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Introduction
Publications
Publications (140)
Significance:
Pancreatic surgery is a highly demanding and routinely applied procedure for the treatment of several pancreatic lesions. The outcome of patients with malignant entities crucially depends on the margin resection status of the tumor. Frozen section analysis for intraoperative evaluation of tissue is still time consuming and laborious....
Corneal cross-linking (CXL) with riboflavin and ultraviolet A light is a therapeutic procedure to restore the mechanical stability of corneal tissue. The treatment method is applied to pathological tissue, such as keratoconus and induces the formation of new cross-links. At present, the molecular mechanisms of induced cross-linking are still not kno...
Purpose
Infrared (IR) spectroscopy has the potential for tumor delineation in neurosurgery. Previous research showed that IR spectra of brain tumors are generally characterized by reduced lipid-related and increased protein-related bands. Therefore, we propose the exploitation of these common spectral changes for brain tumor recognition.
Methods
A...
The in ovo sexing of chicken eggs is a current task and a prerequisite to overcome the mass killing of male day-old chicks from laying lines. Although various methods have been developed and tested in recent years, practicable methods for sex determination are still missing which can be applicated in poultry hatcheries before the chicken embryo is...
The determination of exact tumor boundaries within eloquent brain regions is essential to maximize the extent of resection. Recent studies showed that intraoperative optical imaging (IOI) combined with median nerve stimulation is a helpful tool for visualization of the primary sensory cortex (PSC). In this technical note, we describe a novel approa...
Purpose
Infrared (IR) spectroscopy has the potential for tumor delineation in neurosurgery. Previous research showed that IR spectra of brain tumors are generally characterized by reduced lipid-related and increased protein-related bands. Therefore, we propose the exploitation of these common spectral changes for brain tumor recognition.
Methods
A...
COVER ILLUSTRATION Seeing the invisible – Intraoperative Optical Imaging (IOI) is a technique that gives us unique insights on the human brain and it's function. The method uses subtle changes in the optical properties of the exposed cortical brain tissue to detect and visualize hemodynamic changes which are connected to specific brain functions. S...
Alterations within cerebral hemodynamics are the intrinsic signal source for a wide variety of neuroimaging techniques. Stimulation of specific functions leads due to neurovascular coupling, to changes in regional cerebral blood flow, oxygenation and volume. In this study, we investigated the temporal characteristics of cortical hemodynamic respons...
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
We present the infrared spectroscopy study of three types of human healthy and cancerous tissues using standard ATR and fiber optics based ATR techniques. The use of fiber based ATR probes eliminates the need to bring the sample under the study to the spectroscopic instrument and opens the path for the application of infrared spectroscopy for the s...
More than 90% of solid kidney tumors are cancerous and have to be treated by surgical resection where surgical outcomes and patient prognosis are dependent on the tumor discrimination. The development of alternative approaches based on a new generation of fiber attenuated total reflection (ATR) probes could aid tumor identification even under intra...
Background
Label-free multiphoton microscopy has been suggested for intraoperative recognition and delineation of brain tumors. For any future clinical application, appropriate approaches for image acquisition and analysis have to be developed. Moreover, an evaluation of the reliability of the approach, taking into account inter- and intrapatient v...
Intraoperative optical imaging (IOI) is a marker-free, contactless, and noninvasive imaging technique that is able to visualize metabolic changes of the brain surface following neuronal activation. Although it has been used in the past mainly for the identification of functional brain areas under general anesthesia, the authors investigated the pot...
In brain surgery, novel technologies are continuously developed to achieve better tumor delineation and maximize the extent of resection. Raman spectroscopy is an optical method that enables to retrieve a molecular signature of tissue biochemical composition in order to identify tumor and normal tissue. Here, the translation of Raman spectroscopy t...
Human peripheral nerves hold the potential to regenerate after injuries; however, whether a successful axonal regrowth was achieved can be elucidated only months after injury by assessing function. The axolotl salamander is a regenerative model where nerves always regenerate quickly and fully after all types of injury. Here, de- and regeneration of...
Nonlinear multimodal microscopy offers a series of label‐free techniques with potential for intraoperative identification of tumor borders in situ using novel endoscopic devices. Here, we combined coherent anti‐Stokes Raman scattering (CARS), two‐photon excited fluorescence (TPEF) and second harmonic generation (SHG) imaging to analyze biopsies of...
The resection of brain tumor requires a precise distinction between eloquent areas of the brain and pathological tumor tissue in order to improve the extent of resection as well as the patient’s progression free survival time. In this study, we discuss mathematical tools necessary to recognize neural activity using thermal imaging cameras. The main...
