1. Articles from Christian Schnabel

    1-21 of 21
    1. In Vivo Endoscopic Optical Coherence Tomography of the Healthy Human Oral Mucosa: Qualitative and Quantitative Image Analysis

      In Vivo Endoscopic Optical Coherence Tomography of the Healthy Human Oral Mucosa: Qualitative and Quantitative Image Analysis

      To date, there is still a lack of reliable imaging modalities to improve the quality of consultation, diagnostic and medical examinations of the oral mucosa in dentistry. Even though, optical technologies have become an important element for the detection and treatment of different diseases of soft tissue, for the case of oral screenings the evidence of the benefit in comparison to conventional histopathology is mostly still pending. One promising optical technology for oral diagnostics is optical coherence tomography (OCT). To prove the potential of OCT, even the amount of freely accessible OCT data is not sufficient to describe the variance ...

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    2. Optical Coherence Tomography for NDE (Book Chapter)

      Optical Coherence Tomography for NDE (Book Chapter)

      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 samples. Because of the rapid enhancement of OCT with respect to acquisition speed and axial resolution over the past years, OCT is becoming more and more attractive for applications in nondestructive testing and evaluation. In this chapter, a brief introduction to the technique and the instrumentation is first given, followed by an overview of application of OCT in NDE reported so far.

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    3. Multimodal imaging of lung tissue dynamics in mechanically ventilated rats with optical coherence tomography and intravital microscopy

      Multimodal imaging of lung tissue dynamics in mechanically ventilated rats with optical coherence tomography and intravital microscopy

      The understanding of alveolar mechanics is an essential step towards new and more protective ventilation strategies which are of dare need for the treatment of diseases of lung tissue and the airways. Such ailments become a major task for medical care and health care systems in modern industrial countries in the future. Besides the obvious importance as life-saving intervention, the mechanical strain and processes on the level of gas exchange are still insufficiently understood. Therefore, it is of great interest to characterize lung tissue and tissue dynamics during artificial ventilation at the alveolar level. 4D Optical coherence tomography (OCT) in ...

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    4. 4D optical coherence tomography for imaging aortic valve dynamics ex vivo

      4D optical coherence tomography for imaging aortic valve dynamics ex vivo

      The mechanical components of the heart, especially the valves, are enormously stressed during lifetime and undergo different pathophysiological tissue transformations, which affect cardiac output and in consequence living comfort of affected patients. Calcific aortic valve stenosis (AVS) is the most common valve disease in modern industrial countries but the pathogenesis and progression of this disease is still unknown. Therefore, animal models, especially mouse models, are a powerfull tool to investigate this disease in more detail with high resolution imaging techniques like optical coherence tomography and video microscopy. A custom-made pump was used for artificial stimulation of aortic valves ex vivo ...

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    5. In vivo imaging in the oral cavity by endoscopic optical coherence tomography

      In vivo imaging in the oral cavity by endoscopic optical coherence tomography

      The common way to diagnose hard and soft tissue irregularities in the oral cavity is initially the visual inspection by an experienced dentist followed by further medical examinations, such as radiological imaging and/or histopathological investigation. For the diagnosis of oral hard and soft tissues, the detection of early transformations is mostly hampered by poor visual access, low specificity of the diagnosis techniques, and/or limited feasibility of frequent screenings. Therefore, optical noninvasive diagnosis of oral tissue is promising to improve the accuracy of oral screening. Considering this demand, a rigid handheld endoscopic scanner was developed for optical coherence tomography ...

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    6. Advanced analysis of domain walls in Mg doped LiNbO3 crystals with high resolution OCT

      Advanced analysis of domain walls in Mg doped LiNbO3 crystals with high resolution OCT

      The structure of domain walls (DW) in ferroelectric media is of great interest as this material is used for frequency doublers and other applications. We show that the structure of the DWs can nicely be visualized by high resolution optical coherence tomography (OCT). While the high group refractive index of lithium niobate allows a resolution much better than 1 µm, the large dispersion can blur the image and has to be compensated. Therefore, we developed an adaptive dispersion compensation algorithm based on maximizing the intensity of the DWs. By measuring a group of DWs, the mean period of the DWs ...

