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Polanski WH, Oelschlägel M, Juratli TA, Wahl H, Krukowski PM, Morgenstern U, Koch E, Steiner G, Schackert G, Sobottka SB. Topographic Mapping of the Primary Sensory Cortex Using Intraoperative Optical Imaging and Tactile Irritation. Brain Topogr 2023; 36:1-9. [PMID: 36446998 PMCID: PMC9834102 DOI: 10.1007/s10548-022-00925-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 10/30/2022] [Indexed: 11/30/2022]
Abstract
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 approach of using IOI with painless tactile irritation to demonstrate the feasibility of topographic mapping of different body regions within the PSC. In addition, we compared the IOI results with preoperative functional MRI (fMRI) findings. In five patients with tumors located near the PSC who received tumor removal, IOI with tactile irritation of different body parts and fMRI was applied. We showed that tactile irritation of the hand in local and general anesthesia leads to reliable changes of cerebral blood volume during IOI. Hereby, we observed comparable IOI activation maps regarding the median nerve stimulation, fMRI and tactile irritation of the hand. The tactile irritation of different body areas revealed a plausible topographic distribution along the PSC. With this approach, IOI is also suitable for awake surgeries, since the tactile irritation is painless compared with median nerve stimulation and is congruent to fMRI findings. Further studies are ongoing to standardize this method to enable a broad application within the neurosurgical community.
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Affiliation(s)
- Witold H. Polanski
- Department of Neurosurgery, University Hospital of Dresden, Fiedlerstr. 74, 01307 Dresden, Germany
| | - Martin Oelschlägel
- Clinical Sensoring and Monitoring, Faculty of Medicine, University Hospital Carl Gustav Carus, Dresden University of Technology, 01307 Dresden, Germany
| | - Tareq A. Juratli
- Department of Neurosurgery, University Hospital of Dresden, Fiedlerstr. 74, 01307 Dresden, Germany
| | - Hannes Wahl
- Institute of Diagnostic and Interventional Neuroradiology, University Hospital Carl Gustav Carus, Technical University of Dresden, Fetscherstr. 74, 01307 Dresden, Germany
| | - Pawel M. Krukowski
- Institute of Diagnostic and Interventional Neuroradiology, University Hospital Carl Gustav Carus, Technical University of Dresden, Fetscherstr. 74, 01307 Dresden, Germany
| | - Ute Morgenstern
- Institute of Biomedical Engineering, Faculty of Electrical and Computer Engineering, Technische Universität Dresden, 01307 Dresden, Germany
| | - Edmund Koch
- Clinical Sensoring and Monitoring, Faculty of Medicine, University Hospital Carl Gustav Carus, Dresden University of Technology, 01307 Dresden, Germany
| | - Gerald Steiner
- Clinical Sensoring and Monitoring, Faculty of Medicine, University Hospital Carl Gustav Carus, Dresden University of Technology, 01307 Dresden, Germany
| | - Gabriele Schackert
- Department of Neurosurgery, University Hospital of Dresden, Fiedlerstr. 74, 01307 Dresden, Germany
| | - Stephan B. Sobottka
- Department of Neurosurgery, University Hospital of Dresden, Fiedlerstr. 74, 01307 Dresden, Germany
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Oelschlägel M, Polanski WH, Morgenstern U, Steiner G, Kirsch M, Koch E, Schackert G, Sobottka SB. Characterization of cortical hemodynamic changes following sensory, visual, and speech activation by intraoperative optical imaging utilizing phase-based evaluation methods. Hum Brain Mapp 2022; 43:598-615. [PMID: 34590384 PMCID: PMC8720199 DOI: 10.1002/hbm.25674] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 09/14/2021] [Indexed: 11/12/2022] Open
Abstract
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 responses following electrical, tactile, visual, and speech activation for different stimulation paradigms using Intraoperative Optical Imaging (IOI). Image datasets from a total of 22 patients that underwent surgical resection of brain tumors were evaluated. The measured reflectance changes at different light wavelength bands, representing alterations in regional cortical blood volume (CBV), and deoxyhemoglobin (HbR) concentration, were assessed by using Fourier-based evaluation methods. We found a decrease of CBV connected to an increase of HbR within the contralateral primary sensory cortex (SI) in patients that were prolonged (30 s/15 s) electrically stimulated. Additionally, we found differences in amplitude as well as localization of activated areas for different stimulation patterns. Contrary to electrical stimulation, prolonged tactile as well as prolonged visual stimulation are provoking increases in CBV within the corresponding activated areas (SI, visual cortex). The processing of the acquired data from awake patients performing speech tasks reveals areas with increased, as well as areas with decreased CBV. The results lead us to the conclusion, that the CBV decreases in connection with HbR increases in SI are associated to processing of nociceptive stimuli and that stimulation type, as well as paradigm have a nonnegligible impact on the temporal characteristics of the following hemodynamic response.
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Affiliation(s)
- Martin Oelschlägel
- Department of Anesthesiology and Intensive Care Medicine, Technische Universität Dresden, Carl Gustav Carus Faculty of Medicine, Clinical Sensoring and Monitoring, Dresden, Saxony, Germany
| | - Witold H Polanski
- Department of Neurosurgery, Technische Universität Dresden, Carl Gustav Carus University Hospital Dresden, Dresden, Saxony, Germany
| | - Ute Morgenstern
- Faculty of Electrical and Computer Engineering, Technische Universität Dresden, Institute of Biomedical Engineering, Dresden, Saxony, Germany
| | - Gerald Steiner
- Department of Anesthesiology and Intensive Care Medicine, Technische Universität Dresden, Carl Gustav Carus Faculty of Medicine, Clinical Sensoring and Monitoring, Dresden, Saxony, Germany
| | - Matthias Kirsch
- Department of Neurosurgery, Technische Universität Dresden, Carl Gustav Carus University Hospital Dresden, Dresden, Saxony, Germany.,Department of Neurosurgery, Asklepios Kliniken Schildautal Seesen, Seesen, Saxony, Germany
| | - Edmund Koch
- Department of Anesthesiology and Intensive Care Medicine, Technische Universität Dresden, Carl Gustav Carus Faculty of Medicine, Clinical Sensoring and Monitoring, Dresden, Saxony, Germany
| | - Gabriele Schackert
- Department of Neurosurgery, Technische Universität Dresden, Carl Gustav Carus University Hospital Dresden, Dresden, Saxony, Germany
| | - Stephan B Sobottka
- Department of Neurosurgery, Technische Universität Dresden, Carl Gustav Carus University Hospital Dresden, Dresden, Saxony, Germany
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Oelschlägel M, Polanski WH, Morgenstern U, Steiner G, Kirsch M, Koch E, Schackert G, Sobottka SB. Cover Image. Hum Brain Mapp 2022. [DOI: 10.1002/hbm.25479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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4
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Frank S, Reglitz K, Mall V, Morgenstern U, Steinhaus M. Molecular background of the undesired odor of polypropylene materials and insights into the sources of key odorants. Indoor Air 2021; 31:1038-1049. [PMID: 33749958 DOI: 10.1111/ina.12821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 02/02/2021] [Accepted: 02/28/2021] [Indexed: 06/12/2023]
Abstract
Screening the volatiles isolated from a standard polypropylene material consisting of a polypropylene homopolymer, the filler talcum, and a mixture of antioxidants, for odor-active compounds by application of an aroma extract dilution analysis revealed 30 odorants with flavor dilution factors ranging from 1 to 64. Eighteen odor-active compounds were subsequently quantitated by gas chromatography-mass spectrometry using stable isotopically substituted odorants as internal standards, and their odor activity values (OAVs) were calculated as ratios of the concentrations to the odor threshold values. Five odorants showed OAVs ≥1, among which were hex-1-en-3-one (OAV 12), butanoic acid (OAV 3), as well as 4-methylphenol, butan-1-ol, and 2-tert-butylphenol (all OAV 1). A comparative analysis of polypropylene materials with different additives suggested plastic-like, pungent smelling hex-1-en-3-one as an ubiquitous key odorant. Odor-active amounts of alkylphenols, in particular plastic-like, phenolic smelling 2-tert-butylphenol, were additionally formed in the presence of talcum and phenolic antioxidants. Whereas the precursors of the phenols were thus obvious, the origin of hex-1-en-3-one was unknown. Injection molding showed only little influence on odorant concentrations.
