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Munder T, Pfeffer A, Schreyer S, Guo J, Braun J, Sack I, Steiner B, Klein C. MR elastography detection of early viscoelastic response of the murine hippocampus to amyloid β accumulation and neuronal cell loss due to Alzheimer's disease. J Magn Reson Imaging 2017; 47:105-114. [DOI: 10.1002/jmri.25741] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/03/2017] [Indexed: 12/22/2022] Open
Affiliation(s)
- Tonia Munder
- Department of Neurology; Charité - University Medicine Berlin; Berlin Germany
| | - Anna Pfeffer
- Department of Neurology; Charité - University Medicine Berlin; Berlin Germany
| | - Stefanie Schreyer
- Department of Neurology; Charité - University Medicine Berlin; Berlin Germany
| | - Jing Guo
- Department of Radiology; Charité - University Medicine Berlin; Berlin Germany
| | - Juergen Braun
- Institute for Medical Informatics; Charité - University Medicine Berlin; Berlin Germany
| | - Ingolf Sack
- Department of Radiology; Charité - University Medicine Berlin; Berlin Germany
| | - Barbara Steiner
- Department of Neurology; Charité - University Medicine Berlin; Berlin Germany
| | - Charlotte Klein
- Department of Neurology; Charité - University Medicine Berlin; Berlin Germany
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52
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Schwarb H, Johnson CL, Daugherty AM, Hillman CH, Kramer AF, Cohen NJ, Barbey AK. Aerobic fitness, hippocampal viscoelasticity, and relational memory performance. Neuroimage 2017; 153:179-188. [PMID: 28366763 PMCID: PMC5637732 DOI: 10.1016/j.neuroimage.2017.03.061] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/09/2017] [Accepted: 03/29/2017] [Indexed: 12/13/2022] Open
Abstract
The positive relationship between hippocampal structure, aerobic fitness, and memory performance is often observed among children and older adults; but evidence of this relationship among young adults, for whom the hippocampus is neither developing nor atrophying, is less consistent. Studies have typically relied on hippocampal volumetry (a gross proxy of tissue composition) to assess individual differences in hippocampal structure. While volume is not specific to microstructural tissue characteristics, microstructural differences in hippocampal integrity may exist even among healthy young adults when volumetric differences are not diagnostic of tissue health or cognitive function. Magnetic resonance elastography (MRE) is an emerging noninvasive imaging technique for measuring viscoelastic tissue properties and provides quantitative measures of tissue integrity. We have previously demonstrated that individual differences in hippocampal viscoelasticity are related to performance on a relational memory task; however, little is known about health correlates to this novel measure. In the current study, we investigated the relationship between hippocampal viscoelasticity and cardiovascular health, and their mutual effect on relational memory in a group of healthy young adults (N=51). We replicated our previous finding that hippocampal viscoelasticity correlates with relational memory performance. We extend this work by demonstrating that better aerobic fitness, as measured by VO2max, was associated with hippocampal viscoelasticity that mediated the benefits of fitness on memory function. Hippocampal volume, however, did not account for individual differences in memory. Therefore, these data suggest that hippocampal viscoelasticity may provide a more sensitive measure to microstructural tissue organization and its consequences to cognition among healthy young adults.
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Affiliation(s)
- Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N. Mathews Ave, Urbana, IL 61081, USA.
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, 150 Academy Street, 161 Colburn Lab, Newark, DE 19716, USA
| | - Ana M Daugherty
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N. Mathews Ave, Urbana, IL 61081, USA
| | - Charles H Hillman
- Department of Psychology, Northeastern University, 125 Nightingale Hall, 360 Huntington Ave., Boston, MA 02115, USA
| | - Arthur F Kramer
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N. Mathews Ave, Urbana, IL 61081, USA; Department of Psychology, Northeastern University, 125 Nightingale Hall, 360 Huntington Ave., Boston, MA 02115, USA
| | - Neal J Cohen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N. Mathews Ave, Urbana, IL 61081, USA
| | - Aron K Barbey
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N. Mathews Ave, Urbana, IL 61081, USA; Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel St, Champaign, IL 61820, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, 405 N. Mathews Ave, Urbana, IL 61081, USA; Department of Internal Medicine, University of Illinois at Urbana-Champaign, 506 S. Mathews Ave, Urbana, IL 61801, USA; Department of Bioengineering, University of Illinois at Urbana-Champaign, 1304 W. Springfield Ave, Urbana, IL 61801, USA; Carle R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 W. Gregory Dr, Urbana, IL 61801, USA.
