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Luo Y, Sheng H, Zhou Y, Min L, Tu C, Luo Y. Modular Hemipelvic Prosthesis Preserves Normal Biomechanics and Showed Good Compatibility: A Finite Element Analysis. J Funct Biomater 2024; 15:276. [PMID: 39330251 PMCID: PMC11433228 DOI: 10.3390/jfb15090276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2024] [Revised: 09/13/2024] [Accepted: 09/19/2024] [Indexed: 09/28/2024] Open
Abstract
This study aimed to evaluate the biomechanical compatibility of a modular hemipelvic prosthesis by comparing stress distributions between an implanted pelvis and a healthy pelvis. Finite element analysis was used to simulate bilateral standing loads on both models, analyzing critical regions such as the sacroiliac joints, iliac crest, acetabulum, and prosthesis connection points. Six models with varied displacements of the hip joint rotational center were also introduced to assess the impact of deviations on stress distribution. The implanted pelvis had a stress distribution closely matching that of the intact pelvis, indicating that the prosthesis design maintained the biomechanical integrity of the pelvis. Stress patterns in displacement models with deviations of less than 10 mm were similar to the standard model, with only minor changes in stress magnitude. However, backward, upward, and inward deviations resulted in stress concentrations, particularly in the prosthesis connection points, increasing the likelihood of mechanical failure. The modular hemipelvic prosthesis demonstrated good biomechanical compatibility with minimal impact on pelvic stress distribution, even with moderate deviations in the hip joint's rotational center; outward, forward, and downward displacements are preferable to minimize stress concentration and prevent implant failure in cases where minor deviations in the rotational center are unavoidable during surgery.
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Affiliation(s)
- Yuanrui Luo
- Department of Orthopedics, Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Hongtao Sheng
- Department of Orthopedics, Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu 610041, China
- Model Worker and Craftsman Talent Innovation Workshop of Sichuan Province, No. 37 Guoxue Road, Chengdu 610041, China
| | - Yong Zhou
- Department of Orthopedics, Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu 610041, China
- Model Worker and Craftsman Talent Innovation Workshop of Sichuan Province, No. 37 Guoxue Road, Chengdu 610041, China
| | - Li Min
- Department of Orthopedics, Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu 610041, China
- Model Worker and Craftsman Talent Innovation Workshop of Sichuan Province, No. 37 Guoxue Road, Chengdu 610041, China
| | - Chongqi Tu
- Department of Orthopedics, Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu 610041, China
- Model Worker and Craftsman Talent Innovation Workshop of Sichuan Province, No. 37 Guoxue Road, Chengdu 610041, China
| | - Yi Luo
- Department of Orthopedics, Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu 610041, China
- Model Worker and Craftsman Talent Innovation Workshop of Sichuan Province, No. 37 Guoxue Road, Chengdu 610041, China
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Marupudi S, Cao Q, Samala R, Petrick N. Characterization of mechanical stiffness using additive manufacturing and finite element analysis: potential tool for bone health assessment. 3D Print Med 2023; 9:32. [PMID: 37978094 PMCID: PMC10656885 DOI: 10.1186/s41205-023-00197-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 11/07/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Bone health and fracture risk are known to be correlated with stiffness. Both micro-finite element analysis (μFEA) and mechanical testing of additive manufactured phantoms are useful approaches for estimating mechanical properties of trabecular bone-like structures. However, it is unclear if measurements from the two approaches are consistent. The purpose of this work is to evaluate the agreement between stiffness measurements obtained from mechanical testing of additive manufactured trabecular bone phantoms and μFEA modeling. Agreement between the two methods would suggest 3D printing is a viable method for validation of μFEA modeling. METHODS A set of 20 lumbar vertebrae regions of interests were segmented and the corresponding trabecular bone phantoms were produced using selective laser sintering. The phantoms were mechanically tested in uniaxial compression to derive their stiffness values. The stiffness values were also derived from in silico simulation, where linear elastic μFEA was applied to simulate the same compression and boundary conditions. Bland-Altman analysis was used to evaluate agreement between the mechanical testing and μFEA simulation values. Additionally, we evaluated the fidelity of the 3D printed phantoms as well as the repeatability of the 3D printing and mechanical testing process. RESULTS We observed good agreement between the mechanically tested stiffness and μFEA stiffness, with R2 of 0.84 and normalized root mean square deviation of 8.1%. We demonstrate that the overall trabecular bone structures are printed in high fidelity (Dice score of 0.97 (95% CI, [0.96,0.98]) and that mechanical testing is repeatable (coefficient of variation less than 5% for stiffness values from testing of duplicated phantoms). However, we noticed some defects in the resin microstructure of the 3D printed phantoms, which may account for the discrepancy between the stiffness values from simulation and mechanical testing. CONCLUSION Overall, the level of agreement achieved between the mechanical stiffness and μFEA indicates that our μFEA methods may be acceptable for assessing bone mechanics of complex trabecular structures as part of an analysis of overall bone health.
