1. Articles from rainer leitgeb

    1-14 of 14
    1. Ultra-high-resolution SD-OCM imaging with a compact polarization-aligned 840 nm broadband combined-SLED source

      Ultra-high-resolution SD-OCM imaging with a compact polarization-aligned 840 nm broadband combined-SLED source

      We analyze the influence of intrinsic polarization alignment on image quality and axial resolution employing a broadband 840 nm light source with an optical bandwidth of 160 nm and an output power of 12 mW tailored for spectral-domain optical coherence microscopy (SD-OCM) applications. Three superluminescent diodes (SLEDs) are integrated into a 14-pin butterfly module using a free-space micro-optical bench architecture, maintaining a constant polarization state across the full spectral output. We demonstrate superior imaging performance in comparison to traditionally coupled-SLED broadband light sources in a teleost model organism in-vivo .

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    2. Functional optical coherence tomography and photoacoustic microscopy imaging for zebrafish larvae

      Functional optical coherence tomography and photoacoustic microscopy imaging for zebrafish larvae

      We present a dual modality functional optical coherence tomography and photoacoustic microscopy (OCT-PAM) system. The photoacoustic modality employs an akinetic optical sensor with a large imaging window. This imaging window enables direct reflection mode operation, and a seamless integration of optical coherence tomography (OCT) as a second imaging modality. Functional extensions to the OCT-PAM system include Doppler OCT (DOCT) and spectroscopic PAM (sPAM). This functional and non-invasive imaging system is applied to image zebrafish larvae, demonstrating its capability to extract both morphological and hemodynamic parameters in vivo in small animals, which are essential and critical in preclinical imaging for physiological ...

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    3. Changes in Retinal Blood Flow in Response to an Experimental Increase in IOP in Healthy Participants as Assessed With Doppler Optical Coherence Tomography

      Changes in Retinal Blood Flow in Response to an Experimental Increase in IOP in Healthy Participants as Assessed With Doppler Optical Coherence Tomography

      Purpose : Blood flow autoregulation is an intrinsic mechanism of the healthy retinal vasculature to keep blood flow constant when ocular perfusion pressure (OPP) is changed. In the present study, we set out to investigate retinal blood flow in response to an experimental decrease in OPP in healthy participants using Doppler optical coherence tomography. Methods : Fifteen healthy participants aged between 22 and 31 years (mean, 27 ± 3 years) were included in the present open study. IOP was increased stepwise via the suction cup method to induce a decrease in OPP. Retinal blood flow in arteries and veins was assessed using a ...

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    4. Post Doc Position for Optical Coherence Tomography at the Medical University Vienna

      Post Doc Position for Optical Coherence Tomography at the Medical University Vienna

      A PostDoc position is available from March 1, 2020 at the Center for Medical Physics and Biomedical Engineering, Medical University of Vienna. We offer a research position in the field of biomedical imaging with strong interdisciplinary collaboration. Our research group is developing novel coherent biomedical imaging methods based on parallel OCT and digital adaptive optics 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 processing, as well as hands-on experience in modern biomedical optics ...

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    5. Combination of High-Resolution Optical Coherence Tomography and Raman Spectroscopy for Improved Staging and Grading in Bladder Cancer

      Combination of High-Resolution Optical Coherence Tomography and Raman Spectroscopy for Improved Staging and Grading in Bladder Cancer

      We present a combination of optical coherence tomography (OCT) and Raman spectroscopy (RS) for improved diagnosis and discrimination of different stages and grades of bladder cancer ex vivo by linking the complementary information provided by these two techniques. Bladder samples were obtained from biopsies dissected via transurethral resection of the bladder tumor (TURBT). As OCT provides structural information rapidly, it was used as a red-flag technology to scan the bladder wall for suspicious lesions with the ability to discriminate malignant tissue from healthy urothelium. Upon identification of degenerated tissue via OCT, RS was implemented to determine the molecular characteristics via ...

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    6. Twenty-five years of optical coherence tomography: the paradigm shift in sensitivity and speed provided by Fourier domain OCT

      Twenty-five years of optical coherence tomography: the paradigm shift in sensitivity and speed provided by Fourier domain OCT

      Optical coherence tomography (OCT) has become one of the most successful optical technologies implemented in medicine and clinical practice mostly due to the possibility of non-invasive and non-contact imaging by detecting back-scattered light. OCT has gone through a tremendous development over the past 25 years. From its initial inception in 1991 [Science 254 , 1178 (1991)] it has become an indispensable medical imaging technology in ophthalmology. Also in fields like cardiology and gastro-enterology the technology is envisioned to become a standard of care. A key contributor to the success of OCT has been the sensitivity and speed advantage offered by Fourier ...

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    7. Visualization of micro-capillaries using optical coherence tomography angiography with and without adaptive optics

      Visualization of micro-capillaries using optical coherence tomography angiography with and without adaptive optics

      The purpose of this work is to investigate the benefits of adaptive optics (AO) technology for optical coherence tomography angiography (OCTA). OCTA has shown great potential in non-invasively enhancing the contrast of vessels and small capillaries. Especially the capability of the technique to visualize capillaries with a lateral extension that is below the transverse resolution of the system opens unique opportunities in diagnosing retinal vascular diseases. However, there are some limitations of this technology such as shadowing and projection artifacts caused by overlying vasculature or the inability to determine the true extension of a vessel. Thus, the evaluation of the ...