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53
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Forte AE, Gentleman SM, Dini D. On the characterization of the heterogeneous mechanical response of human brain tissue. Biomech Model Mechanobiol 2016; 16:907-920. [PMID: 27933417 PMCID: PMC5422507 DOI: 10.1007/s10237-016-0860-8] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 11/21/2016] [Indexed: 01/19/2023]
Abstract
The mechanical characterization of brain tissue is a complex task that scientists have tried to accomplish for over 50 years. The results in the literature often differ by orders of magnitude because of the lack of a standard testing protocol. Different testing conditions (including humidity, temperature, strain rate), the methodology adopted, and the variety of the species analysed are all potential sources of discrepancies in the measurements. In this work, we present a rigorous experimental investigation on the mechanical properties of human brain, covering both grey and white matter. The influence of testing conditions is also shown and thoroughly discussed. The material characterization performed is finally adopted to provide inputs to a mathematical formulation suitable for numerical simulations of brain deformation during surgical procedures.
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Affiliation(s)
- Antonio E Forte
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK.
| | | | - Daniele Dini
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK
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54
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Hiscox LV, Johnson CL, Barnhill E, McGarry MDJ, Huston J, van Beek EJR, Starr JM, Roberts N. Magnetic resonance elastography (MRE) of the human brain: technique, findings and clinical applications. Phys Med Biol 2016; 61:R401-R437. [DOI: 10.1088/0031-9155/61/24/r401] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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55
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Fehlner A, Hirsch S, Weygandt M, Christophel T, Barnhill E, Kadobianskyi M, Braun J, Bernarding J, Lützkendorf R, Sack I, Hetzer S. Increasing the spatial resolution and sensitivity of magnetic resonance elastography by correcting for subject motion and susceptibility-induced image distortions. J Magn Reson Imaging 2016; 46:134-141. [DOI: 10.1002/jmri.25516] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 10/05/2016] [Indexed: 12/13/2022] Open
Affiliation(s)
- Andreas Fehlner
- Department of Radiology; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Sebastian Hirsch
- Institute of Medical Informatics; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Martin Weygandt
- Berlin Center for Advanced Neuroimaging; Charité - Universitätsmedizin Berlin; Berlin Germany
- Bernstein Center for Computational Neuroscience; Berlin Germany
| | - Thomas Christophel
- Berlin Center for Advanced Neuroimaging; Charité - Universitätsmedizin Berlin; Berlin Germany
- Bernstein Center for Computational Neuroscience; Berlin Germany
| | - Eric Barnhill
- Department of Radiology; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Mykola Kadobianskyi
- Berlin Center for Advanced Neuroimaging; Charité - Universitätsmedizin Berlin; Berlin Germany
- Bernstein Center for Computational Neuroscience; Berlin Germany
| | - Jürgen Braun
- Institute of Medical Informatics; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Johannes Bernarding
- Institute of Biometry and Medical Informatics; Otto-von-Guericke University; Magdeburg Germany
| | - Ralf Lützkendorf
- Institute of Biometry and Medical Informatics; Otto-von-Guericke University; Magdeburg Germany
| | - Ingolf Sack
- Department of Radiology; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Stefan Hetzer
- Berlin Center for Advanced Neuroimaging; Charité - Universitätsmedizin Berlin; Berlin Germany
- Bernstein Center for Computational Neuroscience; Berlin Germany
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56
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Kofahl AL, Theilenberg S, Bindl J, Ulucay D, Wild J, Napiletzki S, Schu-Schätter B, Vohlen A, Pintea B, Finsterbusch J, Hattingen E, Urbach C, Maier K. Combining rheology and MRI: Imaging healthy and tumorous brains based on mechanical properties. Magn Reson Med 2016; 78:930-940. [PMID: 27699841 DOI: 10.1002/mrm.26477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 08/22/2016] [Accepted: 09/01/2016] [Indexed: 11/10/2022]
Abstract
PURPOSE It is well known that pathological changes in tissue alter its mechanical properties. This holds also true for brain tissue. In case of the brain, however, obtaining information about these properties is hard due to the surrounding cranial bone. In this paper a novel technique to create an imaging contrast based on the aforementioned properties is presented. METHODS The method is based on an excitation of the brain induced by a short fall. The response of the brain tissue is measured using a motion sensitive MRI sequence. RESULTS The new method is tested by measurements on phantom material as well as on healthy volunteers. In a proof of principle experiment the capability of the approach to identify local alterations in the mechanical properties is shown by means of measurements on meningioma patients. CONCLUSION The presented results show the feasibility of the novel method. Even in this early state of the proposed method, comparisons of measurements on meningioma patients with intraoperative palpation suggest that meningioma tissue responds differently to the excitation depending on their mechanical properties. Magn Reson Med 78:930-940, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Anna-Lisa Kofahl
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
| | | | - Jakob Bindl
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
| | - Deniz Ulucay
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
| | - Judith Wild
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
| | - Sylvia Napiletzki
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
| | - Birgit Schu-Schätter
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