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Affiliation(s)
- Sriharsha Marupudi
- Division of Imaging, Diagnostics, and Software Reliability, Office of Science and Engineering Labs, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Qian Cao
- Division of Imaging, Diagnostics, and Software Reliability, Office of Science and Engineering Labs, U.S. Food and Drug Administration, Silver Spring, MD, USA.
| | - Ravi Samala
- Division of Imaging, Diagnostics, and Software Reliability, Office of Science and Engineering Labs, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Nicholas Petrick
- Division of Imaging, Diagnostics, and Software Reliability, Office of Science and Engineering Labs, U.S. Food and Drug Administration, Silver Spring, MD, USA
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Guha I, Zhang X, Nadeem SA, Levy SM, Saha PK. Continuum finite element analysis generalizes in vivotrabecular bone microstructural strength measures between two CT scanners with different image resolution. Biomed Phys Eng Express 2023; 9:025012. [PMID: 36763987 PMCID: PMC9945196 DOI: 10.1088/2057-1976/acbb0a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 02/10/2023] [Indexed: 02/12/2023]
Abstract
Fragility of trabecular bone (Tb) microstructure is increased in osteoporosis, which is associated with rapid bone loss and enhanced fracture-risk. Accurate assessment of Tb strength usingin vivoimaging available in clinical settings will be significant for management of osteoporosis and understanding its pathogenesis. Emerging CT technology, featured with high image resolution, fast scan-speed, and wide clinical access, is a promising alternative forin vivoTb imaging. However, variation in image resolution among different CT scanners pose a major hurdle in CT-based bone studies. This paper presents nonlinear continuum finite element (FE) methods for computation of Tb strength fromin vivoCT imaging and evaluates their generalizability between two scanners with different image resolution. Continuum FE-based measures of Tb strength under different loading conditions were found to be highly reproducible (ICC ≥ 0.93) using ankle images of twenty healthy volunteers acquired on low- and high-resolution CT scanners 44.6 ± 2.7 days apart. FE stress propagation was mostly confined to Tb micro-network (2.3 ± 1.7 MPa) with nominal leakages over the marrow space (0.4 ± 0.5 MPa) complying with the fundamental principle of mechanics atin vivoimaging. In summary, nonlinear continuum FE-based Tb strength measures are reproducible among different CT scanners and suitable for multi-site longitudinal human studies.