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Affiliation(s)
- Stephanie Frank
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich (Leibniz-LSB@TUM), Freising, Germany
| | - Klaas Reglitz
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich (Leibniz-LSB@TUM), Freising, Germany
| | - Veronika Mall
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich (Leibniz-LSB@TUM), Freising, Germany
| | - Ute Morgenstern
- Forschungsinstitut für Leder und Kunststoffbahnen (FILK), Freiberg, Germany
| | - Martin Steinhaus
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich (Leibniz-LSB@TUM), Freising, Germany
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Mühle R, Ernst H, Sobottka SB, Morgenstern U. Workflow and hardware for intraoperative hyperspectral data acquisition in neurosurgery. BIOMED ENG-BIOMED TE 2020; 66:/j/bmte.ahead-of-print/bmt-2019-0333/bmt-2019-0333.xml. [PMID: 32706748 DOI: 10.1515/bmt-2019-0333] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 05/27/2020] [Indexed: 01/18/2023]
Abstract
To prevent further brain tumour growth, malignant tissue should be removed as completely as possible in neurosurgical operations. Therefore, differentiation between tumour and brain tissue as well as detecting functional areas is very important. Hyperspectral imaging (HSI) can be used to get spatial information about brain tissue types and characteristics in a quasi-continuous reflection spectrum. In this paper, workflow and some aspects of an adapted hardware system for intraoperative hyperspectral data acquisition in neurosurgery are discussed. By comparing an intraoperative with a laboratory setup, the influences of the surgical microscope are made visible through the differences in illumination and a pixel- and wavelength-specific signal-to-noise ratio (SNR) calculation. Due to the significant differences in shape and wavelength-dependent intensity of light sources, it can be shown which kind of illumination is most suitable for the setups. Spectra between 550 and 1,000 nm are characterized of at least 40 dB SNR in laboratory and 25 dB in intraoperative setup in an area of the image relevant for evaluation. A first validation of the intraoperative hyperspectral imaging hardware setup shows that all system parts and intraoperatively recorded data can be evaluated. Exemplarily, a classification map was generated that allows visualization of measured properties of raw data. The results reveal that it is possible and beneficial to use HSI for wavelength-related intraoperative data acquisition in neurosurgery. There are still technical facts to optimize for raw data detection prior to adapting image processing algorithms to specify tissue quality and function.
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Affiliation(s)
- Richard Mühle
- Faculty of Electrical and Computer Engineering, Institute of Biomedical Engineering, Technische Universität Dresden, 01062Dresden, Germany
- Department of Neurosurgery, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307Dresden, Germany
| | - Hannes Ernst
- Faculty of Electrical and Computer Engineering, Institute of Biomedical Engineering, Technische Universität Dresden, 01062Dresden, Germany
| | - Stephan B Sobottka
- Department of Neurosurgery, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307Dresden, Germany
| | - Ute Morgenstern
- Faculty of Electrical and Computer Engineering, Institute of Biomedical Engineering, Technische Universität Dresden, 01062Dresden, Germany
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Oelschlägel M, Meyer T, Morgenstern U, Wahl H, Gerber J, Reiß G, Koch E, Steiner G, Kirsch M, Schackert G, Sobottka SB. Mapping of language and motor function during awake neurosurgery with intraoperative optical imaging. Neurosurg Focus 2020; 48:E3. [PMID: 32006940 DOI: 10.3171/2019.11.focus19759] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/15/2019] [Indexed: 11/06/2022]
Abstract
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 potential of the method during awake surgery. Measurements were performed in 10 patients who underwent resection of lesions within or adjacent to cortical language or motor sites. IOI was applied in 3 different scenarios: identification of motor areas by using finger-tapping tasks, identification of language areas by using speech tasks (overt and silent speech), and a novel approach-the application of IOI as a feedback tool during direct electrical stimulation (DES) mapping of language. The functional maps, which were calculated from the IOI data (activity maps), were qualitatively compared with the functional MRI (fMRI) and the electrophysiological testing results during the surgical procedure to assess their potential benefit for surgical decision-making.The results reveal that the intraoperative identification of motor sites with IOI in good agreement with the preoperatively acquired fMRI and the intraoperative electrophysiological measurements is possible. Because IOI provides spatially highly resolved maps with minimal additional hardware effort, the application of the technique for motor site identification seems to be beneficial in awake procedures. The identification of language processing sites with IOI was also possible, but in the majority of cases significant differences between fMRI, IOI, and DES were visible, and therefore according to the authors' findings the IOI results are too unspecific to be useful for intraoperative decision-making with respect to exact language localization. For this purpose, DES mapping will remain the method of choice.Nevertheless, the IOI technique can provide additional value during the language mapping procedure with DES. Using a simple difference imaging approach, the authors were able to visualize and calculate the spatial extent of activation for each stimulation. This might enable surgeons in the future to optimize the mapping process. Additionally, differences between tumor and nontumor stimulation sites were observed with respect to the spatial extent of the changes in cortical optical properties. These findings provide further evidence that the method allows the assessment of the functional state of neurovascular coupling and is therefore suited for the delineation of pathologically altered tissue.
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Affiliation(s)
- Martin Oelschlägel
- 1Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden
| | - Tobias Meyer
- 2ABX-CRO Advanced Pharmaceutical Services Forschungsgesellschaft mbH, Dresden
| | - Ute Morgenstern
- 3Institute of Biomedical Engineering, Faculty of Electrical and Computer Engineering, Technische Universität Dresden
| | - Hannes Wahl
- 4Institute and Polyclinic of Diagnostic and Interventional Neuroradiology, Carl Gustav Carus University Hospital, Technische Universität Dresden
| | - Johannes Gerber
- 4Institute and Polyclinic of Diagnostic and Interventional Neuroradiology, Carl Gustav Carus University Hospital, Technische Universität Dresden
| | - Gilfe Reiß
- 6Department of Neurosurgery, Carl Gustav Carus University Hospital, Technische Universität Dresden, Saxony, Germany
| | - Edmund Koch
- 1Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden
| | - Gerald Steiner
- 1Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden
| | - Matthias Kirsch
- 5Department of Neurosurgery, Asklepios Kliniken Schildautal Seesen; and
| | - Gabriele Schackert
- 6Department of Neurosurgery, Carl Gustav Carus University Hospital, Technische Universität Dresden, Saxony, Germany
| | - Stephan B Sobottka
- 6Department of Neurosurgery, Carl Gustav Carus University Hospital, Technische Universität Dresden, Saxony, Germany
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Martindale H, Morgenstern U, Singh R, Stewart B. Optimisation of enrichment methods and evaluation of errors for high sensitivity measurement of 222Rn in natural waters. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06474-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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8
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Clague JC, Stenger R, Morgenstern U. The influence of unsaturated zone drainage status on denitrification and the redox succession in shallow groundwater. Sci Total Environ 2019; 660:1232-1244. [PMID: 30743918 DOI: 10.1016/j.scitotenv.2018.12.383] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/20/2018] [Accepted: 12/24/2018] [Indexed: 06/09/2023]
Abstract
Since nitrate is a major agricultural freshwater contaminant, denitrification is the environmentally most important step in the ecological succession of redox processes that can occur in groundwater. Understanding where and to what extent denitrification occurs would enable spatially differentiated land management and regulation. We investigated in a dairy farming catchment in the North Island of New Zealand the influence of the unsaturated zone's drainage status on the redox succession in shallow groundwater along a well transect spanning drainage conditions from well drained to very poorly drained. Groundwater samples were analysed for a variety of parameters including nitrate, tritium, dinitrogen, argon, methane and nitrous oxide. The redox classification based on measured redox-sensitive parameters broadly matched the a priori assessed drainage status of the overlying unsaturated zone. Only the groundwater underlying the well-drained soil was oxic and reflected the N losses from the intensive pastoral land use, with nitrate nitrogen concentrations up to 9.6 mg L-1. All other sites had mildly to strongly reduced groundwater and concomitantly decreasing or low nitrate concentrations, even at the water table. The tritium-derived mean residence time (MRT) estimates for the oxic groundwater (12 and 14 y) were within the range found in mildly reduced groundwater from the imperfectly drained sites (6-24 y), with the exception of one sample from below an aquitard (105 y). In contrast, the strongly reduced groundwater observed at the poorly and very poorly drained sites was relatively immobile (55 to >110 y). Denitrification was confirmed by the nitrate dual isotope signatures, and by the occurrence of excess dinitrogen, and likely occurred in both the unsaturated and saturated zones. A coherent sampling scheme throughout the unsaturated zone - saturated zone continuum should be used in future studies to allow ascertaining the exact location of denitrification activity in vertical profiles.