| | - Alexandra Vohlen
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
| | - Bogdan Pintea
- Department of Neurosurgery, University Hospital Bonn, Bonn, Germany
| | - Jürgen Finsterbusch
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Elke Hattingen
- Department of Neuroradiology, University Hospital Bonn, Bonn, Germany
| | - Carsten Urbach
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
| | - Karl Maier
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn, Germany
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Multifrequency magnetic resonance elastography of the brain reveals tissue degeneration in neuromyelitis optica spectrum disorder. Eur Radiol 2016; 27:2206-2215. [DOI: 10.1007/s00330-016-4561-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/01/2016] [Accepted: 08/11/2016] [Indexed: 10/21/2022]
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Hain EG, Klein C, Munder T, Braun J, Riek K, Mueller S, Sack I, Steiner B. Dopaminergic Neurodegeneration in the Mouse Is Associated with Decrease of Viscoelasticity of Substantia Nigra Tissue. PLoS One 2016; 11:e0161179. [PMID: 27526042 PMCID: PMC4985068 DOI: 10.1371/journal.pone.0161179] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 08/01/2016] [Indexed: 11/19/2022] Open
Abstract
The biomechanical properties of brain tissue are altered by histopathological changes due to neurodegenerative diseases like Parkinson's disease (PD). Such alterations can be measured by magnetic resonance elastography (MRE) as a non-invasive technique to determine viscoelastic parameters of the brain. Until now, the correlation between histopathological mechanisms and observed alterations in tissue viscoelasticity in neurodegenerative diseases is still not completely understood. Thus, the objective of this study was to evaluate (1) the validity of MRE to detect viscoelastic changes in small and specific brain regions: the substantia nigra (SN), midbrain and hippocampus in a mouse model of PD, and (2) if the induced dopaminergic neurodegeneration and inflammation in the SN is reflected by local changes in viscoelasticity. Therefore, MRE measurements of the SN, midbrain and hippocampus were performed in adult female mice before and at five time points after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin hydrochloride (MPTP) treatment specifically lesioning dopaminergic neurons in the SN. At each time point, additional mice were utilized for histological analysis of the SN. After treatment cessation, we observed opposed viscoelastic changes in the midbrain, hippocampus and SN with the midbrain showing a gradual rise and the hippocampus a distinct transient increase of viscous and elastic parameters, while viscosity and-to a lesser extent-elasticity in the SN decreased over time. The decrease in viscosity and elasticity in the SN was paralleled by a reduced number of neurons due to the MPTP-induced neurodegeneration. In conclusion, MRE is highly sensitive to detect local viscoelastic changes in specific and even small brain regions. Moreover, we confirmed that neuronal cells likely constitute the backbone of the adult brain mainly accounting for its viscoelasticity. Therefore, MRE could be established as a new potential instrument for clinical evaluation and diagnostics of neurodegenerative diseases.
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Affiliation(s)
- Elisabeth G. Hain
- Department of Neurology, Charité, University Medicine Berlin, Berlin, Germany
| | - Charlotte Klein
- Department of Neurology, Charité, University Medicine Berlin, Berlin, Germany
| | - Tonia Munder
- Department of Neurology, Charité, University Medicine Berlin, Berlin, Germany
| | - Juergen Braun
- Institute for Medical Informatics, Charité, University Medicine Berlin, Berlin, Germany
| | - Kerstin Riek
- Department of Radiology, Charité, University Medicine Berlin, Berlin, Germany
| | | | - Ingolf Sack
- Department of Radiology, Charité, University Medicine Berlin, Berlin, Germany
| | - Barbara Steiner
- Department of Neurology, Charité, University Medicine Berlin, Berlin, Germany
- * E-mail:
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59
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McGrath DM, Ravikumar N, Beltrachini L, Wilkinson ID, Frangi AF, Taylor ZA. Evaluation of wave delivery methodology for brain MRE: Insights from computational simulations. Magn Reson Med 2016; 78:341-356. [PMID: 27416890 DOI: 10.1002/mrm.26333] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Revised: 06/10/2016] [Accepted: 06/17/2016] [Indexed: 01/22/2023]
Abstract
PURPOSE MR elastography (MRE) of the brain is being explored as a biomarker of neurodegenerative disease such as dementia. However, MRE measures for healthy brain have varied widely. Differing wave delivery methodologies may have influenced this, hence finite element-based simulations were performed to explore this possibility. METHODS The natural frequencies of a series of cranial models were calculated, and MRE-associated vibration was simulated for different wave delivery methods at varying frequency, using simple isotropic viscoelastic material models for the brain. Displacement fields and the corresponding brain constitutive properties estimated by standard inversion techniques were compared across delivery methods and frequencies. RESULTS The delivery methods produced widely different MRE displacement fields and inversions. Furthermore, resonances at natural frequencies influenced the displacement patterns. Consequently, some delivery methods led to lower inversion errors than others, and the error on the storage modulus varied by up to 11% between methods. CONCLUSION Wave delivery has a considerable impact on brain MRE reliability. Assuming small variations in brain biomechanics, as recently reported to accompany neurodegenerative disease (e.g., 7% for Alzheimer's disease), the effect of wave delivery is important. Hence, a consensus should be established on a consistent methodology to ensure diagnostic and prognostic consistency. Magn Reson Med 78:341-356, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Deirdre M McGrath
