1. Articles from Maria Gaertner

    1-20 of 20
    1. Optical Coherence Tomography (OCT) for Time-Resolved Imaging of Alveolar Dynamics in Mechanically Ventilated Rats

      Optical Coherence Tomography (OCT) for Time-Resolved Imaging of Alveolar Dynamics in Mechanically Ventilated Rats

      Though artificial ventilation is an essential life-saving treatment, the mechanical behavior of lung tissue at the alveolar level is still unknown. Therefore, we need to understand the tissue response during artificial ventilation at this microscale in order to develop new and more protective ventilation methods. Optical coherence tomography (OCT) combined with intravital microscopy (IVM) is a promising tool for visualizing lung tissue dynamics with a high spatial and temporal resolution in uninterruptedly ventilated rats. We present a measurement setup using a custom-made animal ventilator and a gating technique for data acquisition of time-resolved sequences.

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    2. Imaging of nanoparticle-labeled stem cells using magnetomotive optical coherence tomography, laser speckle reflectometry, and light microscopy

      Imaging of nanoparticle-labeled stem cells using magnetomotive optical coherence tomography, laser speckle reflectometry, and light microscopy

      Cell transplantation and stem cell therapy are promising approaches for regenerative medicine and are of interest to researchers and clinicians worldwide. However, currently, no imaging technique that allows three-dimensional in vivo inspection of therapeutically administered cells in host tissues is available. Therefore, we investigate magnetomotive optical coherence tomography (MM-OCT) of cells labeled with magnetic particles as a potential noninvasive cell tracking method. We develop magnetomotive imaging of mesenchymal stem cells for future cell therapy monitoring. Cells were labeled with fluorescent iron oxide nanoparticles, embedded in tissue-mimicking agar scaffolds, and imaged using a microscope setup with an integrated MM-OCT probe. Magnetic ...

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    3. Towards a comprehensive eye model for zebrafish retinal imaging using full range spectral domain optical coherence tomography

      Towards a comprehensive eye model for zebrafish retinal imaging using full range spectral domain optical coherence tomography

      In regenerative medicine, the zebrafish is a prominent animal model for studying degeneration and regeneration processes, e.g. of photoreceptor cells in the retina. By means of optical coherence tomography (OCT), these studies can be conducted over weeks using the same individual and hence reducing the variability of the results. To allow an improvement of zebrafish retinal OCT imaging by suitable optics, we developed a zebrafish eye model using geometrical data obtained by in vivo dispersion encoded full range OCT as well as a dispersion comprising gradient index (GRIN) lens model based on refractive index data found in the literature ...

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    4. Total liquid ventilation: a new approach to improve 3D OCT image quality of alveolar structures in lung tissue

      Total liquid ventilation: a new approach to improve 3D OCT image quality of alveolar structures in lung tissue

      Little is known about mechanical processes of alveolar tissue during mechanical ventilation. Optical coherence tomography (OCT) as a three-dimensional and high-resolution imaging modality can be used to visualize subpleural alveoli during artificial ventilation. The quality of OCT images can be increased by matching the refractive index inside the alveoli to the one of tissue via liquid-filling. Thereby, scattering loss can be decreased and higher penetration depth and tissue contrast can be achieved. We show the liquid-filling of alveolar structures verified by optical coherence tomography and intravital microscopy (IVM) and the advantages of index matching for OCT imaging of subpleural alveoli ...

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    5. High-resolution optical coherence tomography in mouse models of genetic and induced retinal degeneration

      High-resolution optical coherence tomography in mouse models of genetic and induced retinal degeneration

      For the study of disease mechanisms and the development of novel therapeutic strategies for retinal pathologies in human, rodent models play an important role. Nowadays, optical coherence tomography (OCT) allows three-dimensional investigation of retinal events over time. However, a detailed analysis of how different retinal degenerations are reflected in OCT images is still lacking in the biomedical field. Therefore, we use OCT to visualize retinal degeneration in specific mouse models in order to study disease progression in vivo and improve image interpretation of this noninvasive modality. We use a self-developed spectral domain OCT system for simultaneous dual-band imaging in the ...