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Affiliation(s)
- Indranil Guha
- Department of Electrical and Computer Engineering, College of Engineering, University of Iowa, Iowa City, IA, United States of America
| | - Xiaoliu Zhang
- Department of Electrical and Computer Engineering, College of Engineering, University of Iowa, Iowa City, IA, United States of America
| | - Syed Ahmed Nadeem
- Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States of America
| | - Steven M Levy
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA, United States of America,
Department of Preventive and Community Dentistry, College of Dentistry, University of Iowa, Iowa City, IA, United States of America
| | - Punam K Saha
- Department of Electrical and Computer Engineering, College of Engineering, University of Iowa, Iowa City, IA, United States of America,
Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States of America
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Carlsson J, Braesch-Andersen A, Ferguson SJ, Isaksson P. Fracture in porous bone analysed with a numerical phase-field dynamical model. J Mech Behav Biomed Mater 2023; 139:105659. [PMID: 36638634 DOI: 10.1016/j.jmbbm.2023.105659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/13/2022] [Accepted: 01/04/2023] [Indexed: 01/07/2023]
Abstract
A dynamic phase-field fracture finite element model is applied to discretized high-resolution three-dimensional computed tomography images of human trabecular bone to analyse rapid bone fracture. The model is contrasted to quasi-static experimental results and a quasi-static phase-field finite element model. The experiment revealed complex stepwise crack evolution with multiple crack fronts, and crack arrests, as the global tensile displacement load was incrementally increased. The quasi-static phase-field fracture model captures the fractures in the experiment reasonably well, and the dynamic model converges towards the quasi-static model when mechanically loaded at low rates. At higher load rates, i.e., at larger impulses, inertia effects significantly contribute to an increased initial global stiffness, higher peak forces and a larger number of cracks spread over a larger volume. Since the fracture process clearly is different at large impulses compared to small impulses, it is concluded that dynamic fracture models are necessary when simulating rapid bone fracture.
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Affiliation(s)
- Jenny Carlsson
- Solid Mechanics, Department of Materials Science and Engineering, Uppsala University, Sweden; Now at Cambridge University Engineering Department, Trumpington St., Cambridge, UK
| | - Anna Braesch-Andersen
- Solid Mechanics, Department of Materials Science and Engineering, Uppsala University, Sweden
| | | | - Per Isaksson
- Solid Mechanics, Department of Materials Science and Engineering, Uppsala University, Sweden.
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Clausing RJ, Stiller A, Kuhn F, Fonseca Ulloa CA, Fölsch C, Kampschulte M, Krombach GA, Rickert M, Jahnke A. Measuring Young's modulus of single trabeculae in cancellous bone using a two-point bending test. Clin Biomech (Bristol, Avon) 2023; 102:105875. [PMID: 36634601 DOI: 10.1016/j.clinbiomech.2023.105875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 12/30/2022] [Accepted: 01/04/2023] [Indexed: 01/07/2023]
Abstract
BACKROUND Surgical treatment of proximal humeral fractures poses a major challenge, especially in osteoporotic bone. At present, there appears to exist neither a suitable model for research to optimize the osteosynthesis processes nor are the structural data available which are required for developing such a model. Therefore, the aim of this study is to determine the microscopic morphology and Young's modulus of cancellous bone from human humeral heads considering osteoporotic changes. METHODS Cylindrical samples were taken from ten fresh-frozen human humeral heads and structural analysis was done with μCT. Ten rod-like trabeculae were prepared from five of the humeral heads each which were measured and tested mechanically. For this purpose, the trabeculae were fixed on a slide and rotated axially under a stereo microscope. The sample cross-section and the depending moment of inertia were extracted from the image data. The samples were then loaded in a 2-point bending test and Young's moduli of the samples were determined. RESULTS It could be shown that with increasing age of the donor, ossified portion of the cancellous bone decreased (p < 0.05). The average degree of mineralization of the bone was 1.24 (±0.06) g/mm3, which decreased with increasing age (p < 0.05). The determined Young's modulus averaged 1.33 (±1.76) GPa. INTERPRETATION The verified structural parameter showed osteoporotic changes in the examined bone. This study for the first time determined Young's modulus of single trabeculae of cancellous bone of osteoporotically altered human humeral heads. Implementing the non-destructive sample measurement before exposure resulted in a methodical improvement.