Corneal collagen cross-linking (CXL) with riboflavin and UVA light is a therapeutic procedure to restore the mechanical stability of corneal tissue. The treatment method applies to pathological tissue changes, such as keratoconus. It induces the photochemical formation of new collagen cross-links. Although therapeutic effects are indisputable, the...
The success of aneurysm surgery depends on complete clipping of the aneurysmal sacculation without compromising quality of cerebral perfusion of vessels concerned. An established intraoperative method to visualize cerebral blood flow i n a pparent v essels i s fl uorescence vi deo angiography based on indocyanine green (ICG). However, major disadva...
Im Rahmen von neurochirurgischen Interventionen existiert eine Reihe von klinisch
relevanten Fragestellungen, die sich mit Hilfe von modernen bildgebenden Verfahren beantworten lassen. Zu diesen Verfahren zählen u. a. die Intraoperative Optische Bildgebung sowie die thermografische Bildgebung. Um das Outcome für den Patienten zu verbessern, bietet...
Introduction:
Mutations in the isocytrate dehydrogenase 1 (IDH1) gene are early genetic events in glioma pathogenesis and cause profound metabolic changes. Because this genotype is found in virtually every tumor cell, therapies targeting mutant IDH1 protein are being developed. The intraoperative administration of those therapies would require fas...
The development of therapies promoting recovery after spinal cord injury is a challenge. Alginate hydrogels offer the possibility to develop biocompatible implants with mechanical properties tailored to the nervous tissue, which could provide a permissive environment for tissue repair. Here, the effects of non-functionalized soft calcium alginate h...
Octopus and cephalopods are able to regenerate injured tissues. Recent advancements in the study of regeneration in cephalopods appear promising encompassing different approaches helping to decipher cellular and molecular machinery involved in the process. However, lack of specific markers to investigate degenerative/regenerative phenomena and infl...
Label-free multiphoton imaging constitutes a promising technique for clinical diagnosis and therapeutic monitoring. Corpora amylacea (CoA) are starch-like structures often found in the diseased brain, whose origin and role in nervous pathologies are still a matter of debate. Recently, CoA in the diseased human hippocampus were found to be second ha...
In order to provide an alternative to day-old chick culling in the layer hatcheries, a noninvasive method for egg sexing is required at an early stage of incubation before onset of embryo sensitivity. Fluorescence and Raman spectroscopy of blood offers the potential for precise and contactless in ovo sex determination of the domestic chicken (Gallu...
Scores of principal component analysis (female eggs n = 91, male eggs n = 68), used to produce Fig 4B and 4C.
(PDF)
Fluorescence intensity of female eggs (n = 91) and of male eggs (n = 68), used to produce Fig 2B.
(PDF)
Herein, a technique to analyze air-dried kidney tissue impression smears by means of Attenuated Total Reflection Infrared (ATR-IR) spectroscopy is presented. Spectral tumor markers - absorption bands of glycogen - are identified in the ATR-IR spectra of the kidney tissue smear samples. Thin kidney tissue cryo-sections currently used for IR spectros...
The negative correlation between fattening and laying performance prevents breeding improvement in both laying performance and meat yield. Therefore, specialized chicken lines have been bred in order to achieve either an efficient production of high-quality eggs or high growth rates. As a result, day-old male chicks are culled in the layer hatchery...
Purpose:
Somatic mutations in human cytosolic isocitrate dehydrogenase 1 (IDH1) gene cause profound changes in cell metabolism and are a common feature of gliomas with unprecedented predictive and prognostic impact. Fourier-transform infrared (FT-IR) spectroscopy addresses the molecular composition of cells and tissue and was investigated to deduc...
OBJECTIVE
Raman spectroscopy (RS)reveals the molecular composition of tissues and proved to be suitable for intraoperative in situ diagnosis of glioma, including IDH1 genotype. We aimed to investigate fresh tissue biopsies to approximate the the potential and limitations of intraoperative Raman spectroscopy.
METHODS
208 biopsies were obtained duri...
Polycarbonate can be functionalized with specific moieties such as amino groups. A novel approach for functionalization is based on a process integrated surface modification, e.g. during the injection molding process. However, the solid-state reaction routes are complex, not well investigated and difficult to control. In this study the solid state...
Online recognition of cortical blood flow by time-resolved thermography in neurosurgery
We resume the research for contactless in ovo sex determination of the domestic chicken, which has the final aim to provide an alternative to day-old cockerels culling in the layer industry. In ovo Raman and fluorescence spectroscopy of blood of eggs incubated until day 3.5 enables correct sexing rates over 90% barely affecting the hatching rate. F...
Surface enhanced Raman scattering (SERS) spectroscopy is a useful method for detection of trace amounts of molecules. It has already been successfully implemented for detection of explosives, food additives, biomarkers in blood or urine, etc. In the last decade, SERS spectroscopy was introduced into the field of health sciences and has been especia...