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    6. Magnetomotive imaging of iron oxide nanoparticles as cellular contrast agents for optical coherence tomography

      Magnetomotive imaging of iron oxide nanoparticles as cellular contrast agents for optical coherence tomography

      Recent studies in animal models provided proof-of-principle evidence for cell transplantation as a potential future therapeutic approach for retinal pathologies in humans such as Retinitis pigmentosa or age-related macular degeneration. In this case, donor cells are injected into the eye in order to protect or replace degenerating photoreceptors or retinal pigment epithelium. However, currently there is no three-dimensional imaging technique available that allows tracking of cell migration and integration into the host tissue under in vivo conditions. Therefore, we investigate about magnetomotive optical coherence tomography (OCT) of substances labeled with iron oxide nanoparticles as a potential method for noninvasive, three-dimensional ...

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    7. Four-dimensional optical coherence tomography imaging of total liquid ventilated rats

      Four-dimensional optical coherence tomography imaging of total liquid ventilated rats

      Optical coherence tomography (OCT) can be utilized for the spatially and temporally resolved visualization of alveolar tissue and its dynamics in rodent models, which allows the investigation of lung dynamics on the microscopic scale of single alveoli. The findings could provide experimental input data for numerical simulations of lung tissue mechanics and could support the development of protective ventilation strategies. Real four-dimensional OCT imaging permits the acquisition of several OCT stacks within one single ventilation cycle. Thus, the entire four-dimensional information is directly obtained. Compared to conventional virtual four-dimensional OCT imaging, where the image acquisition is extended over many ventilation ...

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    8. Three-dimensional simultaneous optical coherence tomography and confocal fluorescence microscopy for investigation of lung tissue

      Three-dimensional simultaneous optical coherence tomography and confocal fluorescence microscopy for investigation of lung tissue

      Although several strategies exist for a minimal-invasive treatment of patients with lung failure, the mortality rate of acute respiratory distress syndrome still reaches 30% at minimum. This striking number indicates the necessity of understanding lung dynamics on an alveolar level. To investigate the dynamical behavior on a microscale, we used three-dimensional geometrical and functional imaging to observe tissue parameters including alveolar size and length of embedded elastic fibers during ventilation. We established a combined optical coherence tomography (OCT) and confocal fluorescence microscopy system that is able to monitor the distension of alveolar tissue and elastin fibers simultaneously within three dimensions ...

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    9. Feature Of The Week 5/20/12: Dresden University of Technology Investigates Precision Lung Dynamics Using Four-Dimensional OCT

      Feature Of The Week 5/20/12: Dresden University of Technology Investigates Precision Lung Dynamics Using Four-Dimensional OCT

      The treatment of urgent lung diseases, such as the acute respiratory distress syndrome and the acute lung injury, requires the development of protective ventilation strategies with the help of numerical simulations. For this purpose, information about the structure of lung tissue and its dynamics is required on an alveolar level. Optical coherence tomography (OCT) can obtain high resolution cross-sectional and volumetric data of lung tissue using rodent models. Access to the lung tissue is obtained by preparing a transparent thorax window. In previous studies, OCT imaging was limited by the depth scan rate and three-dimensional information has been obtained by ...

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    10. Four-dimensional imaging of murine subpleural alveoli using high-speed optical coherence tomography

      Four-dimensional imaging of murine subpleural alveoli using high-speed optical coherence tomography

      The investigation of lung dynamics on alveolar scale is crucial for the understanding and treatment of lung diseases, such as acute lung injury and ventilator induced lung injury, and to promote the development of protective ventilation strategies. One approach to this is the establishment of numerical simulations of lung tissue mechanics where detailed knowledge about three-dimensional alveolar structure changes during the ventilation cycle is required. We suggest four-dimensional optical coherence tomography (OCT) imaging as a promising modality for visualizing the structural dynamics of single alveoli in subpleural lung tissue with high temporal resolution using a mouse model. A high-speed OCT ...