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Affiliation(s)
- J C Clague
- Lincoln Agritech Ltd, Private Bag 3062, Hamilton, New Zealand.
| | - R Stenger
- Lincoln Agritech Ltd, Private Bag 3062, Hamilton, New Zealand
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Gusyev MA, Morgenstern U, Nishihara T, Hayashi T, Akata N, Ichiyanagi K, Sugimoto A, Hasegawa A, Stewart MK. Evaluating anthropogenic and environmental tritium effects using precipitation and Hokkaido snowpack at selected coastal locations in Asia. Sci Total Environ 2019; 659:1307-1321. [PMID: 31096342 DOI: 10.1016/j.scitotenv.2018.12.342] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/22/2018] [Accepted: 12/22/2018] [Indexed: 06/09/2023]
Abstract
Tritium dating requires a good understanding of the tritium and water inputs into hydrologic systems, including their main trends due to latitudinal, seasonal and altitudinal effects. Although tritium reached ambient levels at the end of the 20th century, tritium released from nuclear facilities and bomb tests since then has the potential to confound use of tritium for age dating. We therefore collected precipitation and snowpack samples for tritium analysis to confirm that tritium levels in Japanese precipitation had not exceeded ambient levels following the North Korean nuclear tests in January 6th 2016 and September 3rd 2017. As the result, the highest tritium concentration was 5.52(±0.27)TU at samples collected from January 8 to 11th at one Honshu and four Hokkaido locations and samples collected at six Honshu locations had 8.01(±1.5)TU from September 6 to 19th 2017. Confirming ambient tritium concentrations after both events we investigated the latitude tritium effect at selected coastal stations in Asia, indicating a break of latitude trend around Tokyo area, and established the latitude scaling factors to the north and south of the Tokyo area data. The seasonal trend was investigated during the winter-spring 2016 in precipitation samples confirming the higher spring tritium compared with winter continental tritium values. The altitude effect on tritium and stable (18O and 2H) isotopes was observed in Hokkaido snowpack, which had tritium concentrations ranging between 4.08 and 5.93 TU during March-April, and demonstrated two trends for western and central Hokkaido mountain ranges. Using established latitude and altitude scaling factors with the long-term continuous time-series of monthly Tokyo area tritium we estimated the annual weighted tritium at 110 meteorological stations in Japan with monthly precipitation demonstrating the applicability of this approach for future tritium-tracer studies across Asia.
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Affiliation(s)
- M A Gusyev
- International Centre for Water Hazard and Risk Management (ICHARM)/National Graduate Institute for Policy Studies (GRIPS), Public Works Research Institute (PWRI), Tsukuba 305-8516, Japan.
| | | | - T Nishihara
- Civil Engineering Research Institute for Cold Region (CERI), PWRI, Sapporo 062-8602, Japan
| | - T Hayashi
- Akita University, Akita 010-8502, Japan
| | - N Akata
- National Institute for Fusion Science (NIFS), Toki 509-5292, Japan
| | | | - A Sugimoto
- Hokkaido University, Sapporo 060-0808, Japan
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Nahm W, Hornberger C, Morgenstern U, Sobottka SB. Optical imaging methods in medicine: how can we escape the plausibility trap? BIOMED ENG-BIOMED TE 2018; 63:507-510. [PMID: 30243014 DOI: 10.1515/bmt-2018-2001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Werner Nahm
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Christoph Hornberger
- Faculty of Engineering, Wismar University of Applied Sciences, 23966 Wismar, Germany
| | - Ute Morgenstern
- Institute of Biomedical Engineering, Faculty of Electrical and Computer Engineering, Technische Universität Dresden, 01307 Dresden, Germany
| | - Stephan B Sobottka
- Department of Neurosurgery, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
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11
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Stenger R, Clague JC, Morgenstern U, Clough TJ. Vertical stratification of redox conditions, denitrification and recharge in shallow groundwater on a volcanic hillslope containing relict organic matter. Sci Total Environ 2018; 639:1205-1219. [PMID: 29929288 DOI: 10.1016/j.scitotenv.2018.05.122] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/09/2018] [Accepted: 05/09/2018] [Indexed: 06/08/2023]
Abstract
Natural denitrification in groundwater systems has been recognised as an ecosystem service that reduces the impact of agriculturally-derived nitrate inputs to surface waters. Identification of this ecosystem service within the landscape would permit spatially differentiated land management and legislation. However, spatial variation in groundwater redox conditions poses a significant challenge to such a concept. To gain understanding of the small-scale mosaic of biogeochemical and hydrological controls on denitrification, we established a well field consisting of 11 multilevel well (MLW) clusters on a hillslope containing relict organic matter buried by volcanic deposits 1.8 ka before present. Based on site-specific redox classification thresholds, vertical redox gradients and denitrification potentials were detected at 7 of the 11 sites. Palaeosols or woody debris, which had previously been identified in laboratory experiments as resident electron donors fuelling denitrification, were visually recognisable at 4 of the 7 MLW sites with vertical redox gradients. Moderately enhanced groundwater dissolved organic carbon (DOC) concentrations occurred where resident electron donors were evident. DOC concentrations were lower where anoxic and nitrate-depleted groundwater was found but with an absence of resident electron donors. In these instances, it was assumed that nitrate reduction had occurred somewhere upgradient of the sampled well screen along the lateral groundwater flow path, with the proximate electron donor (DOC) largely consumed in the process, since no evidence was found for denitrification being fuelled by inorganic electron donors. Due to high variability in the isotopic signature of nitrate in oxidised groundwater, the nitrate dual isotope method did not yield firm evidence for denitrification. However, realistic vertical patterns were obtained using the excess N2 method. Tritium-based age dating revealed that oxic conditions were restricted to young groundwater (mean residence time ≤ 3 y), while anoxic conditions were observed across a wider age range (3-25 y).
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Affiliation(s)
- R Stenger
- Lincoln Agritech Ltd, Private Bag 3062, Hamilton, New Zealand.
| | - J C Clague
- Lincoln Agritech Ltd, Private Bag 3062, Hamilton, New Zealand.
| | | | - T J Clough
- Department of Soil and Physical Sciences, PO Box 85084, Lincoln University, Lincoln, New Zealand.
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Oelschlägel M, Meyer T, Schackert G, Kirsch M, Sobottka SB, Morgenstern U. Intraoperative optical imaging of metabolic changes after direct cortical stimulation – a clinical tool for guidance during tumor resection? ACTA ACUST UNITED AC 2018; 63:587-594. [DOI: 10.1515/bmt-2017-0156] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 10/24/2017] [Indexed: 11/15/2022]
Abstract
Abstract
Brain tumor resection is even today one of the most challenging disciplines in neurosurgery. The current state of the art for the identification of tumor tissue during the surgical procedure comprises a wide variety of different tools, each with its own limitations and drawbacks. In this paper, we present a novel approach, the use of optical imaging in connection with direct electrical cortical stimulation (DCS), for identification of impaired tumor tissue and functional intact normal brain tissue under intraoperative conditions. Measurements with an optical imaging setup were performed as a proof of concept on three patients who underwent tumor resection of superficial gliomas. Direct electrical stimulations were applied on tumor tissue and surrounding brain tissue in each patient and characteristic features from the observed changes in the optical properties were compared between the different groups. The results reveal that in all patients a differentiation between non-functional tumor tissue and functional intact brain tissue was possible, and the technique might be a useful clinical tool in the future.