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    7. 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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    8. Imaging of aortic valve dynamics in 4D OCT New insights into murine aortic valve diseases

      Imaging of aortic valve dynamics in 4D OCT  New insights into murine aortic valve diseases

      The mechanical components of the heart, especially the valves and leaflets, are enormous stressed during lifetime. Therefore, those structures undergo different pathophysiological tissue transformations which affect cardiac output and in consequence living comfort of affected patients. These changes may lead to calcific aortic valve stenosis (AVS), the major heart valve disease in humans. The knowledge about changes of the dynamic behaviour during the course of this disease and the possibility of early stage diagnosis is of particular interest and could lead to the development of new treatment strategies and drug based options of prevention or therapy. 4D optical coherence tomography ...

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    9. 4D optical coherence tomography of aortic valve dynamics in a murine mouse model ex vivo

      4D optical coherence tomography of aortic valve dynamics in a murine mouse model ex vivo

      The heart and its mechanical components, especially the heart valves and leaflets, are under enormous strain during lifetime. Like all highly stressed materials, also these biological components undergo fatigue and signs of wear, which impinge upon cardiac output and in the end on health and living comfort of affected patients. Thereby pathophysiological changes of the aortic valve leading to calcific aortic valve stenosis (AVS) as most frequent heart valve disease in humans are of particular interest. The knowledge about changes of the dynamic behavior during the course of this disease and the possibility of early stage diagnosis could lead to ...

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    10. Ex vivo 4D visualization of aortic valve dynamics in a murine model with optical coherence tomography

      Ex vivo 4D visualization of aortic valve dynamics in a murine model with optical coherence tomography

      The heart and its mechanical components, especially the heart valves and leaflets, are under enormous strain and undergo fatigue, which impinge upon cardiac output. The knowledge about changes of the dynamic behavior and the possibility of early stage diagnosis could lead to the development of new treatment strategies. Animal models are suited for the development and evaluation of new experimental approaches and therefor innovative imaging techniques are necessary. In this study, we present the time resolved visualization of healthy and calcified aortic valves in an ex vivo artificially stimulated heart model with 4D optical coherence tomography and high-speed video microscopy.

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    11. 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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    12. 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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    13. 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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    14. 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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    15. 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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    16. 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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    17. 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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    18. Improved OCT imaging of lung tissue using a prototype for total liquid ventilation

      Improved OCT imaging of lung tissue using a prototype for total liquid ventilation
      Optical coherence tomography (OCT) is used for imaging subpleural alveoli in animal models to gain information about dynamic and morphological changes of lung tissue during mechanical ventilation. The quality of OCT images can be increased if the refraction index inside the alveoli is matched to the one of tissue via liquid-filling. Thereby, scattering loss can be decreased and higher penetration depth and tissue contrast can be achieved. Until now, images of liquid-filled lungs were acquired in isolated and fixated lungs only, so that an in vivo measurement situation is not present. To use the advantages of liquid-filling for in vivo ...
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    19. Three-dimensional Fourier domain optical coherence tomography in vivo imaging of alveolar tissue in the intact thorax using the parietal pleura as a window

      Three-dimensional Fourier domain optical coherence tomography in vivo imaging of alveolar tissue in the intact thorax using the parietal pleura as a window
      In vivo determination of 3-D and dynamic geometries of alveolar structures with adequate resolution is essential for developing numerical models of the lung. A thorax window is prepared in anesthetized rabbits by removal of muscle tissue between the third and fourth rib without harming the parietal pleura. The transparent parietal pleura allows contact-free imaging by intravital microscopy IVM and 3-D optical coherence tomography 3-D OCT. We demonstrate that dislocation of the lung surface is small enough to observe identical regions in the expiratory and inspiratory plateau phase, and that OCT in this animal model is suitable for generating 3-D geometry ...
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    1-21 of 21
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    1. (21 articles) Dresden University of Technology
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    Three-dimensional Fourier domain optical coherence tomography in vivo imaging of alveolar tissue in the intact thorax using the parietal pleura as a window Improved OCT imaging of lung tissue using a prototype for total liquid ventilation 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 Four-dimensional optical coherence tomography imaging of total liquid ventilated rats 3D Optical Coherence Tomography for Investigating Alveolar Structures During Total Liquid Ventilation Ex vivo 4D visualization of aortic valve dynamics in a murine model with optical coherence tomography Factors Associated with Changes in Retinal Layers Following Acute Optic Neuritis: A Longitudinal Study Using Optical Coherence Tomography Relationship between N95 Amplitude of Pattern Electroretinogram and Optical Coherence Tomography Angiography in Open-Angle Glaucoma