1. Bernhard Baumann

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    1. Mentioned In 106 Articles

    2. Ex-vivo Alzheimer’s disease brain tissue investigation: a multiscale approach using 1060-nm swept source optical coherence tomography for a direct correlation to histology

      Ex-vivo Alzheimer’s disease brain tissue investigation: a multiscale approach using 1060-nm swept source optical coherence tomography for a direct correlation to histology
      Significance: Amyloid-beta (A-) plaques are pathological protein deposits formed in the brain of Alzheimers disease (AD) patients upon disease progression. Further research is needed to elucidate the complex underlying mechanisms involved in their formation using label-free, tissue preserving, and volumetric techniques. Aim: The aim is to achieve a one-to-one correlation of optical coherence tomography (OCT) data to histological micrographs of brain tissue using 1060-nm swept source OCT. Approach: A- plaques ...
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    3. Attenuation coefficient as a quantitative parameter for analyzing cataracts with optical coherence tomography

      Attenuation coefficient as a quantitative parameter for analyzing cataracts with optical coherence tomography
      Crystalline lenses of mice were imaged in vivo with a custom-made swept-source optical coherence tomography system. The use of the attenuation coefficient as a quantitative parameter for investigating the lens opacities magnitude is proposed, demonstrating a significant difference between the values retrieved from cataractous and normal mouse lenses.
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    4. Improved Diagnostic Imaging of Brain Tumors by Multimodal Microscopy and Deep Learning

      Improved Diagnostic Imaging of Brain Tumors by Multimodal Microscopy and Deep Learning
      Fluorescence-guided surgery is a state-of-the-art approach for intraoperative imaging during neurosurgical removal of tumor tissue. While the visualization of high-grade gliomas is reliable, lower grade glioma often lack visible fluorescence signals. Here, we present a hybrid prototype combining visible light optical coherence microscopy (OCM) and high-resolution fluorescence imaging for assessment of brain tumor samples acquired by 5-aminolevulinic acid (5-ALA) fluorescence-guided surgery. OCM provides high-resolution information of the inherent tissue scattering ...
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    5. Indocyanine green provides absorption and spectral contrast for optical coherence tomography at 840  nm in vivo

      Indocyanine green provides absorption and spectral contrast for optical coherence tomography at 840  nm in vivo
      In recent years, there has been growing interest in the application of exogenous contrast agents to supplement the traditional strengths of optical coherence tomography (OCT) and provide additional biological information. In this Letter, we present how indocyanine green, a common fluorescent contrast agent approved by the United States Food and Drug Administration, can provide absorption and spectral contrast for OCT imaging in the mouse eye in vivo . We further demonstrate ...
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    6. Three-dimensional visualization of opacifications in the murine crystalline lens by in vivo optical coherence tomography

      Three-dimensional visualization of opacifications in the murine crystalline lens by in vivo optical coherence tomography
      Diagnostic classification techniques used to diagnose cataracts, the worlds leading cause of blindness, are currently based on subjective methods. Here, we present optical coherence tomography as a noninvasive tool for volumetric visualization of lesions formed in the crystalline lens. A custom-made swept-source optical coherence tomography (SS-OCT) system was utilized to investigate the murine crystalline lens. In addition to imaging cataractous lesions in aged wildtype mice, we studied the structure and ...
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    7. Optical Coherence Tomography Findings in the Retinas of SOD1 Knockout Mice

      Optical Coherence Tomography Findings in the Retinas of SOD1 Knockout Mice
      Purpose : The retinal phenotype of popular mouse models mimicking ophthalmic diseases, such as the superoxide dismutase 1 (SOD1) knockout (KO) mouse model, has mainly been assessed by ex vivo histology and in vivo fundus photography. We used multifunctional optical coherence tomography (OCT) to characterize the retinas of SOD1 KO mice in vivo. Methods : The custom-made ophthalmoscope featured a combination of conventional OCT, polarization-sensitive OCT, and OCT angiography. Seven SOD1 KO ...
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    8. Polarization-sensitive imaging with simultaneous bright- and dark-field optical coherence tomography

      Polarization-sensitive imaging with simultaneous bright- and dark-field optical coherence tomography
      We present a polarization-sensitive (PS) extension for bright- and dark-field (BRAD) optical coherence tomography imaging. Using a few-mode fiber detection scheme, the light backscattered at different angles is separated, and the BRAD images of tissue scattering are generated. A calibration method to correct for the fiber birefringence is proposed. Since particle scattering profiles are polarization dependent, a PS detection extends the capabilities for investigating the scattering properties of biological tissues ...
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    9. Comparison of Intensity- and Polarization-based Contrast in Amyloid-beta Plaques as Observed by Optical Coherence Tomography