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Affiliation(s)
- Martin Oelschlägel
- Faculty of Electrical and Computer Engineering, Technische Universität Dresden , Institut für Biomedizinische Technik , D – 01307 Dresden , Germany , Phone: +49 351 463 32118, Fax: +49 351 463 36026
| | - Tobias Meyer
- Institute of Biomedical Engineering, Faculty of Electrical and Computer Engineering , Technische Universität Dresden , 01307 Dresden , Germany
- ABX-CRO Advanced Pharmaceutical Services Forschungsgesellschaft m.b.H. , 01307 Dresden , Germany
| | - Gabriele Schackert
- Department of Neurosurgery, Faculty of Medicine Carl Gustav Carus , Technische Universität Dresden , 01307 Dresden , Germany
| | - Matthias Kirsch
- Department of Neurosurgery, Faculty of Medicine Carl Gustav Carus , Technische Universität Dresden , 01307 Dresden , Germany
| | - Stephan B. Sobottka
- Department of Neurosurgery, Faculty of Medicine Carl Gustav Carus , Technische Universität Dresden , 01307 Dresden , Germany
| | - Ute Morgenstern
- Institute of Biomedical Engineering, Faculty of Electrical and Computer Engineering , Technische Universität Dresden , 01307 Dresden , Germany
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Morgenstern U, Steinmeier R, Uhlemann F. Objective Evaluation of Three-dimensional Image Registration Algorithms – Tools for Optimization and Evaluation. Methods Inf Med 2018. [DOI: 10.1055/s-0038-1633879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Summary
Objective:
The registration of medical volume data sets plays an important role when different images or modalities are used during computer-assisted surgical procedures. Nevertheless, it is often questionable how robust and accurate the underlying algorithms really are. Therefore, the goal is to foster the establishment of methods for an objective evaluation.
Method:
To reliably calculate the accuracy of registration algorithms, a reference transformation must be known. Due to the unknown perfect registration for real clinical data, the simulation of realistic data and successive affine transformations are employed. The simulation is based on models of the respective imaging modality where the dominant physical effects are taken into account. This gives the user full control over all simulation and transformation parameters. Finally, suitable quality measures are applied which allow a systematic evaluation of image registration accuracy by comparing the known theoretical result and the transformation calculated by the algorithm under investigation.
Results:
During the development of a new registration algorithm, the presented method proved to be a very valuable tool for optimization and evaluation of registration accuracy, since it allows objective numerical comparison of the calculated results.
Conclusions:
The presented method can be used during the development of algorithms for optimization and for quantitative comparison of different registration schemes. The respective software tool can automatically generate and transform simulated but realistic data. Employing suitable numerical quality measures, an objective evaluation of registration results can be easily obtained. Still, the validity of the relatively simple models has to be verified to draw reliable conclusions with respect to real data.
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Owen DDR, Shouakar-Stash O, Morgenstern U, Aravena R. Thermodynamic and hydrochemical controls on CH4 in a coal seam gas and overlying alluvial aquifer: new insights into CH4 origins. Sci Rep 2016; 6:32407. [PMID: 27578542 PMCID: PMC5006171 DOI: 10.1038/srep32407] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 08/03/2016] [Indexed: 11/18/2022] Open
Abstract
Using a comprehensive data set (dissolved CH4, δ13C-CH4, δ2H-CH4, δ13C-DIC, δ37Cl, δ2H-H2O, δ18O-H2O, Na, K, Ca, Mg, HCO3, Cl, Br, SO4, NO3 and DO), in combination with a novel application of isometric log ratios, this study describes hydrochemical and thermodynamic controls on dissolved CH4 from a coal seam gas reservoir and an alluvial aquifer in the Condamine catchment, eastern Surat/north-western Clarence-Moreton basins, Australia. δ13C-CH4 data in the gas reservoir (−58‰ to −49‰) and shallow coal measures underlying the alluvium (−80‰ to −65‰) are distinct. CO2 reduction is the dominant methanogenic pathway in all aquifers, and it is controlled by SO4 concentrations and competition for reactants such as H2. At isolated, brackish sites in the shallow coal measures and alluvium, highly depleted δ2H-CH4 (<310‰) indicate acetoclastic methanogenesis where SO4 concentrations inhibit CO2 reduction. Evidence of CH4 migration from the deep gas reservoir (200–500 m) to the shallow coal measures (<200 m) or the alluvium was not observed. The study demonstrates the importance of understanding CH4 at different depth profiles within and between aquifers. Further research, including culturing studies of microbial consortia, will improve our understanding of the occurrence of CH4 within and between aquifers in these basins.
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Affiliation(s)
- D Des R Owen
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Queensland, 4000, Australia
| | | | - U Morgenstern
- GNS Science, Lower Hutt 5014, P.O. Box 30368, New Zealand
| | - R Aravena
- Department of Earth and Environmental Sciences, University of Waterloo, Ontario N2L 3G1, Canada
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Huhle R, Siegert J, Wonka F, Schindler C, de Abreu MG, Koch T, Morgenstern U, Theilen H. Assessing the eligibility of a non-invasive continuous blood pressure measurement technique for application during total intravenous anaesthesia. ACTA ACUST UNITED AC 2016; 61:369-79. [PMID: 26859497 DOI: 10.1515/bmt-2015-0001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 11/10/2015] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To assess the eligibility for replacement of invasive blood pressure as measured "within" the arterial vessel (IBP) with non-invasive continuous arterial blood pressure (cNIP) monitoring during total intravenous anaesthesia (TIVA), the ability of cNiP to track fast blood pressure changes needs to be quantified. A new method of statistical data analysis is developed for this purpose. METHODS In a pilot study on patients undergoing neurosurgical anaesthesia, mean arterial pressure MAPIBP measured with IBP was compared to MAPCNP measured by the CNAP Monitor 500 in ten patients (age: 63±13 a). Correlation analysis of changes of device differences ΔeMAP=ΔMAPCNP-ΔMAPIBP with changes of MAPIBP (ΔMAPIBP) during intervals of vasoactivity was conducted. An innovative technique, of linear trend analysis (LTA) applied to two signals, is described to perform this analysis without a priori knowledge of intervals of vasoactivity. RESULTS Analysis of ΔeMAP during vasoactivity revealed that ΔMAPCNP systematically underestimated ΔMAPIBP by 37%. This was confirmed in the complete data set using LTA technique showing a systematic, yet patient specific, underestimation in tracking ΔMAPIBP (16…120%). CONCLUSION The proposed LTA technique is able to detect systematic errors in tracking short-term blood pressure changes otherwise masked by established analysis. LTA may thus be a useful tool to assess the eligibility of cNIP to replace IBP during TIVA.
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Oelschlägel M, Meyer T, Sobottka SB, Kirsch M, Schackert G, Morgenstern U. Intraoperative identification of somato-sensory brain areas using optical imaging and standard RGB camera equipment – a feasibility study. Current Directions in Biomedical Engineering 2015. [DOI: 10.1515/cdbme-2015-0066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Intraoperative Optical Imaging (IOI) is a neuro-imaging technique that allows the visualization of changes in optical properties of the brain cortex. Recent developments enhanced the method regarding the robustness under intraoperative conditions. However, the necessity of additional hardware still limits the use in the operating room (OR). Since modern surgical microscopes are potentially equipped with all required hardware for imaging, we investigated the possible use of such standard RGB camera for IOI. Measurements were performed on eight patients. Changes in optical properties of the cortical surface were acquired with a monochrome CCD camera (AxioCam MRm) and simultaneously with a standard RGB camera (Trio 610). Maps of cortical activity were calculated from the image data and the quality of these maps was assessed with a spatial signal-to-noise ratio. Activity maps calculated from AxioCam MRm data showed highest SNR in six out of eight patients. In two patients the activity map calculated from Trio 610 red channel performed best overall. The Trio 610 maps calculated from red channel data performed best in three out of eight cases like the activity maps calculated from green channel data, whereas the activity map calculated from blue channel data performed best in only two cases. If the color channel with the highest SNR is chosen in each patient for comparison to AxioCam MRm, the median of the SNR (SNR
AxioCam
/SNRBestColorChannel
) is 84 % (Quartile 1 (Q1): 78 %, Quartile 3 (Q3): 99%). Results reveal that the integration of the Intraoperative Optical Imaging method into the OR and surgical workflow can be further improved by using RGB camera equipment. A robust identification of somato-sensory areas seems possible. Due to the gain of information from different wavelength bands the need for intelligent evaluation algorithms is increased and should therefore be topic of future research.
