1. Articles from harald sattmann

    1-16 of 16
    1. Comprehensive vascular imaging using optical coherence tomography-based angiography and photoacoustic tomography

      Comprehensive vascular imaging using optical coherence tomography-based angiography and photoacoustic tomography

      Studies have proven the relationship between cutaneous vasculature abnormalities and dermatological disorders, but to image vasculature noninvasively in vivo , advanced optical imaging techniques are required. In this study, we imaged a palm of a healthy volunteer and three subjects with cutaneous abnormalities with photoacoustic tomography (PAT) and optical coherence tomography with angiography extension (OCTA). Capillaries in the papillary dermis that are too small to be discerned with PAT are visualized with OCTA. From our results, we speculate that the PA signal from the palm is mostly from hemoglobin in capillaries rather than melanin, knowing that melanin concentration in volar skin ...

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    2. High-speed polarization sensitive optical coherence tomography scan engine based on Fourier domain mode locked laser

      High-speed polarization sensitive optical coherence tomography scan engine based on Fourier domain mode locked laser

      We report on a new swept source polarization sensitive optical coherence tomography scan engine that is based on polarization maintaining (PM) fiber technology. The light source is a Fourier domain mode locked laser with a PM cavity that operates in the 1300 nm wavelength regime. It is equipped with a PM buffer stage that doubles the fundamental sweep frequency of 54.5 kHz. The fiberization allows coupling of the scan engine to different delivery probes. In a first demonstration, we use the system for imaging human skin at an A-scan rate of 109 kHz. The system illuminates the sample with ...

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    3. Polarization sensitive optical coherence tomography of melanin provides intrinsic contrast based on depolarization

      Polarization sensitive optical coherence tomography of melanin provides intrinsic contrast based on depolarization

      Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of OCT. In addition to imaging based on tissue reflectivity, PS-OCT also enables depth-resolved mapping of sample polarization properties such as phase-retardation, birefringent axis orientation, Stokes vectors, and degree of polarization uniformity (DOPU). In this study, PS-OCT was used to investigate the polarization properties of melanin. In-vitro measurements in samples with varying melanin concentrations revealed polarization scrambling, i.e. depolarization of backscattered light. Polarization scrambling in the PS-OCT images was more pronounced for higher melanin concentrations and correlated with the concentration of the melanin granules in the phantoms. Moreover, in-vivo ...

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    4. Speckle noise reduction in high speed polarization sensitive spectral domain optical coherence tomography

      Speckle noise reduction in high speed polarization sensitive spectral domain optical coherence tomography
      We present a high speed polarization sensitive spectral domain optical coherence tomography system based on polarization maintaining fibers and two high speed CMOS line scan cameras capable of retinal imaging with up to 128 k A-lines/s. This high imaging speed strongly reduces motion artifacts and therefore averaging of several B-scans is possible, which strongly reduces speckle noise and improves image quality. We present several methods for averaging retardation and optic axis orientation, the best one providing a 5 fold noise reduction. Furthermore, a novel scheme of calculating images of degree of polarization uniformity is presented. We quantitatively compare the ...
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    5. Speckle noise reduction by averaging in polarization sensitive spectral domain optical coherence tomography

      Speckle noise reduction by averaging in polarization sensitive spectral domain optical coherence tomography
      We demonstrate an ultra high speed fiber based polarization sensitive spectral domain optical coherence tomography system, using two ultra high speed CMOS line scan cameras. With this system an A-scan rate of up to 128 kHz was achieved. The system is based on polarization maintaining fibers and retrieves the backscattered intensity, retardation and optic axis orientation with only one A-scan per measurement location. This high speed data acquisition enables averaging of several acquired B-scans of intensity, retardation, optic axis orientation, and Stokes vectors, which strongly reduces speckle noise. We discuss different averaging techniques and compare the results in healthy human ...
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    6. In vivo observation of human retinal-cone outer-segment renewal