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    8. 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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    9. Systems and methods for sub-aperture based aberration measurement and correction in interferometric imaging

      Systems and methods for sub-aperture based aberration measurement and correction in interferometric imaging

      Systems and methods for sub-aperture correlation based wavefront measurement in a thick sample and correction as a post processing technique for interferometric imaging to achieve near diffraction limited resolution are described. Theory, simulation and experimental results are presented for the case of full field interference microscopy. The inventive technique can be applied to any coherent interferometric imaging technique and does not require knowledge of any system parameters. In one embodiment of the present invention, a fast and simple way to correct for defocus aberration is described. A variety of applications for the inventive method are presented.

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    10. Interferometric sample measurement

      Interferometric sample measurement

      A device for the interferometric measurement of a sample, in particular the eye, including an interferometer arrangement with a first measurement beam path, through which a measurement beam falls onto the sample, and a first reference beam path, through which a reference beam runs, which is applied to the measuring beam for interference. The interferometer arrangement includes a second measuring beam path and/or second reference beam path. The optical path lengths of the second measuring beam path and/or second reference beam path are different from one of the first beam paths. The wave length difference is selected according ...

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    11. Precise Thickness Measurements of Bowman's Layer, Epithelium, and Tear Film

      Precise Thickness Measurements of Bowman's Layer, Epithelium, and Tear Film

      Purpose. To visualize corneal microstructure such as tear film, epithelium, and Bowman's layer in three dimensions with spectral domain optical coherence tomography (SDOCT) exhibiting 1.3 [mu]m axial resolution at 100,000 A-scans/s. This enables measurement of epithelial and Bowman layer thickness across an area of 8.4 mm x 8.4 mm and measuring the tear film thickness at the central cornea.Methods. We designed a high-performance SDOCT system, which uses a broad bandwidth TiSapph Laser and a high-speed complementary metal-oxide-semiconductor detector technology, providing a resolution in tissue of 1.3 [mu]m and an acquisition ...

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    12. Apparatus and method for interferometric measurement of a sample

      Apparatus and method for interferometric measurement of a sample
      A device for the interferometric measurement of a sample, in particular the eye, including an interferometer arrangement with a first measurement beam path, through which a measurement beam falls onto the sample, and a first reference beam path, through which a reference beam runs, which is applied to the measuring beam for interference. The interferometer arrangement includes a second measuring beam path and/or second reference beam path. The optical path lengths of the second measuring beam path and/or second reference beam path are different from one of the first beam paths. The wave length difference is selected according ...
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    13. Introduction: feature issue on In Vivo Microcirculation Imaging

      Introduction: feature issue on In Vivo Microcirculation Imaging
      The editors introduce the Biomedical Optics Express feature issue, “In Vivo Microcirculation Imaging,” which includes 14 contributions from the biomedical optics community, covering such imaging techniques as optical coherence tomography, photoacoustic microscopy, laser Doppler /speckle imaging, and near infrared spectroscopy and fluorescence imaging.
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    14. DUAL BEAM HETERODYNE FOURIER DOMAIN OPTICAL COHERENCE TOMOGRAPHY (WO 2008/087613)

      DUAL BEAM HETERODYNE FOURIER DOMAIN OPTICAL COHERENCE TOMOGRAPHY (WO 2008/087613)

      The present invention relates to an apparatus and a method combining achromatic complex FDOCT signal reconstruction with a common path and dual beam configuration. The complex signal reconstruction allows resolving the complex ambiguity of the Fourier transform and to enhance the achievable depth range by a factor of two. The dual beam configuration shares the property of high phase stability with common path FDOCT. This is of importance for a proper complex signal reconstruction and is in particular useful in combination with handheld probes such as in endoscopy and catheter applications. The advantages of the present invention are in particular ...

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    1-14 of 14
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    1. (14 articles) Rainer A. Leitgeb
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    3. (5 articles) Wolfgang Drexler
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    DUAL BEAM HETERODYNE FOURIER DOMAIN OPTICAL COHERENCE TOMOGRAPHY (WO 2008/087613) Introduction: feature issue on In Vivo Microcirculation Imaging Apparatus and method for interferometric measurement of a sample Precise Thickness Measurements of Bowman's Layer, Epithelium, and Tear Film Interferometric sample measurement Systems and methods for sub-aperture based aberration measurement and correction in interferometric imaging Comprehensive vascular imaging using optical coherence tomography-based angiography and photoacoustic tomography Visualization of micro-capillaries using optical coherence tomography angiography with and without adaptive optics Twenty-five years of optical coherence tomography: the paradigm shift in sensitivity and speed provided by Fourier domain OCT Post Doc Position for Optical Coherence Tomography at the Medical University Vienna Optical coherence tomography features of neovascularization in proliferative diabetic retinopathy: a systematic review Retinal microvascular metrics in untreated essential hypertensives using optical coherence tomography angiography