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Affiliation(s)
- M. Oelschlägel
- Technische Universität Dresden, Institut für Biomedizinische Technik, 01062 Dresden
| | - T. Meyer
- Technische Universität Dresden, Institut für Biomedizinische Technik, 01062 Dresden
| | - S. B. Sobottka
- Technische Universität Dresden, Institut für Biomedizinische Technik, 01062 Dresden
| | - M. Kirsch
- Technische Universität Dresden, Institut für Biomedizinische Technik, 01062 Dresden
| | - G. Schackert
- Technische Universität Dresden, Institut für Biomedizinische Technik, 01062 Dresden
| | - U. Morgenstern
- Technische Universität Dresden, Institut für Biomedizinische Technik, 01062 Dresden
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17
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Podlesek D, Meyer T, Morgenstern U, Schackert G, Kirsch M. Improved visualization of intracranial vessels with intraoperative coregistration of rotational digital subtraction angiography and intraoperative 3D ultrasound. PLoS One 2015; 10:e0121345. [PMID: 25803318 PMCID: PMC4372211 DOI: 10.1371/journal.pone.0121345] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 01/15/2015] [Indexed: 12/23/2022] Open
Abstract
Introduction Ultrasound can visualize and update the vessel status in real time during cerebral vascular surgery. We studied the depiction of parent vessels and aneurysms with a high-resolution 3D intraoperative ultrasound imaging system during aneurysm clipping using rotational digital subtraction angiography as a reference. Methods We analyzed 3D intraoperative ultrasound in 39 patients with cerebral aneurysms to visualize the aneurysm intraoperatively and the nearby vascular tree before and after clipping. Simultaneous coregistration of preoperative subtraction angiography data with 3D intraoperative ultrasound was performed to verify the anatomical assignment. Results Intraoperative ultrasound detected 35 of 43 aneurysms (81%) in 39 patients. Thirty-nine intraoperative ultrasound measurements were matched with rotational digital subtraction angiography and were successfully reconstructed during the procedure. In 7 patients, the aneurysm was partially visualized by 3D-ioUS or was not in field of view. Post-clipping intraoperative ultrasound was obtained in 26 and successfully reconstructed in 18 patients (69%) despite clip related artefacts. The overlap between 3D-ioUS aneurysm volume and preoperative rDSA aneurysm volume resulted in a mean accuracy of 0.71 (Dice coefficient). Conclusions Intraoperative coregistration of 3D intraoperative ultrasound data with preoperative rotational digital subtraction angiography is possible with high accuracy. It allows the immediate visualization of vessels beyond the microscopic field, as well as parallel assessment of blood velocity, aneurysm and vascular tree configuration. Although spatial resolution is lower than for standard angiography, the method provides an excellent vascular overview, advantageous interpretation of 3D-ioUS and immediate intraoperative feedback of the vascular status. A prerequisite for understanding vascular intraoperative ultrasound is image quality and a successful match with preoperative rotational digital subtraction angiography.
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Affiliation(s)
- Dino Podlesek
- Department of Neurosurgery, Dresden University of Technology, Carl Gustav Carus Faculty of Medicine, Dresden, Germany
| | - Tobias Meyer
- Institute of Biomedical Engineering, Dresden University of Technology, Faculty of Electrical Engineering and Information Technology, Dresden, Germany
| | - Ute Morgenstern
- Institute of Biomedical Engineering, Dresden University of Technology, Faculty of Electrical Engineering and Information Technology, Dresden, Germany
| | - Gabriele Schackert
- Department of Neurosurgery, Dresden University of Technology, Carl Gustav Carus Faculty of Medicine, Dresden, Germany
| | - Matthias Kirsch
- Department of Neurosurgery, Dresden University of Technology, Carl Gustav Carus Faculty of Medicine, Dresden, Germany
- * E-mail:
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18
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Oelschlägel M, Meyer T, Wahl H, Sobottka SB, Kirsch M, Schackert G, Morgenstern U. Evaluation of intraoperative optical imaging analysis methods by phantom and patient measurements. ACTA ACUST UNITED AC 2014; 58:257-67. [PMID: 23729532 DOI: 10.1515/bmt-2012-0077] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 04/29/2013] [Indexed: 11/15/2022]
Abstract
Intraoperative optical imaging (IOI) is a localization method for functional areas of the human brain cortex during neurosurgical procedures. The aim of the current work was to develop of a new analysis technique for the computation of two-dimensional IOI activity maps that is suited especially for use in clinical routine. The new analysis technique includes a stimulation scheme that comprises 30-s rest and 30-s stimulation conditions, in connection with pixelwise spectral power analysis for activity map calculation. A software phantom was used for verification of the implemented algorithms as well as for the comparison with the commonly used relative difference imaging method. Furthermore, the analysis technique was tested using intraoperative measurements on eight patients. The comparison with the relative difference algorithm revealed an averaged improvement of the signal-to-noise ratio between 95% and 130% for activity maps computed from intraoperatively acquired patient datasets. The results show that the new imaging technique improves the activity map quality of IOI especially under difficult intraoperative imaging conditions and is therefore especially suited for use in clinical routine.
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Affiliation(s)
- Martin Oelschlägel
- Technische Universität Dresden, Institut für Biomedizinische Technik, Dresden, Germany.
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20
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Weichelt C, Duscha P, Steinmeier R, Meyer T, Kuß J, Cimalla P, Kirsch M, Sobottka SB, Koch E, Schackert G, Morgenstern U. Quantitative fluorescence angiography for neurosurgical interventions. ACTA ACUST UNITED AC 2014; 58:269-79. [PMID: 23740655 DOI: 10.1515/bmt-2012-0078] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 05/17/2013] [Indexed: 11/15/2022]
Abstract
Present methods for quantitative measurement of cerebral perfusion during neurosurgical operations require additional technology for measurement, data acquisition, and processing. This study used conventional fluorescence video angiography--as an established method to visualize blood flow in brain vessels--enhanced by a quantifying perfusion software tool. For these purposes, the fluorescence dye indocyanine green is given intravenously, and after activation by a near-infrared light source the fluorescence signal is recorded. Video data are analyzed by software algorithms to allow quantification of the blood flow. Additionally, perfusion is measured intraoperatively by a reference system. Furthermore, comparing reference measurements using a flow phantom were performed to verify the quantitative blood flow results of the software and to validate the software algorithm. Analysis of intraoperative video data provides characteristic biological parameters. These parameters were implemented in the special flow phantom for experimental validation of the developed software algorithms. Furthermore, various factors that influence the determination of perfusion parameters were analyzed by means of mathematical simulation. Comparing patient measurement, phantom experiment, and computer simulation under certain conditions (variable frame rate, vessel diameter, etc.), the results of the software algorithms are within the range of parameter accuracy of the reference methods. Therefore, the software algorithm for calculating cortical perfusion parameters from video data presents a helpful intraoperative tool without complex additional measurement technology.
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Affiliation(s)
- Claudia Weichelt
- Institute of Biomedical Engineering, Faculty of Electrical Engineering and Information Technology, Technische Universität Dresden, Dresden, Germany.
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Meyer T, Sobottka SB, Kirsch M, Schackert G, Steinmeier R, Koch E, Morgenstern U. Intraoperative optical imaging of functional brain areas for improved image-guided surgery. ACTA ACUST UNITED AC 2014; 58:225-36. [PMID: 23729529 DOI: 10.1515/bmt-2012-0072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 04/03/2013] [Indexed: 11/15/2022]
Abstract
Intraoperative optical imaging of intrinsic signals can improve the localization of functional areas of the cortex. On the basis of a review of the current state of technology, a setup was developed and evaluated. The aim was to implement an easy-to-use and robust imaging setup that can be used in clinical routine with standard hardware equipment (surgical microscope, high-resolution camera, stimulator for peripheral nerve stimulation) and custom-made software for intraoperative and postoperative data analysis. Evaluation of different light sources (halogen, xenon) showed a sufficient temporal behavior of xenon light without using a stabilized power supply. Spatial binning (2×2) of the camera reduces temporal variations in the images by preserving a high spatial resolution. The setup was tested in eight patients. Images were acquired continuously for 9 min with alternating 30-s rest and 30-s stimulation conditions. Intraoperative measurement and visualization of high-resolution two-dimensional activity maps could be achieved in <15 min. The detected functional regions corresponded with anatomical and electrophysiological validation. The integration of optical imaging in clinical routine could successfully be achieved using standard hardware, which improves guidance for the surgeon during interventions near the eloquent areas of the brain.
