1. Wolfgang Drexler

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    1. Mentioned In 148 Articles

    2. Towards ultrahigh resolution OCT based endoscopical pituitary gland and adenoma screening: a performance parameter evaluation

      Towards ultrahigh resolution OCT based endoscopical pituitary gland and adenoma screening: a performance parameter evaluation
      Ultrahigh resolution optical coherence tomography (UHR-OCT) for differentiating pituitary gland versus adenoma tissue has been investigated for the first time, indicating more than 80% accuracy. For biomarker identification, OCT images of paraffin embedded tissue are correlated to histopathological slices. The identified biomarkers are verified on fresh biopsies. Additionally, an approach, based on resolution modified UHR-OCT ex vivo data, investigating optical performance parameters for the realization in an in vivo endoscope ...
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    3. Three-dimensional composition of the photoreceptor cone layers in healthy eyes using adaptive-optics optical coherence tomography (AO-OCT)

      Three-dimensional composition of the photoreceptor cone layers in healthy eyes using adaptive-optics optical coherence tomography (AO-OCT)
      Purpose To assess the signal composition of cone photoreceptors three-dimensionally in healthy retinas using adaptive optics optical coherence tomography (AO-OCT). Methods Study population. Twenty healthy eyes of ten subjects (age 23 to 67). Procedures. After routine ophthalmological assessments, eyes were examined using AO-OCT. Three-dimensional volumes were acquired at 2.5 and 6.5 foveal eccentricity in four main meridians (superior, nasal, inferior, temporal). Cone densities and signal compositions were investigated ...
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    4. Toward optical coherence tomography on a chip: in vivo three-dimensional human retinal imaging using photonic integrated circuit-based arrayed waveguide gratings

      Toward optical coherence tomography on a chip: in vivo three-dimensional human retinal imaging using photonic integrated circuit-based arrayed waveguide gratings
      In this work, we present a significant step toward in vivo ophthalmic optical coherence tomography and angiography on a photonic integrated chip. The diffraction gratings used in spectral-domain optical coherence tomography can be replaced by photonic integrated circuits comprising an arrayed waveguide grating. Two arrayed waveguide grating designs with 256 channels were tested, which enabled the first chip-based optical coherence tomography and angiography in vivo three-dimensional human retinal measurements. Design ...
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    5. Three-dimensional assessment of para- and perifoveal photoreceptor densities and the impact of meridians and age in healthy eyes with adaptive-optics optical coherence tomography (AO-OCT)

      Three-dimensional assessment of para- and perifoveal photoreceptor densities and the impact of meridians and age in healthy eyes with adaptive-optics optical coherence tomography (AO-OCT)
      An adaptive optics optical coherence tomography (AO-OCT) system is used to assess sixty healthy eyes of thirty subjects (age 22 to 75) to evaluate how the outer retinal layers, foveal eccentricity and age effect the mean cone density. The cone mosaics of different retinal planes (the cone inner segment outer segment junction (IS/OS), the cone outer segment combined with the IS/OS (ISOS+), the cone outer segment tips (COST ...
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    6. Ultra-high-resolution 3D optical coherence tomography reveals inner structures of human placenta-derived trophoblast organoids

      Ultra-high-resolution 3D optical coherence tomography reveals inner structures of human placenta-derived trophoblast organoids
      Objective: 3D optical coherence tomography (OCT) is used for analyses of human placenta organoids in situ without sample preparation. Methods: The trophoblast organoids analyzed were derived from primary human trophoblast. In this study a custom made ultra-high-resolution spectral domain OCT system with uniform spatial and axial resolution of 2.48 m in organoid tissue was used. The obtained OCT results align to differentiation status tested via quantitative polymerase chain reaction ...
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    7. Multi-channel swept source optical coherence tomography concept based on photonic integrated circuits

      Multi-channel swept source optical coherence tomography concept based on photonic integrated circuits
      In this paper, we present a novel concept for a multi-channel swept source optical coherence tomography (OCT) system based on photonic integrated circuits (PICs). At the core of this concept is a low-loss polarization dependent path routing approach allowing for lower excess loss compared to previously shown PIC-based OCT systems, facilitating a parallelization of measurement units. As a proof of concept for the low-loss path routing, a silicon nitride PIC-based ...
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      Mentions: Wolfgang Drexler
    8. 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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    9. 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 840nm light source with an optical bandwidth of 160nm and an output power of 12mW 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 ...
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    10. 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 ...
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    11. Morpho-molecular ex vivo detection and grading of non-muscle-invasive bladder cancer using forward imaging probe based multimodal optical coherence tomography and Raman spectroscop

      Morpho-molecular ex vivo detection and grading of non-muscle-invasive bladder cancer using forward imaging probe based multimodal optical coherence tomography and Raman spectroscop
      Non-muscle-invasive bladder cancer affects millions of people worldwide, resulting in significant discomfort to the patient and potential death. Today, cystoscopy is the gold standard for bladder cancer assessment, using white light endoscopy to detect tumor suspected lesion areas, followed by resection of these areas and subsequent histopathological evaluation. Not only does the pathological examination take days, but due to the invasive nature, the performed biopsy can result in significant harm ...
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    12. Measurement and visualization of stimulus-evoked tissue dynamics in mouse barrel cortex using phase-sensitive optical coherence tomography