- CISTIB Centre for Computational Imaging & Simulation Technologies in Biomedicine, Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, United Kingdom
- Academic Unit of Radiology, Faculty of Medicine, Dentistry & Health, University of Sheffield, Sheffield, United Kingdom
| | - Nishant Ravikumar
- CISTIB Centre for Computational Imaging & Simulation Technologies in Biomedicine, Department of Mechanical Engineering, University of Sheffield, Sheffield, United Kingdom
| | - Leandro Beltrachini
- CISTIB Centre for Computational Imaging & Simulation Technologies in Biomedicine, Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, United Kingdom
| | - Iain D Wilkinson
- Academic Unit of Radiology, Faculty of Medicine, Dentistry & Health, University of Sheffield, Sheffield, United Kingdom
- INSIGNEO Institute for In Silico Medicine, University of Sheffield, Sheffield, United Kingdom
| | - Alejandro F Frangi
- CISTIB Centre for Computational Imaging & Simulation Technologies in Biomedicine, Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, United Kingdom
- INSIGNEO Institute for In Silico Medicine, University of Sheffield, Sheffield, United Kingdom
| | - Zeike A Taylor
- CISTIB Centre for Computational Imaging & Simulation Technologies in Biomedicine, Department of Mechanical Engineering, University of Sheffield, Sheffield, United Kingdom
- INSIGNEO Institute for In Silico Medicine, University of Sheffield, Sheffield, United Kingdom
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60
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Johnson CL, Schwarb H, D J McGarry M, Anderson AT, Huesmann GR, Sutton BP, Cohen NJ. Viscoelasticity of subcortical gray matter structures. Hum Brain Mapp 2016; 37:4221-4233. [PMID: 27401228 DOI: 10.1002/hbm.23314] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 06/25/2016] [Accepted: 07/05/2016] [Indexed: 12/11/2022] Open
Abstract
Viscoelastic mechanical properties of the brain assessed with magnetic resonance elastography (MRE) are sensitive measures of microstructural tissue health in neurodegenerative conditions. Recent efforts have targeted measurements localized to specific neuroanatomical regions differentially affected in disease. In this work, we present a method for measuring the viscoelasticity in subcortical gray matter (SGM) structures, including the amygdala, hippocampus, caudate, putamen, pallidum, and thalamus. The method is based on incorporating high spatial resolution MRE imaging (1.6 mm isotropic voxels) with a mechanical inversion scheme designed to improve local measures in pre-defined regions (soft prior regularization [SPR]). We find that in 21 healthy, young volunteers SGM structures differ from each other in viscoelasticity, quantified as the shear stiffness and damping ratio, but also differ from the global viscoelasticity of the cerebrum. Through repeated examinations on a single volunteer, we estimate the uncertainty to be between 3 and 7% for each SGM measure. Furthermore, we demonstrate that the use of specific methodological considerations-higher spatial resolution and SPR-both decrease uncertainty and increase sensitivity of the SGM measures. The proposed method allows for reliable MRE measures of SGM viscoelasticity for future studies of neurodegenerative conditions. Hum Brain Mapp 37:4221-4233, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Curtis L Johnson
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801.,Department of Biomedical Engineering, University of Delaware, Newark, Delaware, 19716
| | - Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801
| | - Matthew D J McGarry
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, 03755
| | - Aaron T Anderson
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801.,Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801
| | - Graham R Huesmann
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801.,Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801.,Carle Neuroscience Institute, Carle Foundation Hospital, Urbana, Illinois, 61801
| | - Bradley P Sutton
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801.,Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801
| | - Neal J Cohen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801.,Department of Psychology, University of Illinois at Urbana-Champaign, Champaign, Illinois, 61820
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61
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Anderson AT, Van Houten EEW, McGarry MDJ, Paulsen KD, Holtrop JL, Sutton BP, Georgiadis JG, Johnson CL. Observation of direction-dependent mechanical properties in the human brain with multi-excitation MR elastography. J Mech Behav Biomed Mater 2016; 59:538-546. [PMID: 27032311 PMCID: PMC4860072 DOI: 10.1016/j.jmbbm.2016.03.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 03/01/2016] [Accepted: 03/09/2016] [Indexed: 02/08/2023]
Abstract
Magnetic resonance elastography (MRE) has shown promise in noninvasively capturing changes in mechanical properties of the human brain caused by neurodegenerative conditions. MRE involves vibrating the brain to generate shear waves, imaging those waves with MRI, and solving an inverse problem to determine mechanical properties. Despite the known anisotropic nature of brain tissue, the inverse problem in brain MRE is based on an isotropic mechanical model. In this study, distinct wave patterns are generated in the brain through the use of multiple excitation directions in order to characterize the potential impact of anisotropic tissue mechanics on isotropic inversion methods. Isotropic inversions of two unique displacement fields result in mechanical property maps that vary locally in areas of highly aligned white matter. Investigation of the corpus callosum, corona radiata, and superior longitudinal fasciculus, three highly ordered white matter tracts, revealed differences in estimated properties between excitations of up to 33%. Using diffusion tensor imaging to identify dominant fiber orientation of bundles, relationships between estimated isotropic properties and shear asymmetry are revealed. This study has implications for future isotropic and anisotropic MRE studies of white matter tracts in the human brain.