Multimodal medical image fusion combines information of one or more images in order to improve the diagnostic value. While previous applications mainly focus on merging images from computed tomography, magnetic resonance imaging (MRI), ultrasonic and single-photon emission computed tomography, we propose a novel approach for the registration and fu...
The properties and structure of tissue can be visualized without labeling or preparation by multiphoton microscopy combining coherent anti-Stokes Raman scattering (CARS), addressing lipid content, second harmonic generation (SHG) showing collagen, and two-photon excited fluorescence (TPEF) of endogenous fluorophores. We compared samples of scleroti...
Culling of day-old male chicks in production of laying hen strains involves several millions of animals every year worldwide and is ethically controversial. In an attempt to provide an alternative, optical spectroscopy was investigated to determine nondestructively in ovo the sex of early embryos of the domestic chicken. The extraembryonic blood ci...
Thermal imaging is a non-invasive and marker-free approach for intraoperative measurements of small temperature variations. In this work, we demonstrate the abilities of active dynamic thermal imaging for analysis of tissue perfusion state in case of cerebral ischemia. For this purpose, a NaCl irrigation is applied to the exposed cortex dur- ing he...
Intraoperative thermal neuroimaging is a novel intraoperative imaging technique for the characterization of perfusion disorders, neural activity and other patho- logical changes of the brain. It bases on the correla- tion of (sub-)cortical metabolism and perfusion with the emitted heat of the cortical surface. In order to min- imize required comput...
Multimodal imaging allows the analysis of orthogonal aspects of imaged subjects. Combining these aspects into a single view might unveil hidden correlations that support more detailed medical decisions. In neurosurgery, preoperative MRI and CT are used to gain knowledge about tissue structure. Functional MRI and intraoperative thermography allow to...
Thermal imaging is a non-invasive and marker-free approach for intraoperative measurements of small temperature variations. In this work, we demonstrate the abilities of active dynamic thermal imaging for analysis of tissue perfusion state in case of cerebral ischemia. For this purpose, a NaCl rinsing is ap- plied to the exposed cortex during hemic...
Male birds of egg-laying hen strains have no commercial value and are culled immediately after hatching, rising concerns for animal welfare. Existing experimental methods for in ovo sexing require taking samples and are applicable after embryos' sexual differentiation. We demonstrate that Raman spectroscopy enables contactless in ovo sex determinat...
Tracing aetiology and pathogenesis of urinary stone disease is of great importance in order to prescribe appropriate treatment and prevent recurrences. For this purpose, morphological examination combined with determination of chemical composition of urinary stones is fundamental. In this work, we have evaluated the potential of multimodal nonlinea...
Spinal cord injury (SCI) triggers several lipid alterations in nervous tissue. It is characterized by extensive demyelination and the inflammatory response leads to accumulation of activated microglia/macrophages, which often transform into foam cells by accumulation of lipid droplets after engulfment of the damaged myelin sheaths. Using an experim...
Thermal induced solid phase polymer reactions between bisphenol-A-based polycarbonate (PC) and polyvinylamine (PVAm) are used to form permanent composite material. The PC-PVAm interface is characterized by infrared (IR) spectroscopy. IR spectra of synthesized reference substances which can be expected after PC-PVAm reaction are recorded and used to...
Determination of cancerous and normal kidney tissues during partial, simple or radical nephrectomy surgery was performed by using differences in the IR absorption spectra of extracellular fluid taken from the corresponding tissue areas. The samples were prepared by stamping of the kidney tissue on ATR diamond crystal. The spectral measurements were...
Coherent anti‐Stokes Raman scattering (CARS) microscopy is an emerging technique for identification of brain tumors. However, tumor identification by CARS microscopy on bulk samples and in vivo has been so far verified retrospectively on histological sections, which only provide a gross reference for the interpretation of CARS images without matchi...
H&E stained sections of SCI in rat models with and without alginate hydrogel implant at one and six months after injury.
(JPG)
Analysis of the contralateral nervous tissue.
IR spectroscopic images of SCI in rat models with and without alginate hydrogel implant at one and six months after injury, obtained plotting the intensity of the lipid-related band at 1735 cm-1.
(JPG)
Analysis of the fibrotic lesion.
IR spectroscopic images of SCI in rat models with and without alginate hydrogel implant at one and six months after injury, obtained plotting the intensity of the collagen-related band at 1242 cm-1.
(JPG)
Spinal cord injury (SCI) induces complex biochemical changes, which result in inhibition of nervous tissue regeneration abilities. In this study, Fourier-transform infrared (FT-IR) spectroscopy was applied to assess the outcomes of implants made of a novel type of non-functionalized soft calcium alginate hydrogel in a rat model of spinal cord hemis...
