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Göbel-Guéniot K, Gerlach J, Kamberger R, Leupold J, von Elverfeldt D, Hennig J, Korvink JG, Haas CA, LeVan P. Corrigendum: Histological Correlates of Diffusion-Weighted Magnetic Resonance Microscopy in a Mouse Model of Mesial Temporal Lobe Epilepsy. Front Neurosci 2020; 14:806. [PMID: 32973426 PMCID: PMC7466631 DOI: 10.3389/fnins.2020.00806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 07/09/2020] [Indexed: 11/19/2022] Open
Affiliation(s)
- Katharina Göbel-Guéniot
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Johannes Gerlach
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Freiburg, Germany
| | - Robert Kamberger
- Department of Microsystems Engineering, Technical Faculty, University of Freiburg, Freiburg, Germany
| | - Jochen Leupold
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Dominik von Elverfeldt
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jürgen Hennig
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jan G Korvink
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Carola A Haas
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Freiburg, Germany.,BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Pierre LeVan
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany.,Department of Radiology and Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
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2
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Göbel-Guéniot K, Gerlach J, Kamberger R, Leupold J, von Elverfeldt D, Hennig J, Korvink JG, Haas CA, LeVan P. Histological Correlates of Diffusion-Weighted Magnetic Resonance Microscopy in a Mouse Model of Mesial Temporal Lobe Epilepsy. Front Neurosci 2020; 14:543. [PMID: 32581687 PMCID: PMC7284165 DOI: 10.3389/fnins.2020.00543] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 03/09/2020] [Accepted: 05/04/2020] [Indexed: 12/20/2022] Open
Abstract
Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy. It is frequently associated with abnormal MRI findings, which are caused by underlying cellular, structural, and chemical changes at the micro-scale. In the current study, it is investigated to which extent these alterations correspond to imaging features detected by high resolution magnetic resonance imaging in the intrahippocampal kainate mouse model of MTLE. Fixed hippocampal and whole-brain sections of mouse brain tissue from nine animals under physiological and chronically epileptic conditions were examined using structural and diffusion-weighted MRI. Microstructural details were investigated based on a direct comparison with immunohistochemical analyses of the same specimen. Within the hippocampal formation, diffusion streamlines could be visualized corresponding to dendrites of CA1 pyramidal cells and granule cells, as well as mossy fibers and Schaffer collaterals. Statistically significant changes in diffusivities, fractional anisotropy, and diffusion orientations could be detected in tissue samples from chronically epileptic animals compared to healthy controls, corresponding to microstructural alterations (degeneration of pyramidal cells, dispersion of the granule cell layer, and sprouting of mossy fibers). The diffusion parameters were significantly correlated with histologically determined cell densities. These findings demonstrate that high-resolution diffusion-weighted MRI can resolve subtle microstructural changes in epileptic hippocampal tissue corresponding to histopathological features in MTLE.
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Affiliation(s)
- Katharina Göbel-Guéniot
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Johannes Gerlach
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Experimental Epilepsy Research, Department of Neurosurgery, Medical Center – University of Freiburg, Freiburg, Germany
| | - Robert Kamberger
- Department of Microsystems Engineering, Technical Faculty, University of Freiburg, Freiburg, Germany
| | - Jochen Leupold
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Dominik von Elverfeldt
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jürgen Hennig
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jan G Korvink
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Carola A Haas
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Experimental Epilepsy Research, Department of Neurosurgery, Medical Center – University of Freiburg, Freiburg, Germany,BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Pierre LeVan
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany.,Department of Radiology and Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
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3
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Schnoz S, Hunkeler A, Däpp A, Kamberger R, Korvink JG, Meier BH. Microscale 3D imaging by magnetic resonance force microscopy using full-volume Fourier- and Hadamard-encoding. J Magn Reson 2019; 299:196-201. [PMID: 30677601 DOI: 10.1016/j.jmr.2019.01.005] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 06/09/2023]
Abstract
Three-dimensional spatially resolved full-volume imaging by magnetic resonance force microscopy at room temperature is described. Spatial resolution in z-dimension is achieved by using the magnetic-field gradient of a ferromagnetic particle that is also used for the force detection of the magnetic resonance. The gradient of the radiofrequency pulses generated by two separate wire-bonded microcoils is used for spatial resolution in x- and y-dimension. To enhance the sensitivity of our measurement Hadamard- and Fourier-encoding schemes are applied due to their multiplex effect. Measurements were taken on a patterned (NH4)2SO4 crystal sample. From the calculated magnetic field distributions, a 3D image was reconstructed with a voxel volume of about 5 μm3 (1.2 μm × 3.0 μm × 1.4 μm in x-, y- and z-dimension).