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Affiliation(s)
- Aaron T Anderson
- Mechanical Science and Engineering Department, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
| | - Elijah E W Van Houten
- Département de génie mécanique, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K2R1; Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA.
| | - Matthew D J McGarry
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA.
| | - Keith D Paulsen
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA; Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA.
| | - Joseph L Holtrop
- Bioengineering Department, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
| | - Bradley P Sutton
- Bioengineering Department, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
| | - John G Georgiadis
- Mechanical Science and Engineering Department, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA; Biomedical Engineering Department, Illinois Institute of Technology, Chicago, Illinois 60616, USA.
| | - Curtis L Johnson
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA; Department of Biomedical Engineering, University of Delaware, Newark, Delaware 19716, USA.
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Schwarb H, Johnson CL, McGarry MDJ, Cohen NJ. Medial temporal lobe viscoelasticity and relational memory performance. Neuroimage 2016; 132:534-541. [PMID: 26931816 PMCID: PMC4970644 DOI: 10.1016/j.neuroimage.2016.02.059] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 01/15/2016] [Accepted: 02/21/2016] [Indexed: 12/13/2022] Open
Abstract
Structural and functional imaging studies have been among converging lines of evidence demonstrating the importance of the hippocampus in successful memory performance. The advent of a novel neuroimaging technique - magnetic resonance elastography (MRE) - now makes it possible for us to investigate the relationship between the microstructural integrity of hippocampal tissue and successful memory processing. Mechanical properties of brain tissue estimated with MRE provide a measure of the integrity of the underlying tissue microstructure and have proven to be sensitive measures of tissue health in neurodegeneration. However, until recently, MRE methods lacked sufficient resolution necessary to accurately examine specific neuroanatomical structures in the brain, and thus could not contribute to examination of specific structure-function relationships. In this study, we took advantage of recent developments in MRE spatial resolution and mechanical inversion techniques to measure the viscoelastic properties of the human hippocampus in vivo, and investigated how these properties reflect hippocampal function. Our data reveal a strong relationship between relative elastic/viscous behavior of the hippocampus and relational memory performance (N=20). This is the first report linking the mechanical properties of brain tissue with functional performance.
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Affiliation(s)
- Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, 405 N. Mathews Ave, Urbana, IL 61081, USA.
| | - Curtis L Johnson
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, 405 N. Mathews Ave, Urbana, IL 61081, USA.
| | - Matthew D J McGarry
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755, USA
| | - Neal J Cohen
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, 405 N. Mathews Ave, Urbana, IL 61081, USA
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63
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Olivero WC, Wszalek T, Wang H, Farahvar A, Rieth SM, Johnson CL. Magnetic Resonance Elastography Demonstrating Low Brain Stiffness in a Patient with Low-Pressure Hydrocephalus: Case Report. Pediatr Neurosurg 2016; 51:257-62. [PMID: 27198914 DOI: 10.1159/000445900] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 04/02/2016] [Indexed: 11/19/2022]
Abstract
The authors describe the case of a 19-year-old female with shunted aqueductal stenosis who presented with low-pressure hydrocephalus that responded to negative pressure drainage. A magnetic resonance elastography scan performed 3 weeks later demonstrated very low brain tissue stiffness (high brain tissue compliance). An analysis of the importance of this finding in understanding this rare condition is discussed.
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Affiliation(s)
- William C Olivero
- Carle Neuroscience Institute, Carle Foundation Hospital, Urbana, Ill., USA
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Fehlner A, Papazoglou S, McGarry MD, Paulsen KD, Guo J, Streitberger KJ, Hirsch S, Braun J, Sack I. Cerebral multifrequency MR elastography by remote excitation of intracranial shear waves. NMR IN BIOMEDICINE 2015; 28:1426-32. [PMID: 26373228 PMCID: PMC4962702 DOI: 10.1002/nbm.3388] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 08/06/2015] [Accepted: 08/07/2015] [Indexed: 05/05/2023]
Abstract
The aim of this study was to introduce remote wave excitation for high-resolution cerebral multifrequency MR elastography (mMRE). mMRE of 25-45-Hz drive frequencies by head rocker stimulation was compared with mMRE by remote wave excitation based on a thorax mat in 12 healthy volunteers. Maps of the magnitude |G*| and phase φ of the complex shear modulus were reconstructed using multifrequency dual elasto-visco (MDEV) inversion. After the scan, the subjects and three operators assessed the comfort and convenience of cerebral mMRE using two methods of stimulating the brain. Images were acquired in a coronal view in order to identify anatomical regions along the spinothalamic pathway. In mMRE by remote actuation, all subjects and operators appreciated an increased comfort and simplified procedural set-up. The resulting strain amplitudes in the brain were sufficiently large to analyze using MDEV inversion, and yielded high-resolution viscoelasticity maps which revealed specific anatomical details of brain mechanical properties: |G*| was lowest in the pons (0.97 ± 0.08 kPa) and decreased within the corticospinal tract in the caudal-cranial direction from the crus cerebri (1.64 ± 0.26 kPa) to the capsula interna (1.29 ± 0.14 kPa). By avoiding onerous mechanical stimulation of the head, remote excitation of intracranial shear waves can be used to measure viscoelastic parameters of the brain with high spatial resolution. Therewith, the new mMRE method is suitable for neuroradiological examinations in the clinic.