      In vivo observation of human retinal-cone outer-segment renewal
      Cone-disk shedding and generation can be observed using transverse-scanning optical coherence tomography and scanning-laser ophthalmoscopy. Vision is one of the most complex human senses. The eye projects images from our environment onto the retina, which consists of a variety of different cells. The retina preprocesses this information before sending it to the brain as electrical signals. Many different retinal diseases—such as age-related macular degeneration—distort the fragile retinal structure, leading to (for example) reduced visual perception and eventual blindness. Maintenance of a healthy retina requires interactions between its photosensitive cells and the retinal-pigment epithelium (RPE). There are two different ...
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    7. Segmentation and quantification of retinal lesions in age-related macular degeneration using polarization-sensitive optical coherence tomography

      Segmentation and quantification of retinal lesions in age-related macular degeneration using polarization-sensitive optical coherence tomography
      We present polarization-sensitive optical coherence tomography (PS-OCT) for quantitative assessment of retinal pathologies in age-related macular degeneration (AMD). On the basis of the polarization scrambling characteristics of the retinal pigment epithelium, novel segmentation algorithms were developed that allow one to segment pathologic features such as drusen and atrophic zones in dry AMD as well as to determine their dimensions. Results from measurements in the eyes of AMD patients prove the ability of PS-OCT for quantitative imaging based on the retinal features polarizing properties. Repeatability measurements were performed in retinas diagnosed with drusen and geographic atrophy in order to evaluate the ...
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    8. In vivo investigation of human cone photoreceptors with SLO/OCT in combination with 3D motion correction on a cellular level

      In vivo investigation of human cone photoreceptors with SLO/OCT in combination with 3D motion correction on a cellular level
      We present a further improvement of our SLO/OCT imaging system which enables to practically eliminate all eye motion artifacts with a correction accuracy approaching sub-cellular dimensions. Axial eye tracking is achieved by using a hardware based, high speed tracking system that consists of a rapid scanning optical delay line in the reference arm of the interferometer. A software based algorithm is employed to correct for transverse eye motion in a post-processing step. The instrument operates at a frame rate of 40 en-face fps with a field of view of ~1°x1°. Dynamic focusing enables the recording of 3D volumes ...
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    9. Quantification of retinal lesions by polarization sensitive optical coherence tomography

      Quantification of retinal lesions by polarization sensitive optical coherence tomography
      Segmentation of retinal structures is an important step for quantitative diagnostic applications of optical coherence tomography (OCT) in ophthalmology. Contrary to previous segmentation algorithms that are based on intensity images, we use the tissue specific contrast provided by polarization sensitive (PS) OCT for segmentation of retinal layers and lesions. Our algorithms exploit the polarization scrambling property of the retinal pigment epithelium (RPE) in a first step to segment the RPE. The RPE is then used as a "backbone" to identify further structures like the normal RPE position (indicating Bruch's membrane) or the posterior tips of the photoreceptors. In a ...
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    10. Phase contrast coherence microscopy based on transverse scanning

      Phase contrast coherence microscopy based on transverse scanning
      We present what we believe to be a novel approach to measuring optical path length differences with a precision of a few nanometers. The instrument is based on transverse scanning or en-face optical coherence tomography. Owing to the fast motion of the scanning beam over the sample, excellent phase stability in the transverse direction is achieved. Hence, phase changes caused by the varying optical path lengths within the sample arm occur with high frequency in the fast scanning direction. These changes are well separated from the rather slow phase changes introduced by jitter within the interferometer and can therefore be ...
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    11. Imaging the human retina in vivo with combined spectral-domain polarization-sensitive optical coherence tomography and scanning laser ophthalmoscopy

      Polarization-sensitive (PS) optical coherence tomography (OCT) allows for depth-resolved measurement of light polarizing properties of different layers in the human retina. Since their inherent polarizing properties are different, the retinal structures can be identified using PS-OCT. We present an ... [Proc. SPIE 7163, 71630N (2009)] published Wed Feb 18, 2009.
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    12. Ultrahigh resolution optical coherence tomography and pancorrection for cellular imaging of the living human retina

      Cellular in vivo visualization of the three dimensional architecture of individual human foveal cone photoreceptors is demonstrated by combining ultrahigh resolution optical coherence tomography and a novel adaptive optics modality. Isotropic resolution in the order of 2-3µm, estimated from ... [Opt. Express 16, 11083-11094 (2008)]