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Affiliation(s)
- Sebastian Schnoz
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Andreas Hunkeler
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Alexander Däpp
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Robert Kamberger
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Georges-Koehler-Allee 80, 79110 Freiburg, Germany
| | - Jan G Korvink
- Institute of Microstructure Technology, KIT, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Beat H Meier
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland.
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4
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Kamberger R, Göbel-Guéniot K, Gerlach J, Gruschke OG, Hennig J, LeVan P, Haas C, Korvink JG. Improved method for MR microscopy of brain tissue cultured with the interface method combined with Lenz lenses. Magn Reson Imaging 2018; 52:24-32. [PMID: 29857037 DOI: 10.1016/j.mri.2018.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 05/21/2018] [Accepted: 05/21/2018] [Indexed: 12/17/2022]
Abstract
MR in microscopy can non-invasively image the morphology of living tissue, which is of particular interest in studying the mammalian brain. Many studies use live animals for basic research on brain functions, disease pathogenesis, and drug development. However, in vitro systems are on the rise, due to advantages such as the absence of a blood-brain barrier, predictable pharmacokinetics, and reduced ethical restrictions. Hence, they present an inexpensive and adequate technique to answer scientific questions and to perform drug screenings. Some publications report the use of acute brain slices for MR microscopy studies, but these only permit single measurements over several hours. Repetitive MR measurements in longitudinal studies demand an MR-compatible setup which allows cultivation for several days or weeks, and hence properly functioning in vitro systems. Organotypic hippocampal slice cultures (OHSC) are a well-established and robust in vitro system which still exhibits most histological hallmarks of the hippocampal network in vivo. An MR compatible incubation platform is introduced in which OHSC are cultivated according to the interface method following Stoppini et al. In this cultivation method a tissue slice is placed onto a membrane with nutrition medium underneath and a gas atmosphere above, where the air-tissue interface perpendicular to the B0 field induces strong artefacts. We introduce a handling protocol that suppresses these artefacts and increases signal quality significantly to acquire high resolution images of tissue slices. An additional challenge is the lack of available of MR microscopy equipment suitable for small animal scanners. A Lenz lens with an attached capacitor can dramatically increase the SNR in these cases, and wirelessly bring the detection system in close proximity to the sample without compromising the OHSC system through the introduction of wired detectors. The resultant signal gain is demonstrated by imaging a PFA-fixed brain slice with a 72 mm diameter volume coil without a Lenz lens, and with a broadband and a self-resonant Lenz lens. In our setting, the self-resonant Lenz lens increases the SNR 10-fold over using the volume coil only.
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Affiliation(s)
- R Kamberger
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany
| | - K Göbel-Guéniot
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany; Medical Physics, Department of Radiology, Medical Center - University of Freiburg, Germany
| | - J Gerlach
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany; Experimental Epilepsy Laboratory, Department of Neurosurgery, Medical Center - University of Freiburg, Germany
| | - O G Gruschke
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Germany
| | - J Hennig
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany; Medical Physics, Department of Radiology, Medical Center - University of Freiburg, Germany
| | - P LeVan
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany; Medical Physics, Department of Radiology, Medical Center - University of Freiburg, Germany
| | - C Haas
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany; Experimental Epilepsy Laboratory, Department of Neurosurgery, Medical Center - University of Freiburg, Germany
| | - J G Korvink
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Germany.