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Affiliation(s)
- Andreas Fehlner
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | | | - Keith D Paulsen
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Jing Guo
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Sebastian Hirsch
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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65
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Dittmann F, Hirsch S, Tzschätzsch H, Guo J, Braun J, Sack I. In vivo wideband multifrequency MR elastography of the human brain and liver. Magn Reson Med 2015; 76:1116-26. [DOI: 10.1002/mrm.26006] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 08/25/2015] [Accepted: 09/12/2015] [Indexed: 01/19/2023]
Affiliation(s)
- Florian Dittmann
- Department of Radiology; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Sebastian Hirsch
- Institute of Medical Informatics; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Heiko Tzschätzsch
- Department of Radiology; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Jing Guo
- Department of Radiology; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Jürgen Braun
- Institute of Medical Informatics; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Ingolf Sack
- Department of Radiology; Charité - Universitätsmedizin Berlin; Berlin Germany
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66
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McGrath DM, Ravikumar N, Wilkinson ID, Frangi AF, Taylor ZA. Magnetic resonance elastography of the brain: An in silico study to determine the influence of cranial anatomy. Magn Reson Med 2015; 76:645-62. [PMID: 26417988 DOI: 10.1002/mrm.25881] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 07/11/2015] [Accepted: 07/19/2015] [Indexed: 12/15/2022]
Abstract
PURPOSE Magnetic resonance elastography (MRE) of the brain has demonstrated potential as a biomarker of neurodegenerative disease such as dementia but requires further evaluation. Cranial anatomical features such as the falx cerebri and tentorium cerebelli membranes may influence MRE measurements through wave reflection and interference and tissue heterogeneity at their boundaries. We sought to determine the influence of these effects via simulation. METHODS MRE-associated mechanical stimulation of the brain was simulated using steady state harmonic finite element analysis. Simulations of geometrical models and anthropomorphic brain models derived from anatomical MRI data of healthy individuals were compared. Constitutive parameters were taken from MRE measurements for healthy brain. Viscoelastic moduli were reconstructed from the simulated displacement fields and compared with ground truth. RESULTS Interference patterns from reflections and heterogeneity resulted in artifacts in the reconstructions of viscoelastic moduli. Artifacts typically occurred in the vicinity of boundaries between different tissues within the cranium, with a magnitude of 10%-20%. CONCLUSION Given that MRE studies for neurodegenerative disease have reported only marginal variations in brain elasticity between controls and patients (e.g., 7% for Alzheimer's disease), the predicted errors are a potential confound to the development of MRE as a biomarker of dementia and other neurodegenerative diseases. Magn Reson Med 76:645-662, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Deirdre M McGrath
- CISTIB Centre for Computational Imaging & Simulation Technologies in Biomedicine, Department of Electronic and Electrical Engineering, The University of Sheffield, Sheffield, UK.,Academic Unit of Radiology, Faculty of Medicine, Dentistry & Health, The University of Sheffield, Sheffield, UK
| | - Nishant Ravikumar
- CISTIB Centre for Computational Imaging & Simulation Technologies in Biomedicine, Department of Mechanical Engineering, The University of Sheffield, Sheffield, UK
| | - Iain D Wilkinson
- Academic Unit of Radiology, Faculty of Medicine, Dentistry & Health, The University of Sheffield, Sheffield, UK.,INSIGNEO Institute for In Silico Medicine, The University of Sheffield, Sheffield, UK
| | - Alejandro F Frangi
- CISTIB Centre for Computational Imaging & Simulation Technologies in Biomedicine, Department of Electronic and Electrical Engineering, The University of Sheffield, Sheffield, UK.,INSIGNEO Institute for In Silico Medicine, The University of Sheffield, Sheffield, UK
| | - Zeike A Taylor
- CISTIB Centre for Computational Imaging & Simulation Technologies in Biomedicine, Department of Mechanical Engineering, The University of Sheffield, Sheffield, UK.,INSIGNEO Institute for In Silico Medicine, The University of Sheffield, Sheffield, UK
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67
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Millward JM, Guo J, Berndt D, Braun J, Sack I, Infante-Duarte C. Tissue structure and inflammatory processes shape viscoelastic properties of the mouse brain. NMR IN BIOMEDICINE 2015; 28:831-839. [PMID: 25963743 DOI: 10.1002/nbm.3319] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 04/02/2015] [Accepted: 04/07/2015] [Indexed: 06/04/2023]
Abstract