      Measurement and visualization of stimulus-evoked tissue dynamics in mouse barrel cortex using phase-sensitive optical coherence tomography
      .... Povazay, H. Sattmann, P. Qiu, E. Anger, H. Reitsamer, S. Popov, J. R. Taylor, A. Unterhuber, P. Ahnelt, and W. Drexler, “Optophysiology: depth-resolved probing of retinal physiology with functional ultrahigh-resolution...
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    13. Comparison of optical coherence tomography angiography and narrow-band imaging using a bimodal endoscope

      Comparison of optical coherence tomography angiography and narrow-band imaging using a bimodal endoscope
      We present coregistered images of tissue vasculature that allow a direct comparison between the performance of narrow-band imaging (NBI) and optical coherence tomography angiography (OCTA). Images were generated with a bimodal endomicroscope having a size of 152.43.3mm 3 ( l , w , h ) that combines two imaging channels. The white light imaging channel was used to perform NBI, the current gold standard for endoscopic visualization of vessels. The second channel ...
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    14. Histologic Correlation of Pig Retina Radial Stratification with Ultrahigh-Resolution Optical Coherence Tomography

      Histologic Correlation of Pig Retina Radial Stratification with Ultrahigh-Resolution Optical Coherence Tomography
      purpose. To compare ultrahigh-resolution optical coherence tomography (OCT) cross-sectional images of the pig retina with histology, to evaluate the potential of ultrahigh-resolution OCT for enhanced visualization of intra- and subretinal structures. methods. Ultrahigh-resolution OCT images were acquired with 1.4-m axial 3-m transverse resolution from in vitro posterior eyecup preparations of the domestic pig. Frozen sections were obtained in precise alignment with OCT tomograms, by using major blood vessels as ...
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    15. Feature Of The Week 03/31/2019: Depth resolved label-free multimodal optical imaging platform to study morpho-molecular composition of tissue

      Feature Of The Week 03/31/2019: Depth resolved label-free multimodal optical imaging platform to study morpho-molecular composition of tissue
      We have developed a multimodal laser scanning microscope (LSM) platform combining optical coherence tomography (OCT), spectral focusing coherent anti-Stokes Raman scattering (SF-CARS), second harmonic generation (SHG) and two-photon excited fluorescence (TPF). Morphological, molecular and biochemical information from tissues can be collected in a non-invasive and label-free manner by merging ultra-fast Ti:sapphire lasers with well-developed optical imaging techniques. The combination of the proposed imaging modalities enables increased sensitivity and specificity ...
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  2. About Wolfgang Drexler

    Wolfgang Drexler

    Wolfgang Drexler was a Full Professor of Biomedical Imaging at the School of Optometry and Vision Sciences at Cardiff University, Wales, UK from 2006 to 2009. Since October 2009 he is a Full Professor of Medical Physics and the Head of the Center for Medical Physics and Biomedical Engineering at the Medical University of Vienna, Austria, Honorary Distinguished Professor at Cardiff University and is also Director of the Christian Doppler Laboratory. He is a member of the Austrian Academy of Science and has published more than 150 publications (including Nature Medicine and PNAS).

  3. Quotes

    1. State-of-the-art OCT technology has its limitations: it is bulky, the size of a desk top and quite expensive, costing anything in the region of €100, 000 per unit. It can detect abnormalities but at the present moment, compact, cost effective versions that can be used outside of hospitals and in private practice in a hand held mode do not exist...The core component of our OCTChip project targets the size of a 1 cent coin. It will reduce costs and is maintenance free. Hence retinal diseases like Diabetic Retinopathy and Glaucoma as well as other retina diseases that are worldwide leading causes for blindness might be diagnosed via screening with this cost-effective compact point-of-care version of OCT...OCTChip fosters wide spread use to visualise and quantify the retina in more definition, so we can diagnose diseases better, quicker, and cheaper.
      In Coin-Sized Scanner to Target Blindness
    2. Miniaturization of OCT-based imaging technology on integrated photonics enables a novel, unique generation of not only cost-effective, but also compact, robust and nearly maintenance-free handheld OCT systems...The partners of the BiopsyPen Project have exquisite complementary expertise to accomplish a significant step towards this ambitious goal.”
      In MedLumics Announces “BiopsyPen Project” with €3.6M EU in Funding; Initiative Aimed at New Clinical Applications for Optical Coherence Tomography
    3. Swept-source technology from Insight has the potential to revolutionize OCT in the future, especially regarding ease of use, flexibility, and unique OCT performance.
      In Akinetic all-semiconductor swept lasers boost OCT image quality
    4. Lasers and light-­‐based methods have long promised to deliver benefits to clinicians through faster, more accurate, more sensitive, and more cost-­‐effective diagnosis of cancer and other important diseases, but so far most optical diagnostic instruments are expensive, complex and have limited performance. A key reason for this is that the lasers and light sources they use, are adapted from other industrial and scientific applications, and have not been optimized for these new clinical uses. Now in FAMOS, we will develop and demonstrate the next generation of light sources to produce step changes in cost/performance that will trigger development of a whole new world of non-­‐invasive clinical diagnostic tools.
      In European Commission backs biophotonics ‘FAMOS’ consortium with €10.1M for project to develop new lasers for earlier, better diagnosis of major diseases
    5. We've passed acceptance and we're between elation and state of the art...I personally think that OCT will never replace any gold standard like histology or established imaging modalities, but it will be very important at generating information in the future...It provides you with more information for earlier diagnosis.
      In Optical coherence tomography: cellular and functional retinal imaging