1. Articles from Wolfgang Trasischker

    1-8 of 8
    1. Active-passive path-length encoded (APPLE) Doppler OCT

      Active-passive path-length encoded (APPLE) Doppler OCT

      We present a novel active-passive path-length encoded (APPLE) swept source Doppler optical coherence tomography (DOCT) approach, enabling three-dimensional velocity vector reconstruction of moving particles without prior knowledge of the orientation of motion. The developed APPLE DOCT setup allows for non-invasive blood flow measurements in vivo and was primarily designed for quantitative human ocular blood flow investigations. The system’s performance was demonstrated by in vitro flow phantom as well as in vivo retinal vessel bifurcation measurements. Furthermore, total retinal blood flow – a biomarker aiding in diagnosis and monitoring of major ocular diseases such as glaucoma, diabetic retinopathy or central/branch ...

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    2. Depth encoded three-beam swept source Doppler optical coherence tomography

      Depth encoded three-beam swept source Doppler optical coherence tomography

      A novel approach for investigation of human retinal and choroidal blood flow by the means of multi-channel swept source Doppler optical coherence tomography (SS-D-OCT) system is being developed. We present preliminary in vitro measurement results for quantification of the 3D velocity vector of scatterers in a flow phantom. The absolute flow velocity of moving scatterers can be obtained without prior knowledge of flow orientation. In contrast to previous spectral domain (SD-) D-OCT investigations, that already proved the three-channel D-OCT approach to be suitable for in vivo retinal blood flow evaluation, this current work aims for a similar functional approach by ...

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    3. Total retinal blood flow and reproducibility evaluation by three beam optical Doppler tomography

      Total retinal blood flow and reproducibility evaluation by three beam optical Doppler tomography

      We present a three beam optical Doppler tomography (ODT) technique suitable for 3-D velocity and flow measurements to evaluate total retinal blood circulation from and to the optic nerve head (ONH). The system consists of three independent ODT channels. Superluminescent diodes with a central wavelength of 840 nm and a spectral bandwidth of 50 nm were used. The sources are coupled to collimators resting in a specially designed mount to ensure a well-defined beam geometry, necessary for the full reconstruction of the three dimensional velocity vector. The reconstruction works without prior knowledge on the vessel geometry, which is normally required ...

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    4. Total retinal blood flow measurement by three beam Doppler optical coherence tomography

      Total retinal blood flow measurement by three beam Doppler optical coherence tomography

      We present measurements of total retinal blood flow in healthy volunteers using a three beam Doppler optical coherence tomography (D-OCT) technique. This technology has the advantage of a precise determination of the flow vector without the use of any a-priori information on the vessel geometry. Circular D-OCT scans around the optic disc were recorded and venous as well as arterial total blood flow was determined and compared for each subject. The reproducibility of the method was assessed in 6 subjects by repeated measurements. Only small deviations of around 6% between the measurements were found which indicates the high precision of ...

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    5. Single input state polarization sensitive swept source optical coherence tomography based on an all single mode fiber interferometer

      Single input state polarization sensitive swept source optical coherence tomography based on an all single mode fiber interferometer

      We present a newly developed single mode fiber based swept source polarization sensitive optical coherence tomography system using a single input state at 1040 nm. Two non-polarizing fiber based beam splitters are combined to form a Mach-Zehnder interferometer, while two polarizing beam splitters are used to obtain a polarization sensitive detection. Both types of beam splitters solely feature conventional single mode fibers. Polarization control paddles are used to set and maintain the polarization states in the fibers of the interferometer and detection unit. By use of a special paddle alignment scheme we are able to eliminate any bulk optic wave ...

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    6. In vitro and in vivo three-dimensional velocity vector measurement by three-beam spectral-domain Doppler optical coherence tomography

      In vitro and in vivo three-dimensional velocity vector measurement by three-beam spectral-domain Doppler optical coherence tomography

      We developed a three-beam Doppler optical coherence tomography (OCT) system that enables measurement of the velocity vector of moving particles in three-dimensions (3-D). The spatial orientation as well as the magnitude of motion can be determined without prior knowledge of the geometry of motion. The system combines three spectral-domain OCT interferometers whose sample beams are focused at the sample by a common focusing lens at three different angles. This provides three spatially independent velocity components simultaneously from which the velocity vector can be reconstructed. We demonstrate the system in a simple test object (rotating disc), a flow phantom, and for ...

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    7. Retinal polarization-sensitive optical coherence tomography at 1060 nm with 350 kHz A-scan rate using an Fourier domain mode locked laser

      Retinal polarization-sensitive optical coherence tomography at 1060 nm with 350 kHz A-scan rate using an Fourier domain mode locked laser

      We present a novel, high-speed, polarization-sensitive, optical coherence tomography set-up for retinal imaging operating at a central wavelength of 1060 nm which was tested for in vivo imaging in healthy human volunteers. We use the system in combination with a Fourier domain mode locked laser with active spectral shaping which enables the use of forward and backward sweep in order to double the imaging speed without a buffering stage. With this approach and with a custom designed data acquisition system, we show polarization-sensitive imaging with an A-scan rate of 350 kHz. The acquired three-dimensional data sets of healthy human volunteers ...

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    8. Large-field high-speed polarization sensitive spectral domain OCT and its applications in ophthalmology

      Large-field high-speed polarization sensitive spectral domain OCT and its applications in ophthalmology
      We present a novel spectral domain polarization sensitive OCT system (PS-OCT) that operates at an A-scan rate of 70 kHz and supports scan angles of up to 40° × 40°. The high-speed imaging allows the acquisition of up to 1024 × 250 A-scans per 3D scan, which, together with the large field of view, considerably increases the informative value of the images. To demonstrate the excellent performance of the new PS-OCT system, we imaged several healthy volunteers and patients with various diseases such as glaucoma, AMD, Stargardt’s disease, and albinism. The results are compared with clinically established methods such as scanning ...
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    1-8 of 8
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  2. Topics in the News

    1. (8 articles) Medical University of Vienna
    2. (8 articles) Michael Pircher
    3. (8 articles) Christoph K. Hitzenberger
    4. (8 articles) Bernhard Baumann
    5. (4 articles) Teresa Torzicky
    6. (4 articles) Stefan Zotter
    7. (2 articles) Erich Götzinger
    8. (1 articles) Ludwig Maximilian University of Munich
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    11. (1 articles) Boston University
    12. (1 articles) Stanford University
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    14. (1 articles) University Hospital Zurich
    15. (1 articles) University of British Columbia
    16. (1 articles) University of Zurich
    17. (1 articles) Duke University
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    Large-field high-speed polarization sensitive spectral domain OCT and its applications in ophthalmology Retinal polarization-sensitive optical coherence tomography at 1060 nm with 350 kHz A-scan rate using an Fourier domain mode locked laser In vitro and in vivo three-dimensional velocity vector measurement by three-beam spectral-domain Doppler optical coherence tomography Single input state polarization sensitive swept source optical coherence tomography based on an all single mode fiber interferometer Total retinal blood flow measurement by three beam Doppler optical coherence tomography Total retinal blood flow and reproducibility evaluation by three beam optical Doppler tomography Depth encoded three-beam swept source Doppler optical coherence tomography Active-passive path-length encoded (APPLE) Doppler OCT Special Section Guest Editorial: Advances in Retinal Imaging Optical coherence tomography angiography-derived flow density: a review of the influencing factors Changes in retinal and choriocapillaris density in diabetic patients receiving anti-vascular endothelial growth factor treatment using optical coherence tomography angiography Optical coherence tomography of patients with Parkinson’s disease and progressive supranuclear palsy