1. Articles from Gereon Hüttmann

    1-24 of 44 1 2 »
    1. Dynamic contrast in scanning microscopic OCT

      Dynamic contrast in scanning microscopic OCT

      While optical coherence tomography (OCT) provides a resolution down to 1 micrometer it has difficulties to visualize cellular structures due to a lack of scattering contrast. By evaluating signal fluctuations, a significant contrast enhancement was demonstrated using time-domain full-field OCT (FF-OCT), which makes cellular and subcellular structures visible. The putative cause of the dynamic OCT signal is ATP-dependent motion of cellular structures in a sub-micrometer range, which provides histology-like contrast. Here we demonstrate dynamic contrast with a scanning frequency-domain OCT (FD-OCT). Given the inherent sectional imaging geometry, scanning FD-OCT provides depth-resolved images across tissue layers, a perspective known from histopathology ...

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    2. Intravital microscopic optical coherence tomography imaging to assess mucus mobilizing interventions for muco-obstructive lung disease in mice

      Intravital microscopic optical coherence tomography imaging to assess mucus mobilizing interventions for muco-obstructive lung disease in mice

      Airway mucus obstruction is a hallmark of chronic lung diseases such as cystic fibrosis, asthma and COPD, and the development of more effective mucus mobilizing therapies remains an important unmet need for patients with these muco-obstructive lung diseases. However, methods for sensitive visualization and quantitative assessment of immediate effects of therapeutic interventions on mucus clearance in vivo are lacking. In this study, we determined if newly developed high-speed microscopic optical coherence tomography (mOCT) is sensitive to detect and compare in vivo effects of inhaled isotonic saline, hypertonic saline and bicarbonate on mucus mobilization and clearance in Scnn1b -transgenic mice with ...

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    3. Investigation of cell dynamics in 3D cell spheroids and cell interaction with 3D printed scaffolds by mOCT

      Investigation of cell dynamics in 3D cell spheroids and cell interaction with 3D printed scaffolds by mOCT

      Optical coherence tomography is a non-invasive and label-free imaging modality based on the detection of backscattered light in samples. As microscopic OCT (mOCT) combines high axial and lateral resolution, an investigation of biological and printed samples at subcellular level is feasible. The additional excellent depth resolution enables mOCT to be a suitable quality control of 3D printed samples. The use of speckle variance adds information about cell viability. Here we present the feasibility of investigating cell viability within a cell spheroid and monitoring the cell interaction with bioprinted scaffolds using mOCT.

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    4. Computational adaptive optics for optical coherence tomography using multiple randomized subaperture correlations

      Computational adaptive optics for optical coherence tomography using multiple randomized subaperture correlations

      Computational adaptive optics (CAO) is emerging as a viable alternative to hardware-based adaptive optics—in particular when applied to optical coherence tomography of the retina. For this technique, algorithms are required that detect wavefront errors precisely and quickly. Here we propose an extension of the frequently used subaperture image correlation. By applying this algorithm iteratively and, more importantly, comparing each subaperture not to the central subaperture but to several randomly selected apertures, we improved aberration correction. Since these modifications only slightly increase the run time of the correction, we believe this method can become the algorithm of choice for many ...

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    5. Segmentation of mouse skin layers in optical coherence tomography image data using deep convolutional neural networks

      Segmentation of mouse skin layers in optical coherence tomography image data using deep convolutional neural networks

      Optical coherence tomography (OCT) enables the non-invasive acquisition of high-resolution three-dimensional cross-sectional images at micrometer scale and is mainly used in the field of ophthalmology for diagnosis as well as monitoring of eye diseases. Also in other areas, such as dermatology, OCT is already well established. Due to its non-invasive nature, OCT is also employed for research studies involving animal models. Manual evaluation of OCT images of animal models is a challenging task due to the lack of imaging standards and the varying anatomy between models. In this paper, we present a deep learning algorithm for the automatic segmentation of ...

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    6. Optimization-based vessel segmentation pipeline for robust quantification of capillary networks in skin with optical coherence tomography angiography

      Optimization-based vessel segmentation pipeline for robust quantification of capillary networks in skin with optical coherence tomography angiography

      Optical coherence tomography angiography (OCTA) provides in-vivo images of microvascular perfusion in high resolution. For its application to basic and clinical research, an automatic and robust quantification of the capillary architecture is mandatory. Only this makes it possible to reliably analyze large amounts of image data, to establish biomarkers, and to monitor disease developments. However, due to its optical properties, OCTA images of skin often suffer from a poor signal-to-noise ratio and contain imaging artifacts. Previous work on automatic vessel segmentation in OCTA mostly focuses on retinal and cerebral vasculature. Its applicability to skin and, furthermore, its robustness against imaging ...