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5
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Traser L, Birkholz P, Flügge TV, Kamberger R, Burdumy M, Richter B, Korvink JG, Echternach M. Relevance of the Implementation of Teeth in Three-Dimensional Vocal Tract Models. J Speech Lang Hear Res 2017; 60:2379-2393. [PMID: 28898358 DOI: 10.1044/2017_jslhr-s-16-0395] [Citation(s) in RCA: 5] [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] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 02/23/2017] [Indexed: 06/07/2023]
Abstract
PURPOSE Recently, efforts have been made to investigate the vocal tract using magnetic resonance imaging (MRI). Due to technical limitations, teeth were omitted in many previous studies on vocal tract acoustics. However, the knowledge of how teeth influence vocal tract acoustics might be important in order to estimate the necessity of implementing teeth in vocal tract models. The aim of this study was therefore to estimate the effect of teeth on vocal tract acoustics. METHOD The acoustic properties of 18 solid (3-dimensional printed) vocal tract models without teeth were compared to the same 18 models including teeth in terms of resonance frequencies (fRn). The fRn were obtained from the transfer functions of these models excited by white noise at the glottis level. The models were derived from MRI data of 2 trained singers performing 3 different vowel conditions (/i/, /a/, and /u/) in speech and low-pitched and high-pitched singing. RESULTS Depending on the oral configuration, models exhibiting side cavities or side branches were characterized by major changes in the transfer function when teeth were implemented via the introduction of pole-zero pairs. CONCLUSIONS To avoid errors in modeling, teeth should be included in 3-dimensional vocal tract models for acoustic evaluation. SUPPLEMENTAL MATERIAL https://doi.org/10.23641/asha.5386771.
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Affiliation(s)
- Louisa Traser
- Institute of Musicians' Medicine, Freiburg University Medical Center, Germany
- Department of Otolaryngology, Freiburg University Medical Center, Germany
- Faculty of Medicine, University of Freiburg, Germany
| | - Peter Birkholz
- Institute of Acoustics and Speech Communication, Technische Universität, Dresden, Germany
| | - Tabea Viktoria Flügge
- Faculty of Medicine, University of Freiburg, Germany
- Department of Craniomaxillofacial Surgery, Freiburg University Medical Center, Germany
| | - Robert Kamberger
- Laboratory of Simulation, Department of Microsystems Engineering-IMTEK, University of Freiburg, Germany
| | - Michael Burdumy
- Faculty of Medicine, University of Freiburg, Germany
- Department of Medical Physics, Radiology, Freiburg University Medical Center, Germany
| | - Bernhard Richter
- Institute of Musicians' Medicine, Freiburg University Medical Center, Germany
- Faculty of Medicine, University of Freiburg, Germany
| | - Jan Gerrit Korvink
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Matthias Echternach
- Institute of Musicians' Medicine, Freiburg University Medical Center, Germany
- Faculty of Medicine, University of Freiburg, Germany
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6
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Jouda M, Kamberger R, Leupold J, Spengler N, Hennig J, Gruschke O, Korvink JG. A comparison of Lenz lenses and LC resonators for NMR signal enhancement. Concepts Magn Reson Part B Magn Reson Eng 2017; 47B:e21357. [PMID: 29541005 PMCID: PMC5839471 DOI: 10.1002/cmr.b.21357] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/11/2017] [Accepted: 10/26/2017] [Indexed: 06/09/2023]
Abstract
High signal-to-noise ratio (SNR) of the NMR signal has always been a key target that drives massive research effort in many fields. Among several parameters, a high filling factor of the MR coil has proven to boost the SNR. In case of small-volume samples, a high filling factor and thus a high SNR can be achieved through miniaturizing the MR coil. However, under certain circumstances, this can be impractical. In this paper, we present an extensive theoretical and experimental investigation of the inductively coupled LC resonator and the magnetic Lenz lens as two candidate approaches that can enhance the SNR in such circumstances. The results demonstrate that the narrow-band LC resonator is superior in terms of SNR, while the non-tuned nature of the Lenz lens makes it preferable in broadband applications.