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Affiliation(s)
- Rasmus Johannes Clausing
- Laboratory of Biomechanics, Department of Orthopaedics and Orthopaedic Surgery, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany
| | - Alexander Stiller
- Laboratory of Biomechanics, Department of Orthopaedics and Orthopaedic Surgery, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany
| | - Florian Kuhn
- Laboratory of Biomechanics, Department of Orthopaedics and Orthopaedic Surgery, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany
| | - Carlos Alfonso Fonseca Ulloa
- Laboratory of Biomechanics, Department of Orthopaedics and Orthopaedic Surgery, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany
| | - Christian Fölsch
- Laboratory of Biomechanics, Department of Orthopaedics and Orthopaedic Surgery, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany; Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstraße 33, 35392 Giessen, Germany
| | - Marian Kampschulte
- Department of Diagnostic and Interventional Radiology, University Hospital Giessen and Marburg (UKGM), Klinikstraße 33, 35392 Giessen, Germany
| | - Gabriele A Krombach
- Department of Diagnostic and Interventional Radiology, University Hospital Giessen and Marburg (UKGM), Klinikstraße 33, 35392 Giessen, Germany
| | - Markus Rickert
- Laboratory of Biomechanics, Department of Orthopaedics and Orthopaedic Surgery, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany; Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstraße 33, 35392 Giessen, Germany
| | - Alexander Jahnke
- Laboratory of Biomechanics, Department of Orthopaedics and Orthopaedic Surgery, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany.
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Braesch-Andersen A, Wu D, Ferguson SJ, Persson C, Isaksson P. Application of phase-field fracture theories and digital volume correlation to synchrotron X-ray monitored fractures in human trabecular bone: A case study. J Mech Behav Biomed Mater 2022; 135:105446. [PMID: 36154992 DOI: 10.1016/j.jmbbm.2022.105446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 08/10/2022] [Accepted: 09/01/2022] [Indexed: 11/25/2022]
Abstract
Fracture processes of trabecular bone have been studied using various approaches over the years. However, reliable methods to analyse fracture at the single trabecula level are limited. In this study, a digital volume correlation (DVC) and a phase-field fracture model are applied and contrasted for human trabecular bone to analyse its failure under global compression at high resolution. A human trabecular bone sample was fractured in situ under synchrotron-based X-ray micro computed tomography (CT). Reconstructed CT data was then used in DVC algorithms to obtain high-resolution displacement fields in the bone at different load steps. A high-resolution specimen-specific structural mesh was discretized from the CT data and used for the phase-field simulation of the fracturing bone. The DVC analysis showed opening mode cracks as well as shear mode cracks. Strains in cracked regions were analysed. The load distribution in the trabecular structure resulted in two completely separated fracture regions in the sample body. A phenomenon that was also captured in the phase-field model. The results encourage us to believe improvements in boundary conditions and material models are worthwhile pursuing. Findings in this study support further development of a phase-field method to analyse fracture in samples with complex morphology, such as trabecular bone, and the capacity of DVC to quantify strains and slowly growing stable fractures during step-wise loading of trabecular bone.
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Affiliation(s)
| | - Dan Wu
- Department of Materials Science and Engineering, Uppsala University, Sweden
| | | | - Cecilia Persson
- Department of Materials Science and Engineering, Uppsala University, Sweden
| | - Per Isaksson
- Department of Materials Science and Engineering, Uppsala University, Sweden.
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Guha I, Zhang X, Rajapakse CS, Chang G, Saha PK. Finite element analysis of trabecular bone microstructure using CT imaging and continuum mechanical modelling. Med Phys 2022; 49:3886-3899. [PMID: 35319784 PMCID: PMC9325403 DOI: 10.1002/mp.15629] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 11/16/2022] Open
Abstract
Purpose Osteoporosis is a bone disease associated with enhanced bone loss, microstructural degeneration, and fracture‐risk. Finite element (FE) modeling is used to estimate trabecular bone (Tb) modulus from high‐resolution three‐dimensional (3‐D) imaging modalities including micro‐computed tomography (CT), magnetic resonance imaging (MRI), and high‐resolution peripheral quantitative CT (HR‐pQCT). This paper validates an application of voxel‐based continuum finite element analysis (FEA) to predict Tb modulus from clinical CT imaging under a condition similar to in vivo imaging by comparing with measures derived by micro‐CT and experimental approaches. Method Voxel‐based continuum FEA methods for CT imaging were implemented using linear and nonlinear models and applied on distal tibial scans under a condition similar to in vivo imaging. First, tibial axis in a CT scan was aligned with the