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Affiliation(s)
- Tobias Meyer
- Institute of Biomedical Engineering, Faculty of Electrical Engineering and Information Technology, Dresden University of Technology, Dresden, Germany.
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Sobottka SB, Meyer T, Kirsch M, Reiss G, Koch E, Morgenstern U, Schackert G. Assessment of visual function during brain surgery near the visual cortex by intraoperative optical imaging. ACTA ACUST UNITED AC 2014; 58:249-56. [PMID: 23420282 DOI: 10.1515/bmt-2012-0074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 01/15/2013] [Indexed: 11/15/2022]
Abstract
Several functional brain imaging and mapping techniques have been used for the intraoperative identification and preservation of the sensory, motor, and speech areas of the brain. However, intraoperative monitoring and mapping of the visual function is less frequently performed in the clinical routine. To our knowledge, here we demonstrate for the first time that the individual visual cortex can be mapped to the brain surface using a contact-free optical camera system during brain surgery. Intraoperative optical imaging (IOI) was performed by visual stimulation of both eyes using stobe-light flashes. Images were acquired by a camera mounted to a standard surgical microscope. Activity maps could reproducibly be computed by detecting the blood volume-dependent signal changes of the exposed cortex. To the preliminary experience, the new technique seems to be suitable for mapping the visual function in any neurosurgical intervention that requires exposure of the visual cortex. However, the clinical relevance and reliability of the technique need to be confirmed in further studies.
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Affiliation(s)
- Stephan B Sobottka
- Department of Neurosurgery, University Hospital Carl Gustav Carus, Dresden University of Technology, Dresden, Germany.
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Sobottka SB, Meyer T, Kirsch M, Koch E, Steinmeier R, Morgenstern U, Schackert G. Intraoperative optical imaging of intrinsic signals: a reliable method for visualizing stimulated functional brain areas during surgery. J Neurosurg 2013; 119:853-63. [DOI: 10.3171/2013.5.jns122155] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Intraoperative optical imaging (IOI) is an experimental technique used for visualizing functional brain areas after surgical exposure of the cerebral cortex. This technique identifies areas of local changes in blood volume and oxygenation caused by stimulation of specific brain functions. The authors describe a new IOI method, including innovative data analysis, that can facilitate intraoperative functional imaging on a routine basis. To evaluate the reliability and validity of this approach, they used the new IOI method to demonstrate visualization of the median nerve area of the somatosensory cortex.
Methods
In 41 patients with tumor lesions adjacent to the postcentral gyrus, lesions were surgically removed by using IOI during stimulation of the contralateral median nerve. Optical properties of the cortical tissue were measured with a sensitive camera system connected to a surgical microscope. Imaging was performed by using 9 cycles of alternating prolonged stimulation and rest periods of 30 seconds. Intraoperative optical imaging was based on blood volume changes detected by using a filter at an isosbestic wavelength (λ = 568 nm). A spectral analysis algorithm was used to improve computation of the activity maps. Movement artifacts were compensated for by an elastic registration algorithm. For validation, intraoperative conduction of the phase reversal over the central sulcus and postoperative evaluation of the craniotomy site were used.
Results
The new method and analysis enabled significant differentiation (p < 0.005) between functional and nonfunctional tissue. The identification and visualization of functionally intact somatosensory cortex was highly reliable; sensitivity was 94.4% and specificity was almost 100%. The surgeon was provided with a 2D high-resolution activity map within 12 minutes. No method-related side effects occurred in any of the 41 patients.
Conclusions
The authors' new approach makes IOI a contact-free and label-free optical technique that can be used safely in a routine clinical setup. Intraoperative optical imaging can be used as an alternative to other methods for the identification of sensory cortex areas and offers the added benefit of a high-resolution map of functional activity. It has great potential for visualizing and monitoring additional specific functional brain areas such as the visual, motor, and speech cortex. A prospective national multicenter clinical trial is currently being planned.
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Affiliation(s)
| | - Tobias Meyer
- 1Department of Neurosurgery, University Hospital Carl Gustav Carus
- 2Institute for Biomedical Engineering
| | - Matthias Kirsch
- 1Department of Neurosurgery, University Hospital Carl Gustav Carus
| | - Edmund Koch
- 3Clinical Sensoring and Monitoring, Faculty of Medicine Carl Gustav Carus, Technical University of Dresden, Dresden; and
| | - Ralf Steinmeier
- 4Department of Neurosurgery, Klinikum Chemnitz gGmbH, Chemnitz, Germany
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Meyer T, Kuß J, Uhlemann F, Wagner S, Kirsch M, Sobottka SB, Steinmeier R, Schackert G, Morgenstern U. Autostereoscopic 3D visualization and image processing system for neurosurgery. ACTA ACUST UNITED AC 2013; 58:281-91. [PMID: 23740656 DOI: 10.1515/bmt-2012-0079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 05/15/2013] [Indexed: 11/15/2022]
Abstract
A demonstrator system for planning neurosurgical procedures was developed based on commercial hardware and software. The system combines an easy-to-use environment for surgical planning with high-end visualization and the opportunity to analyze data sets for research purposes. The demonstrator system is based on the software AMIRA. Specific algorithms for segmentation, elastic registration, and visualization have been implemented and adapted to the clinical workflow. Modules from AMIRA and the image processing library Insight Segmentation and Registration Toolkit (ITK) can be combined to solve various image processing tasks. Customized modules tailored to specific clinical problems can easily be implemented using the AMIRA application programming interface and a self-developed framework for ITK filters. Visualization is done via autostereoscopic displays, which provide a 3D impression without viewing aids. A Spaceball device allows a comfortable, intuitive way of navigation in the data sets. Via an interface to a neurosurgical navigation system, the demonstrator system can be used intraoperatively. The precision, applicability, and benefit of the demonstrator system for planning of neurosurgical interventions and for neurosurgical research were successfully evaluated by neurosurgeons using phantom and patient data sets.
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Affiliation(s)
- Tobias Meyer
- Institute of Biomedical Engineering, Faculty of Electrical Engineering and Information Technology, Technische Universität Dresden, Dresden, Germany.
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Oelschlägel M, Meyer T, Sobottka SB, Kirsch M, Schackert G, Morgenstern U. Phantom for Evaluation of Intraoperative Optical Imaging Setup. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- M. Oelschlägel
- Institut für Biomedizinische Technik, Technische Universität Dresden, Dresden, Deutschland
| | - T. Meyer
- Institut für Biomedizinische Technik, Technische Universität Dresden, Dresden, Deutschland
| | - S. B. Sobottka
- Klinik für Neurochirurgie, Universitätsklinikum Dresden, Dresden, Deutschland
| | - M. Kirsch
- Klinik für Neurochirurgie, Universitätsklinikum Dresden, Dresden, Deutschland
| | - G. Schackert
- Klinik für Neurochirurgie, Universitätsklinikum Dresden, Dresden, Deutschland
| | - U. Morgenstern
- Institut für Biomedizinische Technik, Technische Universität Dresden, Dresden, Deutschland
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Weichelt C, Kozusko J, Kuß J, Dietrich H, Hebestadt S, Hoffmann S, Huber L, Gottschalk S, Morgenstern U. Promoting young “MINT”-talents in pre-school and school children as future specialists in biomedical engineering. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Podlesek D, Kirsch M, Meyer T, Morgenstern U, Schackert G, Kummer RV. Long-term follow-up of Intracranial Aneurysms facilitated by three-dimensional reconstruction of DSA and MRA Imaging. KLIN NEUROPHYSIOL 2010. [DOI: 10.1055/s-0030-1250945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Hagmüller A, Schröder T, Morgenstern U, Christ M, Steinmeier R. KONTINUIERLICHES MONITORING DER ZEREBRALEN AUTOREGULATION MIT HILFE DER KREUZKORRELATION. BIOMED ENG-BIOMED TE 2009. [DOI: 10.1515/bmte.2003.48.s1.484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Schröder T, Hagmüller A, Morgenstern U, Steinmeier R. PRÄZISIERUNG UND APPLIKATION DES CUFF-DEFLATION-TESTS ZUR BEURTEILUNG DER ZEREBRALEN AUTOREGULATION. BIOMED ENG-BIOMED TE 2009. [DOI: 10.1515/bmte.2003.48.s1.336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Morgenstern U, Freyer R. WERKZEUGE UND METHODIK FÜR MULTIMEDIALE LERNSYSTEME IN BMT UND MEDIZIN – ein Beispiel zur mehrdimensionalen Datenerfassung, -verarbeitung und -visualisierung. BIOMED ENG-BIOMED TE 2009. [DOI: 10.1515/bmte.2000.45.s1.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Wagner S, Kuss J, Meyer T, Kirsch M, Morgenstern U. An integrated tool for automated visualization of subdural electrodes in epilepsy surgery evaluation. Int J Comput Assist Radiol Surg 2009; 4:609-16. [PMID: 20033337 DOI: 10.1007/s11548-009-0378-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2009] [Accepted: 06/01/2009] [Indexed: 11/30/2022]
Abstract
PURPOSE An automated tool embedded in image processing and visualization software should be developed to visualize subdural electrodes on the human cortical surface of the brain. METHODS For accurate positioning of electrodes on the cortical surface, preoperative magnetic resonance imaging (MRI) and postoperative computed tomography (CT) datasets of pharmacoresistant epilepsy patients were co-registered and segmented. For the brain segmentation of preoperative MRI a new algorithm was implemented. To account for the radial electrode displacement due to cortical deformation, a radial replacement function was developed. The automated tool was evaluated using intraoperative photographs and using a bimodal phantom. RESULTS The tool visualizes electrodes fully automated in 1-5 min. The mismatch between calculated and reference electrode position derived from intraoperative photographs was <or=9 mm, and was based upon phantom data <or=1.6 mm. CONCLUSIONS Empirical investigations have to be made to quantify the magnitude and the nature of transverse electrode displacement in order to investigate the practicability and to determine the accuracy of the developed tool. Depending on investigation results, a half-automated intraoperative photography based method might be an option to minimize electrode shift.