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    11. Multimodal imaging of lung tissue using optical coherence tomography and two photon microscopy

      Multimodal imaging of lung tissue using optical coherence tomography and two photon microscopy

      In the context of protective artificial ventilation strategies for patients with severe lung diseases, the contribution of ventilator settings to tissue changes on the alveolar level of the lung is still a question under debate. To understand the impact of respiratory settings as well as the dynamic process of respiration, high-resolution monitoring and visualization of the dynamics of lung alveoli are essential. An instrument allowing 3D imaging of lung tissue as well as imaging of functional constituents, such as elastin fibers, in in situ experimental conditions is presented in this study using a combination of Fourier domain optical coherence tomography ...

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    12. Quantitative investigation of alveolar structures with OCT using total liquid ventilation during mechanical ventilation

      Quantitative investigation of alveolar structures with OCT using total liquid ventilation during mechanical ventilation

      To develop new treatment possibilities for patients with severe lung diseases it is crucial to understand the lung function on an alveolar level. Optical coherence tomography (OCT) in combination with intravital microscopy (IVM) are used for imaging subpleural alveoli in animal models to gain information about dynamic and morphological changes of lung tissue during mechanical ventilation. The image content suitable for further analysis is influenced by image artifacts caused by scattering, refraction, reflection, and absorbance. Because the refractive index varies with each air-tissue interface in lung tissue, these effects decrease OCT image quality exceedingly. The quality of OCT images can ...

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    13. Investigation of alveolar tissue deformations using OCT combined with fluorescence microscopy

      Investigation of alveolar tissue deformations using OCT combined with fluorescence microscopy

      In critical care medicine, artificial ventilation is a life saving tool providing sufficient blood oxygenation to patients suffering from respiratory failure. Essential for their survival is the use of protective ventilation strategies to prevent further lung damage due to ventilator induced lung injury (VILI). Since there is only little known about implications of lung tissue overdistension on the alveolar level, especially in the case of diseased lungs, this research deals with the investigation of lung tissue deformation on a microscale. A combined setup utilizing optical coherence tomography (OCT) and confocal fluorescence microscopy, is used to study the elastic behavior of ...

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    14. Axial resolution improvement by spectral data fusion in simultaneous dual-band optical coherence tomography

      Axial resolution improvement by spectral data fusion in simultaneous dual-band optical coherence tomography

      A method for axial resolution improvement by adequate spectral data fusion of two parallel acquired disjunct wavelength bands in the 0.8 μm and 1.3 μm region in the field of simultaneous dual-band optical coherence tomography (OCT) is presented. The applied spectral domain dual-band OCT system is illuminated by a supercontinuum laser light source and allows simultaneous imaging at 800 nm and 1250 nm with free-space axial resolutions better than 4.5 μm and 7 μm, respectively, over the entire depth scan range. Each wavelength band is analyzed with an individual spectrometer at an A-scan rate of 12 kHz ...

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    15. Optical coherence tomography for imaging of subpleural alveolar structure using a Fourier domain mode locked laser

      Optical coherence tomography for imaging of subpleural alveolar structure using a Fourier domain mode locked laser

      Optical coherence tomography (OCT) is a noninvasive imaging modality generating cross sectional and volumetric images of translucent samples. In Fourier domain OCT (FD OCT), the depth profile is calculated by a fast Fourier transformation of the interference spectrum, providing speed and SNR advantage and thus making FD OCT well suitable in biomedical applications. The interference spectrum can be acquired spectrally resolved in spectral domain OCT or time-resolved in optical frequency domain imaging (OFDI). Since OCT images still suffer from motion artifacts, especially under in vivo conditions, increased depth scan rates are required. Therefor, the principle of Fourier domain mode locking ...