coordinate z‐axis at 150 μm isotropic voxels. FEA was applied on an upright cylindrical volume of interests (VOI) with its axis coinciding with the tibial bone axis. Voxel volume, edge, and vertex elements and their connectivity were defined as per the isotropic image grid. A calibration phantom was used to calibrate CT numbers in Hounsfield unit to bone mineral density (BMD) values, which was then converted into calcium hydroxyapatite (CHA) density. Mechanical properties at each voxel volume element was defined using its ash‐density defined on CT‐derived CHA density. For FEA, the bottom surface of the cylindrical VOI was fixed and a constant displacement was applied along the z‐direction at each vertex element on the top surface to simulate a physical axial compressive loading condition. Finally, a Poisson's ratio of 0.3 was applied, and Tb modulus (MPa) was computed as the ratio of average von Mises stress (MPa) of volume elements on the top surface and the applied displacement. FEA parameters including mesh element size, substep number, and different tolerance values were optimized. Results CT‐derived Tb modulus values using continuum FEA showed high linear correlation with the micro‐CT‐derived reference values (r ∈ [0.87 0.90]) as well as experimentally measured values (r ∈ [0.80 0.87]). Linear correlation of computed modulus with their reference values using continuum FEA with linear modeling was comparable with that obtained by nonlinear modeling. Nonlinear continuum FEA‐based modulus values (mean of 1087.2 MPa) showed greater difference from their reference values (mean of 1498.9 MPa using micro‐CT‐based FEA) as compared with linear continuum methods. High repeat CT scan reproducibility (intra‐class correlation [ICC] = 0.98) was observed for computed modulus values using both linear and nonlinear continuum FEA. It was observed that high stress regions coincide with Tb microstructure as fuzzily characterized by BMD values. Distributions of von Mises stress over Tb microstructure and marrow regions were significantly different (p < 10–8). Conclusion Voxel‐based continuum FEA offers surrogate measures of Tb modulus from CT imaging under a condition similar to in vivo imaging that alleviates the need for segmentation of Tb and marrow regions, while accounting for bone distribution at the microstructural level. This relaxation of binary segmentation will extend the scope of FEA application to assess mechanical properties of bone microstructure at relatively low‐resolution imaging.
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Affiliation(s)
- Indranil Guha
- Department of Electrical and Computer Engineering, College of Engineering, University of Iowa, Iowa City, IA, 52242, USA
| | - Xiaoliu Zhang
- Department of Electrical and Computer Engineering, College of Engineering, University of Iowa, Iowa City, IA, 52242, USA
| | - Chamith S Rajapakse
- Departments of Radiology and Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Gregory Chang
- Department of Radiology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Punam K Saha
- Department of Electrical and Computer Engineering, College of Engineering, University of Iowa, Iowa City, IA, 52242, USA.,Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
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Torres FFE, Jacobs R, EzEldeen M, de Faria-Vasconcelos K, Guerreiro-Tanomaru JM, Dos Santos BC, Tanomaru-Filho M. How image-processing parameters can influence the assessment of dental materials using micro-CT. Imaging Sci Dent 2020; 50:161-168. [PMID: 32601591 PMCID: PMC7314609 DOI: 10.5624/isd.2020.50.2.161] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/14/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022] Open
Abstract
Purpose The aim of this study was to evaluate the influence of voxel size and different post-processing algorithms on the analysis of dental materials using micro-computed tomography (micro-CT). Materials and Methods Root-end cavities were prepared in extracted maxillary premolars, filled with mineral trioxide aggregate (MTA), Biodentine, and Intermediate Restorative Material (IRM), and scanned using micro-CT. The volume and porosity of materials were evaluated and compared using voxel sizes of 5, 10, and 20 µm, as well as different software tools (post-processing algorithms). The CTAn or MeVisLab/Materialise 3-matic software package was used to perform volume and morphological analyses, and the CTAn or MeVisLab/Amira software was used to evaluate porosity. Data were analyzed using 1-way ANOVA and the Tukey test (P<0.05). Results Using MeVisLab/Materialise 3-matic, a consistent tendency was observed for volume to increase at larger voxel sizes. CTAn showed higher volumes for MTA and IRM at 20 µm. Using CTAn, porosity values decreased as voxel size increased, with statistically significant differences for all materials. MeVisLab/Amira showed a difference for MTA and IRM at 5 µm, and for Biodentine at 20 µm. Significant differences in volume and porosity were observed in all software packages for Biodentine across all voxel sizes. Conclusion Some differences in volume and porosity were found according to voxel size, image-processing software, and the radiopacity of the material. Consistent protocols are needed for research evaluating dental materials.