Activation of CNS resident microglia and invasion of external macrophages plays a central role in spinal cord injuries and diseases. Multiphoton microscopy based on intrinsic tissue properties offers the possibility of label-free imaging and has the potential to be applied in vivo. In this work, we analyzed cellular structures displaying endogenous...
The treatment of spinal cord injury by use of implants that provide a permissive environment for neuron growth is in the focus of the research for regenerative therapies. The effects of alginate hydrogels implants in rat models of surgically-induced spinal cord injury were investigated at different time-points by using Raman-based, label-
free tech...
The treatment of spinal cord injury by using implants that provide a permissive environment for axonal growth is in the focus of the research for regenerative therapies. Here, Raman-based label-free techniques were applied for the characterization of morphochemical properties of surgically induced spinal cord injury in the rat that received an impl...
In this paper, the correction of motion-induced high frequency artifacts on sequences of thermographic images by a real-time capable approach based on Cellular Nonlinear Networks (CNN) is evaluated. For comparison, an offline analysis of frequency subspaces is presented and results will be compared. Both simulated data sets as well as data sets rec...
Mutations in human cytosolic isocitrate dehydrogenases 1 (IDH1) are a common feature of low grade gliomas (LGG) and cause profound changes of the metabolites of the Krebs cycle. Vibrational spectroscopy comprises label-free techniques that probe a sample’s molecular composition. Therefore, we investigated the ability of fourier-transform infrared (...
Changes in tissue composition caused by brain tumor growth involve a series of complex biochemical alterations which can be imaged on unstained native tissue using multiphoton microscopy: We used coherent anti-Stokes Raman scattering (CARS) imaging that resonantly excites the symmetric stretching vibration of CH2 groups at 2850 cm−1 and visualizes...
Multiphoton imaging has evolved as an indispensable tool in cell biology and holds prospects for clinical applications. When addressing endogenous signals such as coherent anti-Stokes Raman scattering (CARS) or second harmonic generation, it requires intense laser irradiation that may cause photodamage. We report that increasing endogenous fluoresc...
Intraoperative thermography allows fast capturing of small temperature variations during neurosurgical operations. External influences induce periodic vibrational motion to the whole camera system superimposing signals of high-frequent neuronal activity, heart rate activity and injected perfusion tracers by motion artifacts. In this work, we propos...
Background
Coherent anti-Stokes Raman scattering (CARS) microscopy provides fine resolution imaging and displays morphochemical properties of unstained tissue. Here, we evaluated this technique to delineate and identify brain tumors.
Methods
Different human tumors (glioblastoma, brain metastases of melanoma and breast cancer) were induced in an or...
Fourier transform infrared (FT-IR) spectroscopy was applied to characterize the extracellular matrix (ECM) of kidney tumor tissue and normal kidney tissue. Freshly resected tissue samples from 31 patients were pressed on a CaF2 substrate. FT-IR spectra obtained from ECM of tumor tissue exhibit stronger absorption bands in the spectral region from 1...
Coherent anti-Stokes Raman scattering (CARS) microscopy is an emerging multiphoton technique for the label-free histopathology of the central nervous system, by imaging the lipid content within the tissue. In order to apply the technique on standard histology sections, it is important to know the effects of tissue fixation on the CARS image. Here,...
Mid-Infrared (MIR) Spectroscopy Near Infrared Spectroscopy Raman Spectroscopy UV/vis Spectroscopy Fluorescence Spectroscopy References
During the past decade, thermographic cameras with high thermal and temporal resolution of up to 30 mK and 50 Hz,
respectively, have been developed. These camera systems can be used to reveal thermal variations and heterogeneities of
tissue and blood. Thus, they provide a fast, sensitive, noninvasive, and label-free application to investigate blood...
Purpose:
Vibrational spectroscopy enables the label-free characterization of cells and tissue by probing the biochemical composition. Here, we evaluated these techniques to identify glioblastoma stem cells.
Materials and methods:
The biochemical fingerprints of glioblastoma cells were established in human cell lines with high and low content of...
In this work the infrared absorption spectra of intercellular fluid of normal and tumor kidney tissue were recorded and analyzed. The samples were prepared by stamping freshly resected tissue onto a CaF2 substrate. FT-IR spectra obtained from intracellular fluid of tumor tissue exhibit stronger absorption bands in the spectral region from 1000-1200...
The unregulated cancer cell growth leads to strong alterations in morphology and composition of the tissue. The combination of coherent anti-Stokes Raman scattering, two-photon excited fluorescence and second harmonic generation enables a high resolution imaging with strong information on tissue composition and can then provide useful information f...