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Affiliation(s)
- Stefan Wagner
- Institut für Biomedizinische Technik, Technische Universität Dresden, Dresden, Germany.
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Abstract
Cerebral autoregulation (CA) is a control mechanism that adjusts cerebral vasomotor tone in response to changes in arterial blood pressure (ABP) to ensure a nearly constant cerebral blood flow. Patient treatment could be optimized if CA monitoring were possible. Whereas the concept of static CA assessment is simply based on comparison of mean values obtained from two stationary states (e.g., before and after a pressure change), the evaluation of dynamic CA is more complex. Among other methods, moving cross-correlation analysis of slow waves in ABP and cerebral blood flow velocity (CBFV) seems to be appropriate to monitor CA quasi-continuously. The calculation of an "instantaneous transfer function" between ABP and CBFV oscillations in the low-frequency band using the Wigner-Ville distribution may represent an acceptable compromise in time-frequency resolution for continuous CA monitoring.
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Affiliation(s)
- Frank Noack
- Institute of Biomedical Engineering, Dresden University of Technology, Dresden, Germany.
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Kirsch M, Meyer T, Podlesek D, Morgenstern U, von Kummer R, Schackert G. Improved Planning of Skull Base Surgery by Coregistration of Three-Dimensional Data Sets of Different Angiographic Imaging Modalities Including rDSA, MRA, CTA, and T1-MRI Volume Data. Skull Base 2007. [DOI: 10.1055/s-2007-984061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Christ M, Noack F, Schroeder T, Hagmueller A, Koch R, May SA, Morgenstern U, Ragaller M, Steinmeier R. Continuous cerebral autoregulation monitoring by improved cross-correlation analysis: comparison with the cuff deflation test. Intensive Care Med 2006; 33:246-54. [PMID: 17143638 DOI: 10.1007/s00134-006-0451-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2005] [Accepted: 10/17/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVES To improve the cross-correlation method for noninvasive, continuous monitoring of cerebral autoregulation, to evaluate this method in humans with intact and impaired autoregulatory capacity, and to compare it to the cuff deflation test. DESIGN AND SETTING Prospective study in the intensive care unit of a university hospital. PATIENTS AND PARTICIPANTS Fourteen patients with severe head injury, six patients with subarachnoid hemorrhage, and nine healthy volunteers. INTERVENTIONS AND MEASUREMENTS Middle cerebral artery flow velocities and arterial blood pressure were monitored continuously. Aaslid's thigh cuff tests were performed and results were scored using Tiecks' model for autoregulation index. Data were then collected without any patient manipulation. The mean time delay between slow spontaneous oscillations of blood pressure and middle cerebral artery flow velocity was calculated by cross-correlation analysis. Data are expressed as median (lower/upper quartile). RESULTS Healthy subjects had a higher autoregulation index than patients, 5.0 (5.0/5.5) vs. 3.3 (2.0/4.5). Slow oscillations of blood pressure and middle cerebral artery flow velocity showed a time delay of -2.0 s (-2.7/-1.7) in healthy subjects but were almost synchronal in patients, -0.07 s (-0.5/0.45). Inter-method agreement in diagnosing an intact or impaired cerebral autoregulation was obtained in 108 of 147 examinations of autoregulation (73.5%) and was considered moderate. CONCLUSIONS Cross-correlation analysis may serve as a simple, noninvasive, and continuous measure of cerebral autoregulation. The time delay of -2.0[Symbol: see text]s in healthy subjects is in good agreement with other studies. Short-term autoregulation tests and monitoring techniques based on slow spontaneous oscillations should not be used interchangeably.
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Affiliation(s)
- Melanie Christ
- Department of Anesthesiology and Intensive Care Medicine, Carl Gustav Carus University Hospital, Technical University of Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
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Sergeeva O, Uhlemann F, Schackert G, Hergeth C, Morgenstern U, Steinmeier R. Integration of intraoperative 3D-ultrasound in a commercial navigation system. ACTA ACUST UNITED AC 2006; 67:197-203. [PMID: 17106832 DOI: 10.1055/s-2006-942186] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
STUDY AIMS The purpose of this study was the integration of three-dimensional ultrasound data into a neuronavigation system, in order to allow a guided intraoperative resection control during neurosurgical interventions. MATERIAL AND METHODS A system for iterative neuronavigation based on 3D-ultrasound (US) has been developed. The main components of the system are the ultrasound device Voluson 730 (GE Healthcare) with a 5 - 9 MHz probe, the navigation system VectorVision2 (BrainLAB AG) and a standard PC with Windows XP. The ultrasound data are transferred via DICOM from the ultrasound device to an external computer, where they are processed with a C++ program for representation in the neuronavigation coordinate system. The data transfer between the navigation system and the external computer is performed via the VVLink interface from BrainLAB. The feasibility test of the system was performed with an ultrasound phantom RMI 403GS (Gammex-RMI GmbH). RESULTS The error of homologous points mapping from US datasets to a CT dataset in the neuronavigation system was determined to be 1.9 +/- 0.97 mm. The maximum time required to technically integrate the ultrasound data into the navigation system was 1.5 min. CONCLUSIONS The developed system allows 3D-ultrasound based navigation to be carried out with a commercially available navigation system. The functionality of this system has been proven by technical tests. Recording and integration of the ultrasound data can be repeated at any time during surgery and can be used to update anatomical data and consequently for resection control. Another application is the intraoperative adaptation of preoperative datasets (MRI or CT) in order to compensate for "brain shift" during neurosurgical operations.
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Affiliation(s)
- O Sergeeva
- Institut für Biomedizinische Technik, Technische Universität Dresden, Germany.