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    7. Artifacts in speckle tracking and multi-aperture Doppler OCT imaging of lateral motion

      Artifacts in speckle tracking and multi-aperture Doppler OCT imaging of lateral motion

      In optical coherence tomography (OCT), lateral motion is determined either by speckle tracking or by multi-aperture Doppler OCT. Here we show that both methods may provide incorrect results because, outside the focal plane, non-uniform axial motion is misinterpreted as lateral motion. First, we demonstrate the existence of this artifact by means of a simulation for speckle tracking. Then the physical origin of the artifact and its mathematical relation to defocus and axial motion are explained. It is shown that speckle tracking and multi-aperture Doppler OCT are equally affected by the artifact, which has a considerable effect, even for a defocus ...

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    8. Method for filtering reflexes in full-field setups for ophthalmologic imaging by separated illumination and detection apertures

      Method for filtering reflexes in full-field setups for ophthalmologic imaging by separated illumination and detection apertures

      A parallel detecting optical coherence tomography (OCT) setup and method, in which the light paths of the illumination of the sample and of the detection of the backscattered light do not use the same apertures. The separation of illumination and detection apertures filters these disturbing reflexes from the backscattered light of the sample and significantly increases image quality.

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    9. Simple approach for aberration-corrected OCT imaging of the human retina

      Simple approach for aberration-corrected OCT imaging of the human retina

      Aberration-corrected imaging of human photoreceptor cells, whether hardware or software based, presently requires a complex and expensive setup. Here we use a simple and inexpensive off-axis full-field time-domain optical coherence tomography (OCT) approach to acquire volumetric data of an in vivo human retina. Full volumetric data are recorded in 1.3 s. After computationally correcting for aberrations, single photoreceptor cells were visualized. In addition, the numerical correction of ametropia is demonstrated. Our implementation of full-field optical coherence tomography combines a low technical complexity with the possibility for computational image correction.

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    10. High-speed fiber scanning endoscope for volumetric multi-megahertz optical coherence tomography

      High-speed fiber scanning endoscope for volumetric multi-megahertz optical coherence tomography

      We present a forward-viewing fiber scanning endoscope (FSE) for high-speed volumetric optical coherence tomography (OCT). The reduction in size of the probe was achieved by substituting the focusing optics by an all-fiber-based imaging system which consists of a combination of scanning single-mode fibers, a glass spacer, made from a step-index multi-mode fiber, and a gradient-index fiber. A lateral resolution of 11 μm was achieved at a working distance of 1.2 mm. The newly designed piezo-based FSE has an outer diameter of 1.6 mm and a rigid length of 13.5 mm. By moving the whole imaging optic in ...

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    11. Interferometric detection of 3D motion using computational subapertures in optical coherence tomography

      Interferometric detection of 3D motion using computational subapertures in optical coherence tomography

      Doppler optical coherence tomography (OCT) quantifies axial motion with high precision, whereas lateral motion cannot be detected by a mere evaluation of phase changes. This problem was solved by the introduction of three-beam Doppler OCT, which, however, entails a high experimental effort. Here, we present the numerical analogue to this experimental approach. Phase-stable complex-valued OCT datasets, recorded with full-field swept-source OCT, are filtered in the Fourier domain to limit imaging to different computational subapertures. These are used to calculate all three components of the motion vector with interferometric precision. As known from conventional Doppler OCT for axial motion only, the ...

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    12. Novel endoscope with increased depth of field for imaging human nasal tissue by microscopic optical coherence tomography

      Novel endoscope with increased depth of field for imaging human nasal tissue by microscopic optical coherence tomography

      Intravital microscopy (IVM) offers the opportunity to visualize static and dynamic changes of tissue on a cellular level. It is a valuable tool in research and may considerably improve clinical diagnosis. In contrast to confocal and non-linear microscopy, optical coherence tomography (OCT) with microscopic resolution (mOCT) provides intrinsically cross-sectional imaging. Changing focus position is not needed, which simplifies especially endoscopic imaging. For in-vivo imaging, here we are presenting endo-microscopic OCT (emOCT). A graded-index-lens (GRIN) based 2.75 mm outer diameter rigid endoscope is providing 1.5 – 2 µm nearly isotropic resolution over an extended field of depth. Spherical and chromatic ...

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    13. Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography

      Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography

      In their latest publication on retinal pulse wave velocity measurement using optical co-herence tomography (OCT), Qian Li et al. propose a method to determine the pulse wave velocity in retinal arteries and veins [1]. This should enable a non-invasive determination of biomechanical properties of the vessel network, particularly the elasticity of the vessel walls [2].