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Affiliation(s)
- Mazin Jouda
- Karlsruhe Institute of Technology‐KITInstitute of Microstructure Technology‐IMTEggenstein‐LeopoldshafenGermany
| | - Robert Kamberger
- BrainLinks‐BrainTools Cluster of ExcellenceInstitute of Microsystems Technology‐IMTEKUniversity of FreiburgFreiburgGermany
| | - Jochen Leupold
- Department of RadiologyMedical PhysicsMedical Center ‐ University of FreiburgFaculty of MedicineUniversity of FreiburgFreiburgGermany
| | | | - Jürgen Hennig
- Department of RadiologyMedical PhysicsMedical Center ‐ University of FreiburgFaculty of MedicineUniversity of FreiburgFreiburgGermany
| | | | - Jan G. Korvink
- Karlsruhe Institute of Technology‐KITInstitute of Microstructure Technology‐IMTEggenstein‐LeopoldshafenGermany
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Echternach M, Birkholz P, Traser L, Flügge TV, Kamberger R, Burk F, Burdumy M, Richter B. Articulation and vocal tract acoustics at soprano subject's high fundamental frequencies. J Acoust Soc Am 2015; 137:2586-2595. [PMID: 25994691 DOI: 10.1121/1.4919356] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The role of the vocal tract for phonation at very high soprano fundamental frequencies (F0s) is not yet understood in detail. In this investigation, two experiments were carried out with a single professional high soprano subject. First, using two dimensional (2D) dynamic real-time magnetic resonance imaging (MRI) (24 fps) midsagittal and coronal vocal tract shapes were analyzed while the subject sang a scale from Bb5 (932 Hz) to G6 (1568 Hz). In a second experiment, volumetric vocal tract MRI data were recorded from sustained phonations (13 s) for the pitches C6 (1047 Hz) and G6 (1568 Hz). Formant frequencies were measured in physical models created by 3D printing, and calculated from area functions obtained from the 3D vocal tract shapes. The data showed that there were only minor modifications of the vocal tract shape. These changes involved a decrease of the piriform sinus as well as small changes of tongue position. Formant frequencies did not exhibit major differences between C6 and G6 for F1 and F3, respectively. Only F2 was slightly raised for G6. For G6, however, F2 is not excited by any voice source partial. Therefore, this investigation was not able to confirm that the analyzed professional soprano subject adjusted formants to voice source partials for the analyzed F0s.
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Affiliation(s)
- Matthias Echternach
- Institute of Musicians' Medicine, Freiburg University Medical Center, Breisacher Str. 60, 79106 Freiburg, Germany
| | - Peter Birkholz
- Institute of Acoustics and Speech Communication, Technische Universität Dresden, Dresden, 01062 Dresden, Germany
| | - Louisa Traser
- Institute of Musicians' Medicine, Freiburg University Medical Center, Breisacher Str. 60, 79106 Freiburg, Germany
| | - Tabea V Flügge
- Department of Craniomaxillofacial Surgery, Freiburg University Medical Center, Hugstetterstr. 55, 79106 Freiburg, Germany
| | - Robert Kamberger
- Laboratory of Simulation, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges-Köhler-Allee 102, 79110 Freiburg, Germany
| | - Fabian Burk
- Institute of Musicians' Medicine, Freiburg University Medical Center, Breisacher Str. 60, 79106 Freiburg, Germany
| | - Michael Burdumy
- Department of Radiology, Medical Physics, Freiburg University Medical Center, Breisacher Str. 60a, 79106 Freiburg, Germany
| | - Bernhard Richter
- Institute of Musicians' Medicine, Freiburg University Medical Center, Breisacher Str. 60, 79106 Freiburg, Germany
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Schneider F, Draheim J, Kamberger R, Waibel P, Wallrabe U. Optical characterization of adaptive fluidic silicone-membrane lenses. Opt Express 2009; 17:11813-21. [PMID: 19582096 DOI: 10.1364/oe.17.011813] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We present an extended optical characterization of an adaptive microfluidic silicone-membrane lens at a wavelength of 633 nm, respectively 660 nm. Two different membrane variations; one with a homogeneous membrane thickness, and one with a shaped cross section, have been realized. This paper includes the theoretical predictions of the optical performance via FEM simulation and ray tracing, and a subsequent orientation dependent experimental analysis of the lens quality which is measured with an MTF setup and a Mach-Zehnder interferometer. The influence of the fabrication process on the optical performance is also characterized by the membrane deformation in the non-deflected state. The lens with the homogeneous membrane of 5 mm in diameter and an aperture of 2.5 mm indicates an almost orientation independent image quality of 117 linepairs/mm at a contrast of 50%. The shaped membrane lenses show a minimum wave front error of WFE(RMS) = 24 nm, and the lenses with a planar membrane of WFE(RMS) = 31 nm at an aperture of 2.125 mm.
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Affiliation(s)
- Florian Schneider
- Department of Microsystems Engineering - IMTEK, Laboratory for Microactuators, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany.
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