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Bickhardt J, Fuchs M, Morgenstern U. Variabilität von Parametern bei Heimbeatmungsgeräten. Pneumologie 2005. [DOI: 10.1055/s-2004-831114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Bickhardt J, Fuchs M, Morgenstern U. Variabilität von Parametern bei Heimbeatmungsgeräten. Pneumologie 2004. [DOI: 10.1055/s-2004-831151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Uhlemann F, Morgenstern U, Steinmeier R. Objective evaluation of three-dimensional image registration algorithms--tools for optimization and evaluation. Methods Inf Med 2004; 43:367-70. [PMID: 15472748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
OBJECTIVE The registration of medical volume data sets plays an important role when different images or modalities are used during computer-assisted surgical procedures. Nevertheless, it is often questionable how robust and accurate the underlying algorithms really are. Therefore, the goal is to foster the establishment of methods for an objective evaluation. METHOD To reliably calculate the accuracy of registration algorithms, a reference transformation must be known. Due to the unknown perfect registration for real clinical data, the simulation of realistic data and successive affine transformations are employed. The simulation is based on models of the respective imaging modality where the dominant physical effects are taken into account. This gives the user full control over all simulation and transformation parameters. Finally, suitable quality measures are applied which allow a systematic evaluation of image registration accuracy by comparing the known theoretical result and the transformation calculated by the algorithm under investigation. RESULTS During the development of a new registration algorithm, the presented method proved to be a very valuable tool for optimization and evaluation of registration accuracy, since it allows objective numerical comparison of the calculated results. CONCLUSIONS The presented method can be used during the development of algorithms for optimization and for quantitative comparison of different registration schemes. The respective software tool can automatically generate and transform simulated but realistic data. Employing suitable numerical quality measures, an objective evaluation of registration results can be easily obtained. Still, the validity of the relatively simple models has to be verified to draw reliable conclusions with respect to real data.
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Affiliation(s)
- F Uhlemann
- Image Processing and Recognition Group, Institute of Artificial Intelligence, Department of Computer Science, Dresden University of Technology, Dresden, Germany.
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Fuchs M, Bickhardt J, Morgenstern U. [Variability of ventilation parameters of home ventilation equipment]. BIOMED ENG-BIOMED TE 2003; 47 Suppl 1 Pt 2:845-8. [PMID: 12465320 DOI: 10.1515/bmte.2002.47.s1b.845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The performance of pressure- and volume controlled ventilators used for invasive and non-invasive ventilation in the home were tested on a patient lung model. In order to determine the influence of tidal volume preset, breathing rate, resistance, compliance and leakage to the variability of delivered tidal volume and peak airway pressure a factorial plan with adapted analysis of variance was used. The influence of tidal volume preset, compliance and leakage to the delivered tidal volume is significant. The peak airway pressure depends hardly on the influence factors. All tested ventilators meet the legal demands. But in some clinical situations there are considerable deviations of the breathing parameters depending on the brand. In conclusion ventilators of different brands are not interchangeable.
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Affiliation(s)
- M Fuchs
- Institut für Biomedizinische Technik, Technische Universität Dresden, Deutschland.
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Uhlemann F, Morgenstern U, Sobottka S, Steinmeier R. [Comparison of the accuracy of 3-dimensional fusion algorithms]. BIOMED ENG-BIOMED TE 2003; 47 Suppl 1 Pt 2:626-8. [PMID: 12465257 DOI: 10.1515/bmte.2002.47.s1b.626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Recently many algorithms for matching three-dimensional medical data have been developed. Inter- and intramodal fusion of data adds valuable information for planning, controlling and evaluating therapies. This work presents a procedure to evaluate the accuracy of fusion algorithms by numerical means. In contrast to the usual way of visual inspection the developed software tools allow automatic numerical--and thus objective--evaluation of different algorithms using simulated realistic volume data. It is therefore possible to conduct reproducible comparisons of different matching methods. These tools also proved to be very valuable during the development and optimisation of an algorithm employing normalised mutual information.
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Affiliation(s)
- F Uhlemann
- Institut für Biomedizinische Technik, Technische Universität Dresden, Deutschland.
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41
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Hagmüller A, Morgenstern U, Schröder T, Steinmeier R. [Integration of the Aasalid test in an online measurement system for evaluating cerebral autoregulation]. BIOMED ENG-BIOMED TE 2003; 47 Suppl 1 Pt 2:592-5. [PMID: 12465246 DOI: 10.1515/bmte.2002.47.s1b.592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
An important question during the intensive care of patients with subarachnoid hemorrhage and craniocerebral trauma is the evaluation of the cerebral autoregulation (CA). The so called Aaslid-Test is a standard method which allows the cerebral autoregulation to be classified. As the results under repetitive conditions show a high variation, it has not been yet possible to draw statistically proved conclusions concerning the performance of the CA. To improve the test results the measuring conditions are discussed and systematized. The algorithms of the Aaslid-Test have been implemented to an online measuring system. The error bandwidth has been estimated. To avoid systematically occurring errors an enhanced measuring protocol is provided.
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Affiliation(s)
- A Hagmüller
- Institut für Biomedizinische Technik, TU Dresden, Deutschland.
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Uhlemann F, Morgenstern U, Freyer R. SEGMENTIERUNG, VOLUMENBESTIMMUNG UND VISUALISIERUNG MEDIZINISCHER DATEN VERSCHIEDENER MODALITÄTEN. BIOMED ENG-BIOMED TE 2000. [DOI: 10.1515/bmte.2000.45.s1.473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Povinec PP, Woodhead D, Blowers P, Bonfield R, Cooper M, Chen Q, Dahlgaard H, Dovlete C, Fox V, Froehlich K, Gastaud J, Gröning M, Hamilton T, Ikeuchi Y, Kanisch G, Krüger A, Kwong LL, Matthews M, Morgenstern U, Mulsow S, Pettersson H, Smedley P, Taylor B, Taylor C, Tinker R. Marine radioactivity assessment of Mururoa and Fangataufa atolls. Sci Total Environ 1999; 237-238:249-67. [PMID: 10568280 DOI: 10.1016/s0048-9697(99)00140-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
The International Atomic Energy Agency (IAEA) carried out an international project. 'The Study of the Radiological Situation at the Atolls of Mururoa and Fangataufa' with the aim of assessing the present and future radiological situation at the atolls and making recommendations for either monitoring or remedial actions if they are deemed necessary. The paper concentrates on marine radioactivity aspects and gives an estimation of present radionuclide concentrations in water, sediment and biota of the Mururoa and Fangataufa lagoons and the surrounding ocean. The dominant radionuclide in both lagoons is Pu in sediments (the total inventory is approximately 30 TBq). A decline in radionuclide concentrations has been observed in recent years in lagoon water, with the exception of 3H and 90Sr, for which a contribution from underground sources is to be expected. Radionuclide concentrations in biota from the lagoons and the surrounding ocean are low and consistent with previous measurements. The observed radionuclide concentrations in both lagoons imply that no radiological risk exists for hypothetical inhabitants of Mururoa and Fangataufa Atolls.
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Affiliation(s)
- P P Povinec
- Marine Environment Laboratory, International Atomic Energy Agency, Monaco.
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Morgenstern U, Freyer R. [Education in biomedical technique: past--why--future?]. BIOMED ENG-BIOMED TE 1998; 43 Suppl:460-1. [PMID: 9859442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- U Morgenstern
- Institut für Biomedizinische Technik, Technische Universität Dresden
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45
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Morgenstern U, Freyer R. [Visualization of medical data using the Dresden Autostereoscopic Display]. BIOMED ENG-BIOMED TE 1998; 42 Suppl:341-2. [PMID: 9517182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- U Morgenstern
- Fakultät Elektrotechnik, Institut für Biomedizinische Technik, Technische Universität Dresden
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46
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Kühn H, Kaiser D, Morgenstern U, Schwerdtner A, Daniel WG, Freyer R. [Presentation of three-dimensional echocardiography with the Dresden autostereoscopic display]. BIOMED ENG-BIOMED TE 1998; 42 Suppl:422-3. [PMID: 9517219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- H Kühn
- Universitätsklinikum Carl Gustav Carus, II. Medizinische Klinik, Technische Universität Dresden
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47
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Kühn H, Kaiser D, Morgenstern U, Schwerdtner A, Daniel WG, Freyer R. Darstellung dreidimensionaler Echokardiographie mit dem Dresdner Autostereoskopischem Display. BIOMED ENG-BIOMED TE 1997. [DOI: 10.1515/bmte.1997.42.s2.422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
Routine application of 'rule of thumb' parameter sets in clinical practice pushes model visions to the background, including the complete framework of assumptions, simplifications, suppositions and conditions. But: models can be very strong tool, when applied selectively--that means, with a clear idea of destination, definition, parameter selection and verification. This article discusses universal issues of modelling--based on ventilation mechanics models in intensive care medicine.
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Affiliation(s)
- U Morgenstern
- Technische Universität Dresden, Fakultät Elektrotechnik, Institut für Biomedizinische Technik, Germany
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