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    14. Label-Free In Vivo Imaging of Corneal Lymphatic Vessels Using Microscopic Optical Coherence Tomography

      Label-Free In Vivo Imaging of Corneal Lymphatic Vessels Using Microscopic Optical Coherence Tomography

      Purpose : Corneal neovascularization, in particular lymphangiogenesis, is a limiting factor in corneal transplant survival. Novel treatment approaches focus on (selective) inhibition and regression of lymphatic vessels. Imaging clinically invisible corneal lymphatic vessels is a prerequisite for these strategies. Using a murine model, this study investigates whether corneal lymphatic vessels can be imaged using microscopic optical coherence tomography (mOCT). Methods : Corneal neovascularization was induced by intrastromal placement of 11.0 nylon sutures in one eye of BALB/c mice. After 2 weeks, cross-sectional images and volumes of the corneas with a 0.5 mm lateral and axial field of view were ...

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    15. An Approach for Needle Based Optical Coherence Elastography Measurements

      An Approach for Needle Based Optical Coherence Elastography Measurements

      While navigation and interventional guidance are typically based on image data, the images do not necessarily reflect mechanical tissue properties. Optical coherence elastography (OCE) presents a modality with high sensitivity and very high spatial and temporal resolution. However, OCE has a limited field of view of only 2–5 mm depth. We present a side-facing needle probe to image externally induced shear waves from within soft tissue. A first method of quantitative needle-based OCE is provided. Using a time of flight setup, we establish the shear wave velocity and estimate the tissue elasticity. For comparison, an external scan head is ...

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    16. Reduction of frame rate in full-field swept-source optical coherence tomography by numerical motion correction [Invited]

      Reduction of frame rate in full-field swept-source optical coherence tomography by numerical motion correction [Invited]

      Full-field swept-source optical coherence tomography (FF-SS-OCT) was recently shown to allow new and exciting applications for imaging the human eye that were previously not possible using current scanning OCT systems. However, especially when using cameras that do not acquire data with hundreds of kHz frame rate, uncorrected phase errors due to axial motion of the eye lead to a drastic loss in image quality of the reconstructed volumes. Here we first give a short overview of recent advances in techniques and applications of parallelized OCT and finally present an iterative and statistical algorithm that estimates and corrects motion-induced phase errors ...

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    17. In-vivo retinal imaging with off-axis full-field time-domain optical coherence tomography

      In-vivo retinal imaging with off-axis full-field time-domain optical coherence tomography

      With a simple setup, mainly composed of a low coherence light source and a camera, full-field optical coherence tomography (FF-OCT) allows volumetric tissue imaging. However, fringe washout constrains its use in retinal imaging. Here, we present a novel motion-insensitive approach to FF-OCT, which introduces path-length differences between the reference and the sample light in neighboring pixels using an off-axis reference beam. The temporal carrier frequency in scanned time-domain OCT is replaced by a spatial carrier frequency. Volumetric in-vivo FF-OCT measurements of the human retina were acquired in only 1.3 s, comparable to the acquisition times of current clinically used ...

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    18. Feature Of The Week 10/25/2015: Imaging Pulse Wave Propagation in Human Retina using Full-Field Swept-Source OCT

      Feature Of The Week 10/25/2015: Imaging Pulse Wave Propagation in Human Retina using Full-Field Swept-Source OCT

      We demonstrate a new noninvasive method to assess biomechanical properties of the retinal vascular system. Phase-sensitive full-field swept-source optical coherence tomography (PhS-FF-SS-OCT) is used to investigate retinal vascular dynamics at unprecedented temporal resolution. The motion of retinal tissue that is induced by expansion of the vessels therein is measured with an accuracy of about 10 nm. The pulse shapes of arterial and venous pulsations, their temporal delays, as well as the frequency-dependent pulse propagation through the capillary bed, are determined. For the first time, imaging speed and motion sensitivity are sufficient for a direct measurement of pulse waves propagating with ...

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    19. Imaging pulse wave propagation in human retinal vessels using full-field swept-source optical coherence tomography

      Imaging pulse wave propagation in human retinal vessels using full-field swept-source optical coherence tomography

      We demonstrate a new noninvasive method to assess biomechanical properties of the retinal vascular system. Phase-sensitive full-field swept-source optical coherence tomography (PhS-FF-SS-OCT) is used to investigate retinal vascular dynamics at unprecedented temporal resolution. The motion of retinal tissue that is induced by expansion of the vessels therein is measured with an accuracy of about 10 nm. The pulse shapes of arterial and venous pulsations, their temporal delays, as well as the frequency-dependent pulse propagation through the capillary bed, are determined. For the first time, imaging speed and motion sensitivity are sufficient for a direct measurement of pulse waves propagating with ...