      Comparison of Intensity- and Polarization-based Contrast in Amyloid-beta Plaques as Observed by Optical Coherence Tomography
      One key hallmark of Alzheimers disease (AD) is the accumulation of extracellular amyloid-beta protein in cortical regions of the brain. For a definitive diagnosis of AD, post-mortem histological analysis, including sectioning and staining of different brain regions, is required. Here, we present optical coherence tomography (OCT) as a tissue-preserving imaging modality for the visualization of amyloid-beta plaques and compare their contrast in intensity- and polarization-sensitive (PS) OCT. Human brain samples ...
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    10. Investigating spontaneous retinal venous pulsation using Doppler optical coherence tomography

      Investigating spontaneous retinal venous pulsation using Doppler optical coherence tomography
      We demonstrate the advantages of optical coherence tomography (OCT) imaging for investigation of spontaneous retinal venous pulsation (SRVP). The pulsatile changes in venous vessel caliber are analyzed qualitatively and quantitatively using conventional intensity-based OCT as well as the functional extension Doppler OCT (DOCT). Single-channel and double-channel line scanning protocols of our multi-channel OCT prototype are employed to investigate venous pulsatile caliber oscillations as well as venous flow pulsatility in the ...
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    11. Mapping of Corneal Layer Thicknesses With Polarization-Sensitive Optical Coherence Tomography Using a Conical Scan Pattern

      Mapping of Corneal Layer Thicknesses With Polarization-Sensitive Optical Coherence Tomography Using a Conical Scan Pattern
      Purpose : We demonstrate segmentation and mapping of corneal layers (epithelium, Bowman's layer, and stroma) across the entire cornea (limbus to limbus), using additional contrast provided by polarization-sensitive optical coherence tomography (PS-OCT) and analyze the reproducibility of the procedure. Methods : A custom built PS-OCT system operating at 1045 nm central wavelength with conical scanning was used for image acquisition. Conical scanning allows for almost perpendicular beam incidence on the corneal ...
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    12. 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 ...
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    13. Assessment of pathological features in Alzheimer’s disease brain tissue with a large field-of-view visible-light optical coherence microscope

      Assessment of pathological features in Alzheimer’s disease brain tissue with a large field-of-view visible-light optical coherence microscope
      We implemented a wide field-of-view visible-light optical coherence microscope (OCM) for investigating ex-vivo brain tissue of patients diagnosed with Alzheimers disease (AD) and of a mouse model of AD. A submicrometer axial resolution in tissue was achieved using a broad visible light spectrum. The use of various objective lenses enabled reaching micrometer transversal resolution and the acquisition of images of microscopic brain features, such as cell structures, vessels, and white ...
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    14. Beyond backscattering: optical neuroimaging by BRAD

      Beyond backscattering: optical neuroimaging by BRAD
      Optical coherence tomography (OCT) is a powerful technology for rapid volumetric imaging in biomedicine. The bright field imaging approach of conventional OCT systems is based on the detection of directly backscattered light, thereby waiving the wealth of information contained in the angular scattering distribution. Here we demonstrate that the unique features of few-mode fibers (FMF) enable simultaneous bright and dark field (BRAD) imaging for OCT. As backscattered light is picked ...
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    15. Adaptable switching schemes for time-encoded multichannel optical coherence tomography

      Adaptable switching schemes for time-encoded multichannel optical coherence tomography
      We introduce the approach of variable time encoding for multichannel optical coherence tomography (OCT). High-speed fiber optical switches are applied for sequential sample arm switching to enable quasisimultaneous image acquisition from three different orientation angles. In comparison with previous multichannel OCT (using simultaneous sample illumination), time-encoded multichannel OCT has no need for division of illumination power among the respective channels to satisfy laser safety requirements. Especially for ophthalmic applicationsin particular ...
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    16. Optical Coherence Tomography for Brain Imaging (Book Chapter)

      Optical Coherence Tomography for Brain Imaging (Book Chapter)
      Optical coherence tomography (OCT) is an imaging technique based on the detection of light back-reflected or backscattered by tissue. Based on the principles of low-coherence interferometry, OCT provides rapid volumetric imaging with micrometer-scale resolution. OCT has been massively successful in ophthalmology where it became a routine tool for retinal diagnostics. In recent years, however, OCT has also been applied to other fields includingamongst otherscardiovascular imaging, endoscopy of the gastrointestinal tract ...
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      Mentions: Bernhard Baumann
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  2. About Bernhard Baumann

    Bernhard Baumann

    Bernhard Baumann was born in Vienna, Austria in 1981. He received his Masters in Physics from the University of Vienna in 2006. From 2006 to 2009, Bernhard worked on his doctoral studies under supervision of Prof. Christoph K. Hitzenberger at the Medical University of Vienna. He received a PhD in medical physics in 2009. In 2010, he joined the groups of Prof. James G. Fujimoto at the Research Laboratory of Electronics at the Massachusetts Institute of Technology and Dr. Jay S. Duker at New England Eye Center at Tufts University for a joint post-doctoral fellowship. Since his return to Vienna in 2012, Bernhard has been working as a post-doc at the Medical University of Vienna