Magnetic resonance elastography (MRE) is an imaging method that reveals the mechanical properties of tissue, modelled as a combination of " viscosity" and " elasticity" . We recently showed reduced brain viscoelasticity in multiple sclerosis (MS) patients compared with healthy controls, and in the relapsing-remitting disease model experimental autoimmune encephalomyelitis (EAE). However, the mechanisms by which these intrinsic tissue properties become altered remain unclear. This study investigates whether distinct regions in the mouse brain differ in their native viscoelastic properties, and how these properties are affected during chronic EAE in C57Bl/6 mice and in mice lacking the cytokine interferon-gamma. IFN-γ(-/-) mice exhibit a more severe EAE phenotype, with amplified inflammation in the cerebellum and brain stem. Brain scans were performed in the sagittal plane using a 7 T animal MRI scanner, and the anterior (cerebral) and posterior (cerebellar) regions analyzed separately. MRE investigations were accompanied by contrast-enhanced MRI scans, and by histopathology and gene expression analysis ex vivo. Compared with the cerebrum, the cerebellum in healthy mice has a lower viscoelasticity, i.e. it is intrinsically " softer" . This was seen both in the wild-type mice and the IFNγ(-/-) mice. During chronic EAE, C57Bl/6 mice did not show altered brain viscoelasticity. However, as expected, the IFNγ(-/-) mice showed a more severe EAE phenotype, and these mice did show altered brain elasticity during the course of disease. The magnitude of the elasticity reduction correlated with F4/80 gene expression, a marker for macrophages/microglia in inflamed central nervous system tissue. Together these results demonstrate that MRE is sensitive enough to discriminate between viscoelastic properties in distinct anatomical structures in the mouse brain, and to confirm a further relationship between cellular inflammation and mechanical alterations of the brain. This study underscores the utility of MRE to monitor pathological tissue alterations in vivo.
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Affiliation(s)
- Jason M Millward
- Institute for Medical Immunology, Charité - Universitätmedizin Berlin, Germany
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Jing Guo
- Department of Radiology, Charité - Universitätsmedizin Berlin, Germany
| | - Dominique Berndt
- Institute for Medical Immunology, Charité - Universitätmedizin Berlin, Germany
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Jürgen Braun
- Department of Radiology, Charité - Universitätsmedizin Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Germany
| | - Carmen Infante-Duarte
- Institute for Medical Immunology, Charité - Universitätmedizin Berlin, Germany
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany
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68
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Recent imaging advances in neurology. J Neurol 2015; 262:2182-94. [PMID: 25808503 DOI: 10.1007/s00415-015-7711-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 03/13/2015] [Accepted: 03/14/2015] [Indexed: 01/08/2023]
Abstract
Over the recent years, the application of neuroimaging techniques such as magnetic resonance imaging (MRI) and positron emission tomography (PET) has considerably advanced the understanding of complex neurological disorders. PET is a powerful molecular imaging tool, which investigates the distribution and binding of radiochemicals attached to biologically relevant molecules; as such, this technique is able to give information on biochemistry and metabolism of the brain in health and disease. MRI uses high intensity magnetic fields and radiofrequency pulses to provide structural and functional information on tissues and organs in intact or diseased individuals, including the evaluation of white matter integrity, grey matter thickness and brain perfusion. The aim of this article is to review the most recent advances in neuroimaging research in common neurological disorders such as movement disorders, dementia, epilepsy, traumatic brain injury and multiple sclerosis, and to evaluate their contribution in the diagnosis and management of patients.
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69
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Ipek-Ugay S, Drießle T, Ledwig M, Guo J, Hirsch S, Sack I, Braun J. Tabletop magnetic resonance elastography for the measurement of viscoelastic parameters of small tissue samples. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 251:13-18. [PMID: 25554945 DOI: 10.1016/j.jmr.2014.11.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 11/18/2014] [Accepted: 11/19/2014] [Indexed: 06/04/2023]
Abstract
We demonstrate the feasibility of low-cost tabletop MR elastography (MRE) for quantifying the complex shear modulus G(∗) of small soft biological tissue samples as provided by pathologists. The MRE system was developed based on a tabletop MRI scanner equipped with a 0.5 T permanent magnet and a tissue sample holder mounted to a loudspeaker. A spin echo sequence was enhanced with motion-encoding gradients of 250 mT/m amplitude synchronized to acoustic vibration frequencies. Shear wave images suitable for elastography were acquired between vibration frequencies of 0.5 and 1 kHz in agarose, ultrasound gel, porcine liver, porcine skeletal muscle, and bovine heart with a spatial resolution of 234 μm pixel edge length. The measured frequency dependence of G(∗) agreed well with previous work based on high-field MR systems. The ratio between loss and storage moduli was highest in liver and ultrasound gel, followed by muscle tissue and agarose gel while ultrasound gel and liver showed similarly low storage moduli compared to the other samples. The shear wave to noise ratio is an important imaging criteria for MRE and was about 4.2 times lower for the preliminary setup of the 0.5 T tabletop system compared to a 7 T animal scanner. In the future, the new tabletop MRE system may serve as a low cost device for preclinical research on the correlation of viscoelastic parameters with histopathology of biological samples.