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    13. Simultaneous SLO/OCT imaging of the human retina with axial eye motion correction

      It has been shown that transversal scanning (or en-face) optical coherence tomography (TS-OCT) represents an imaging modality capable to record high isotropic resolution images of the human retina in vivo. However, axial eye motion still remains a challenging problem of this technique. In this paper we introduce a novel method to compensate for this eye motion. An auxiliary spectral domain partial coherence interferometer (SD-PCI) was integrated into an existing TS-OCT system and used to measure accurately the position of the cornea. A light source emitting at 1310nm was used in the additional interferometer which enabled a nearly loss free coupling ...

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    14. Serial Endoscopy in Azoxymethane Treated Mice Using Ultra-High Resolution Optical Coherence Tomography

      Serial Endoscopy in Azoxymethane Treated Mice Using Ultra-High Resolution Optical Coherence Tomography

      Purpose: Optical coherence tomography (OCT) is a minimally invasive, depth-resolved imaging tool that can be implemented in a small diameter endoscope for imaging mouse models of colorectal cancer (CRC). In this study, we utilized ultrahigh resolution (UHR) OCT to serially image the lower colon of azoxymethane (AOM) treated A/J mouse models of CRC in order to monitor the progression of neoplastic transformations and determine if OCT is capable of identifying early disease. Experimental Design: Thirteen AOM treated A/J and two control A/J mice were surveyed at four timepoints (8, 14, 22, and 26 weeks post AOM treatment ...

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    15. Optical coherence tomography with dynamic coherent focus

      In coherence tomography, an interferometric measurement light beam scans the measurement object and is focused for improving the transverse resolution. In order to achieve a high transverse resolution over the entire object depth, the focal displacement and the change in path length in the measurement light beam for maintaining the coherence of the focus is achieved by one and the same moving optical element in the measurement light beam. The present invention achieves this by a particularly simple and easily adjustable arrangement which is characterized by especially low light loss in the measurement beam path.
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    1-16 of 16
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  2. Topics in the News

    1. (16 articles) Harald Sattmann
    2. (15 articles) Medical University of Vienna
    3. (12 articles) Michael Pircher
    4. (12 articles) Erich Götzinger
    5. (11 articles) Christoph K. Hitzenberger
    6. (10 articles) Bernhard Baumann
    7. (5 articles) Ursula Schmidt-Erfurth
    8. (5 articles) Christopher Schütze
    9. (4 articles) Christian Ahlers
    10. (4 articles) Rainer A. Leitgeb
    11. (2 articles) Columbia University
    12. (2 articles) Christine P. Hendon
    13. (2 articles) Canon Medical Systems
    14. (1 articles) University of Houston
    15. (1 articles) Kyoto University Graduate School of Medicine
    16. (1 articles) Dmitry A. Terpelov
    17. (1 articles) David D. Sampson
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    Serial Endoscopy in Azoxymethane Treated Mice Using Ultra-High Resolution Optical Coherence Tomography Quantitative assessment of retinal disorders using polarization-sensitive optical coherence tomography Quantification of retinal lesions by polarization sensitive optical coherence tomography In vivo investigation of human cone photoreceptors with SLO/OCT in combination with 3D motion correction on a cellular level Segmentation and quantification of retinal lesions in age-related macular degeneration using polarization-sensitive optical coherence tomography Speckle noise reduction by averaging in polarization sensitive spectral domain optical coherence tomography Speckle noise reduction in high speed polarization sensitive spectral domain optical coherence tomography Miniaturizing medical imaging, sensing technology On-chip tunable photonic delay line Canon Xephilio OCT-A1 Optical Coherence Tomography Device Receives FDA 510(k) Clearance Subintimal Versus Intraplaque Recanalization of Coronary Chronic Total Occlusions: Mid-Term Angiographic and OCT Findings From the ISAR-OCT-CTO Registry Review of methods and applications of attenuation coefficient measurements with optical coherence tomography