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    16. Optical coherence tomography in biomedical research

      Optical coherence tomography in biomedical research
      Optical coherence tomography (OCT) is a noninvasive, high-resolution, interferometric imaging modality using near-infrared light to acquire cross-sections and three-dimensional images of the subsurface microstructure of biological specimens. Because of rapid improvement of the acquisition speed and axial resolution of OCT over recent years, OCT is becoming increasingly attractive for applications in biomedical research. Therefore, OCT is no longer used solely for structural investigations of biological samples but also for functional examination, making it potentially useful in bioanalytical science. The combination of in vivo structural and functional findings makes it possible to obtain thorough knowledge on basic physiological and pathological processes ...
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    17. Three-dimensional functional imaging of lung parenchyma using optical coherence tomography combined with confocal fluorescence microscopy

      Three-dimensional functional imaging of lung parenchyma using optical coherence tomography combined with confocal fluorescence microscopy

      Optical coherence tomography (OCT), as a non-invasive technique for studying tissue morphology, is widely used in in vivo studies, requiring high resolution and fast three-dimensional imaging. Based on light scattering it reveals micrometer sized substructures of the samples due to changes in their optical properties and therefore allows quantification of the specimen's geometry. Utilizing fluorescence microscopy further information can be obtained from molecular compositions embedded in the investigated object. Fluorescent markers, specifically binding to the substance of interest, reveal the sample's chemical structure and give rise to functional studies. This research presents the application of a combined OCT ...

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    18. Combining optical coherence tomography with fluorescence microscopy: a closer look into tissue

      Combining optical coherence tomography with fluorescence microscopy: a closer look into tissue

      Optical coherence tomography (OCT) is a technique, capable of high resolution and non-invasive 3D imaging in vivo by detection of backscattered light from cellular and sub cellular structures. Due to visualization of micrometer sized tissue constituents and high penetration depths of up to 2 mm, it is already well established in medical fields like ophthalmology and dermatology. Laser scanning confocal microscopy (LSCM), on the contrary, gives further information on structural tissue components stained with suitable dyes. In combination, these two methods yield three dimensional and high resolution data providing geometrical and structural details of tissue. In this study, we present ...

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    1-20 of 20
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  2. Topics in the News

    1. (20 articles) Dresden University of Technology
    2. (20 articles) Maria Gaertner
    3. (20 articles) Edmund Koch
    4. (12 articles) Sven Meissner
    5. (12 articles) Peter Cimalla
    6. (6 articles) Lars Kirsten
    7. (5 articles) Julia Walther
    8. (3 articles) University of Toronto
    9. (1 articles) Academic Medical Center at the University of Amsterdam
    10. (1 articles) Jichi Medical University
    11. (1 articles) University of Milan
    12. (1 articles) Bern University Hospital
    13. (1 articles) Capital Medical University
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    15. (1 articles) Martin S. Zinkernagel
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    Combining optical coherence tomography with fluorescence microscopy: a closer look into tissue Three-dimensional functional imaging of lung parenchyma using optical coherence tomography combined with confocal fluorescence microscopy Optical coherence tomography in biomedical research Axial resolution improvement by spectral data fusion in simultaneous dual-band optical coherence tomography Investigation of alveolar tissue deformations using OCT combined with fluorescence microscopy Multimodal imaging of lung tissue using optical coherence tomography and two photon microscopy Quantitative investigation of alveolar structures with OCT using total liquid ventilation during mechanical ventilation Four-dimensional imaging of murine subpleural alveoli using high-speed optical coherence tomography Feature Of The Week 5/20/12: Dresden University of Technology Investigates Precision Lung Dynamics Using Four-Dimensional OCT Three-dimensional simultaneous optical coherence tomography and confocal fluorescence microscopy for investigation of lung tissue Correlation between optical coherence tomography, multifocal electroretinogram findings and visual acuity in diabetic macular edema Ciliary body length revisited by anterior segment optical coherence tomography: implications for safe access to the pars plana for intravitreal injections