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Affiliation(s)
- Selcan Ipek-Ugay
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | | | - Jing Guo
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Hirsch
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany.
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70
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Streitberger KJ, Reiss-Zimmermann M, Freimann FB, Bayerl S, Guo J, Arlt F, Wuerfel J, Braun J, Hoffmann KT, Sack I. High-resolution mechanical imaging of glioblastoma by multifrequency magnetic resonance elastography. PLoS One 2014; 9:e110588. [PMID: 25338072 PMCID: PMC4206430 DOI: 10.1371/journal.pone.0110588] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 09/17/2014] [Indexed: 12/14/2022] Open
Abstract
Objective To generate high-resolution maps of the viscoelastic properties of human brain parenchyma for presurgical quantitative assessment in glioblastoma (GB). Methods Twenty-two GB patients underwent routine presurgical work-up supplemented by additional multifrequency magnetic resonance elastography. Two three-dimensional viscoelastic parameter maps, magnitude |G*|, and phase angle φ of the complex shear modulus were reconstructed by inversion of full wave field data in 2-mm isotropic resolution at seven harmonic drive frequencies ranging from 30 to 60 Hz. Results Mechanical brain maps confirmed that GB are composed of stiff and soft compartments, resulting in high intratumor heterogeneity. GB could be easily differentiated from healthy reference tissue by their reduced viscous behavior quantified by φ (0.37±0.08 vs. 0.58±0.07). |G*|, which in solids more relates to the material's stiffness, was significantly reduced in GB with a mean value of 1.32±0.26 kPa compared to 1.54±0.27 kPa in healthy tissue (P = 0.001). However, some GB (5 of 22) showed increased stiffness. Conclusion GB are generally less viscous and softer than healthy brain parenchyma. Unrelated to the morphology-based contrast of standard magnetic resonance imaging, elastography provides an entirely new neuroradiological marker and contrast related to the biomechanical properties of tumors.
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Affiliation(s)
| | | | | | - Simon Bayerl
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jing Guo
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Felix Arlt
- Department of Neurosurgery, Universitätsmedizin Leipzig, Leipzig, Germany
| | - Jens Wuerfel
- Institute of Neuroradiology, Universitätsmedizin Göttingen, Göttingen, Germany
- NeuroCure, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
- * E-mail:
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71
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Reiss-Zimmermann M, Streitberger KJ, Sack I, Braun J, Arlt F, Fritzsch D, Hoffmann KT. High Resolution Imaging of Viscoelastic Properties of Intracranial Tumours by Multi-Frequency Magnetic Resonance Elastography. Clin Neuroradiol 2014; 25:371-8. [PMID: 24916129 DOI: 10.1007/s00062-014-0311-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 04/29/2014] [Indexed: 12/24/2022]
Abstract
PURPOSE In recent years Magnetic Resonance Elastography (MRE) emerged into a clinically applicable imaging technique. It has been shown that MRE is capable of measuring global changes of the viscoelastic properties of cerebral tissue. The purpose of our study was to evaluate a spatially resolved three-dimensional multi-frequent MRE (3DMMRE) for assessment of the viscoelastic properties of intracranial tumours. METHODS A total of 27 patients (63 ± 13 years) were included. All examinations were performed on a 3.0 T scanner, using a modified phase-contrast echo planar imaging sequence. We used 7 vibration frequencies in the low acoustic range with a temporal resolution of 8 dynamics per wave cycle. Post-processing included multi-frequency dual elasto-visco (MDEV) inversion to generate high-resolution maps of the magnitude |G*| and the phase angle φ of the complex valued shear modulus. RESULTS The tumour entities included in this study were: glioblastoma (n = 11), anaplastic astrocytoma (n = 3), meningioma (n = 7), cerebral metastasis (n = 5) and intracerebral abscess formation (n = 1). Primary brain tumours and cerebral metastases were not distinguishable in terms of |G*| and φ. Glioblastoma presented the largest range of |G*| values and a trend was delineable that glioblastoma were slightly softer than WHO grade III tumours. In terms of φ, meningiomas were clearly distinguishable from all other entities. CONCLUSIONS In this pilot study, while analysing the viscoelastic constants of various intracranial tumour entities with an improved spatial resolution, it was possible to characterize intracranial tumours by their mechanical properties. We were able to clearly delineate meningiomas from intraaxial tumours, while for the latter group an overlap remains in viscoelastic terms.
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Affiliation(s)
- M Reiss-Zimmermann
- Department of Neuroradiology, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany.
| | - K-J Streitberger
- Department of Radiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - I Sack
- Department of Radiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - J Braun
- Department of Radiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - F Arlt
- Department of Neurosurgery, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany
| | - D Fritzsch
- Department of Neuroradiology, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany
| | - K-T Hoffmann
- Department of Neuroradiology, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany
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