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    20. Future Prospects: Assessment of Intraoperative Optical Coherence Tomography in Ab Interno Glaucoma Surgery

      Future Prospects: Assessment of Intraoperative Optical Coherence Tomography in Ab Interno Glaucoma Surgery

      Purpose : Ab interno glaucoma surgery , such as trabecular aspiration or ab interno trabeculotomy, has been introduced as an alternative, non-filtering procedure to lower intraocular pressure in glaucoma patients. The purpose of the present study was to assess the feasibility of intraoperative spectral domain optical coherence tomography (iOCT) for improving ab interno glaucoma surgery . Materials and Methods : Intraoperative optical coherence tomography was performed to visualize the anterior chamber angle, the aspiration canula during trabecular aspiration, and the trabectome device during ab interno trabeculotomy. A commercially available 840-nm iOCT was used in a clinical setting, a 1310-nm spectral-domain OCT in an experimental ...

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    21. Optimizing Descemet Membrane Endothelial Keratoplasty Using Intraoperative Optical Coherence Tomography

      Optimizing Descemet Membrane Endothelial Keratoplasty Using Intraoperative Optical Coherence Tomography

      Importance Descemet membrane endothelial keratoplasty (DMEK) is a challenging procedure for the surgeon, particularly because of deficient visibility of the delicate tissue due to the natural en face view through the operating microscope. A cross-sectional view would greatly enhance intraoperative overview and enable the surgeon to better control the procedure. Objective To retrospectively analyze the use of intraoperative optical coherence tomography (iOCT) for improving the safety of DMEK. Design Intraoperative OCT during DMEK was performed in 26 eyes of 26 patients. We retrospectively analyzed imaging and video data. Setting Department of Ophthalmology, University of Cologne. Participants Seven men and 19 ...

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    22. Coronal in vivo forward-imaging of rat brain morphology with an ultra-small optical coherence tomography fiber probe

      Coronal in vivo forward-imaging of rat brain morphology with an ultra-small optical coherence tomography fiber probe

      A well-established navigation method is one of the key conditions for successful brain surgery: it should be accurate, safe and online operable. Recent research shows that optical coherence tomography (OCT) is a potential solution for this application by providing a high resolution and small probe dimension. In this study a fiber-based spectral-domain OCT system utilizing a super-luminescent-diode with the center wavelength of 840 nm providing 14.5 μm axial resolution was used. A composite 125 μm diameter detecting probe with a gradient index (GRIN) fiber fused to a single mode fiber was employed. Signals were reconstructed into grayscale images by ...

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    1-24 of 44 1 2 »
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  2. Topics in the News

    1. (44 articles) Gereon Hüttmann
    2. (38 articles) University of Lübeck
    3. (14 articles) Thorlabs
    4. (8 articles) Hendrik Spahr
    5. (5 articles) Reginald Birngruber
    6. (3 articles) University of Cologne
    7. (3 articles) Universität Rostock
    8. (2 articles) Massachusetts General Hospital
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    10. (1 articles) University of Freiburg
    11. (1 articles) Medical University of Vienna
    12. (1 articles) Harbin Medical University
    13. (1 articles) Université Pierre et Marie Curie
    14. (1 articles) University of Erlangen
    15. (1 articles) Wolfgang Drexler
    16. (1 articles) Adrian G. Podoleanu
    17. (1 articles) Mengyang Liu
    18. (1 articles) Bo Yu
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    Optical coherence tomography allows for the reliable identification of laryngeal epithelial dysplasia and for precise biopsy: A clinicopathological study of 61 patients undergoing microlaryngoscopy In vivo Fourier-domain full-field OCT of the human retina with 1.5 million A-lines/s Optical coherence tomography (OCT) for early diagnosis of tumors and online-control of photodynamic therapy (PDT) Comparison of fast swept source full-field OCT with conventional scanning OCT Holoscopy: holographic optical coherence tomography 3D OPTICAL IMAGING: Holoscopy makes ultrafast lensless imaging of scattering tissues possible Feature Of The Week 10/25/2015: Imaging Pulse Wave Propagation in Human Retina using Full-Field Swept-Source OCT Changes in the Retinal Microvasculature Measured Using Optical Coherence Tomography Angiography According to Age Direct en-face, speckle-reduced images using angular-compounded Master-Slave optical coherence tomography A case report of a recurrent early and late Bioresorbable vascular scaffold thrombosis: serial angiography and optical coherence tomography findings Optical coherence tomography angiography as a novel approach to contactless evaluation of sublingual microcirculation: A proof of principle study Functional optical coherence tomography and photoacoustic microscopy imaging for zebrafish larvae