functional retinal imaging

      Line-field parallel swept source MHz OCT for structural and functional retinal imaging

      We demonstrate three-dimensional structural and functional retinal imaging with line-field parallel swept source imaging (LPSI) at acquisition speeds of up to 1 MHz equivalent A-scan rate with sensitivity better than 93.5 dB at a central wavelength of 840 nm. The results demonstrate competitive sensitivity, speed, image contrast and penetration depth when compared to conventional point scanning OCT. LPSI allows high-speed retinal imaging of function and morphology with commercially available components. We further demonstrate a method that mitigates the effect of the lateral Gaussian intensity distribution across the line focus and demonstrate and discuss the feasibility of high-speed optical angiography ...

      Read Full Article
    20. 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 ...

      Read Full Article
    21. Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging

      Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging

      A wide variety of ocular diseases are associated with abnormalities in ocular circulation. As such, there is considerable interest in techniques for quantifying retinal blood flow, among which Doppler optical coherence tomography (OCT) may be the most promising. We present an approach to measure retinal blood flow in the rat using a new optical system that combines the measurement of blood flow velocities via Doppler Fourier-domain optical coherence tomography and the measurement of vessel diameters using a fundus camera-based technique. Relying on fundus images for extraction of retinal vessel diameters instead of OCT images improves the reliability of the technique ...

      Read Full Article
    22. Academic Post Doc Position in Biomedical Optics at the Medical University Vienna

      Academic Post Doc Position in Biomedical Optics at the Medical University Vienna

      An academic PostDoc position is available from December 1, 2014 in the Biomedical Optics Division, Center for Medical Physics and Biomedical Engineering. Depending on the candidates’ research record the position may be continued as tenure track after the first two to three years. We offer an academic position at an international highly recognized research institute in the field of biomedical imaging with strong interdisciplinary (door to door) collaboration with clinicians as well as biologists. Our research group is developing novel coherent biomedical imaging methods to pave the way from pure structural to functional tissue and cell metabolic imaging. This involves ...

      Read Full Article
    23. Line-field parallel swept source interferometric imaging at up to 1MHz

      Line-field parallel swept source interferometric imaging at up to 1MHz

      We present a novel medical imaging modality based on optical coherence tomography (OCT) that enables in vivo 3D tomography at acquisition rates up to 1 MHz. Line field parallel swept source interferometric imaging (LPSI) combines line-field swept source OCT with modulation of the interferometric signal in spatial direction for full range imaging. This method enables high speed imaging with cost-effective and commercially available technology. We explain the realization of the LPSI setup, acquisition, and postprocessing and finally demonstrate 3D in vivo imaging of human nail fold. To the best of our knowledge, sensitivity and depth penetration are competitive with respective ...

      Read Full Article
    24. Optical coherence tomography today: speed, contrast, and multimodality

      Optical coherence tomography today: speed, contrast, and multimodality

      In the last 25 years, optical coherence tomography (OCT) has advanced to be one of the most innovative and most successful translational optical imaging techniques, achieving substantial economic impact as well as clinical acceptance. This is largely owing to the resolution improvements by a factor of 10 to the submicron regime and to the imaging speed increase by more than half a million times to more than 5 million A-scans per second, with the latter one accomplished by the state-of-the-art swept source laser technologies that are reviewed in this article. In addition, parallelization of OCT detection, such as line-field and ...

      Read Full Article
    1-24 of 76 1 2 3 4 »
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (75 articles) Rainer A. Leitgeb
    2. (70 articles) Medical University of Vienna
    3. (29 articles) Tilman Schmoll
    4. (16 articles) Cedric Blatter
    5. (14 articles) Wolfgang Drexler
    6. (14 articles) Branislav Grajciar
    7. (11 articles) Christoph K. Hitzenberger
    8. (10 articles) Michael Pircher
    9. (10 articles) Abhishek Kumar
    10. (9 articles) Erich Götzinger
  3. Popular Articles

  4. Picture Gallery

    Single-camera polarization-sensitive spectral-domain OCT by spatial frequency encoding In vivo functional retinal optical coherence tomography Stable absolute flow estimation with Doppler OCT based on virtual circumpapillary scans High-speed functional OCT with self-reconstructive Bessel illumination at 1300nm Extended focus high-speed swept source OCT with self-reconstructive illumination Speckle noise reduction in high speed polarization sensitive spectral domain optical coherence tomography Current Technologies for High-Speed and Functional Imaging with Optical Coherence Tomography (Book Chapter) Post Doc Position for in-vivo Biomicroscopy at the Medical University of Vienna Image contrast correction method in full-field optical coherence tomography Evaluation of posterior vitreous detachment using ultrasonography and optical coherence tomography Optical coherence tomography angiography characteristics of acute retinal arterial occlusion Computed Tomography–Mediated Registration of Trapeziometacarpal Articular Cartilage Using Intraarticular Optical Coherence Tomography and Cryomicrotome Imaging: A Cadaver Study