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Affiliation(s)
| | - Reinhilde Jacobs
- OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, KU Leuven and Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium.,Department of Dental Medicine, Karolinska Institute, Stockholm, Sweden
| | - Mostafa EzEldeen
- OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, KU Leuven and Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Karla de Faria-Vasconcelos
- OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, KU Leuven and Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium
| | | | | | - Mário Tanomaru-Filho
- Department of Restorative Dentistry, São Paulo State University (UNESP), School of Dentistry, Araraquara, SP, Brazil
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Schwarzenberg P, Dailey HL. Elementwise material assignment in reconstructed or transformed patient-specific FEA models developed from CT scans. Comput Methods Biomech Biomed Engin 2020; 23:92-102. [PMID: 31809579 DOI: 10.1080/10255842.2019.1699545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In patient-specific finite element modeling, elementwise material assignment calculates local mechanical properties from the underlying CT data. If meshes must be transformed, for example to reconstruct broken bones, this elementwise material mapping is not possible using commercial software. Accordingly, we developed an algorithm to transform and reconstruct CT scans and fill gaps at discontinuities. Virtual mechanical testing showed that iterative reconstruction retains material heterogeneity with minimal strain artifacts and achieves whole-bone mechanics clinically equivalent (within 5%) to homogeneous models. This approach may expand the range of clinical CT scans that are viable for virtual biomechanics by allowing defect repair.
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Affiliation(s)
- Peter Schwarzenberg
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA, USA
| | - Hannah L Dailey
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA, USA
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Yamada S, Chiba K, Okazaki N, Era M, Nishino Y, Yokota K, Yonekura A, Tomita M, Tsurumoto T, Osaki M. Correlation between vertebral bone microstructure and estimated strength in elderly women: An ex-vivo HR-pQCT study of cadaveric spine. Bone 2019; 120:459-464. [PMID: 30553854 DOI: 10.1016/j.bone.2018.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 12/03/2018] [Accepted: 12/07/2018] [Indexed: 02/07/2023]
Abstract
PURPOSE A vertebral fracture is the most common complication of osteoporosis, and various factors are involved in its occurrence. The purpose of this study was to investigate the role of trabecular and cortical bone microstructure on vertebral strength using high-resolution peripheral quantitative computed tomography (HR-pQCT). METHODS Three female cadaveric spines were investigated (average age: 80.3 years). The whole spine (T1-L4) was scanned by second-generation HR-pQCT at a voxel size of 60.7 μm. Bone microstructure analysis and micro finite element analysis were performed after excluding the upper and lower endplates and posterior elements of a total of 48 vertebrae. Correlations between trabecular and cortical bone microstructure parameters and estimated vertebral strength were analyzed by univariate and multivariate regression models. RESULTS Cortical thickness (Ct.Th) and trabecular thickness (Tb.Th) were strongly correlated with estimated failure load on univariate analysis (r = 0.89, 0.82). Trabecular volumetric bone mineral density (Tb.vBMD), bone volume fraction (BV/TV), trabecular number (Tb.N), and Ct.Th were correlated with estimated failure load on multivariate regression analysis. CONCLUSIONS It was suggested that, in addition to trabecular bone (Tb.vBMD, BV/TV, Tb.N), cortical bone (Ct.Th) contributed significantly to vertebral strength in elderly women.
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Affiliation(s)
- Shuta Yamada
- Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan
| | - Ko Chiba
- Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan.
| | - Narihiro Okazaki
- Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan
| | - Makoto Era
- Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan
| | - Yuichiro Nishino
- Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan
| | - Kazuaki Yokota
- Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan
| | - Akihiko Yonekura
- Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan
| | - Masato Tomita
- Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan
| | - Toshiyuki Tsurumoto
- Department of Macroscopic Anatomy, Nagasaki University Graduate School of Biomedical Sciences, Japan
| | - Makoto Osaki
- Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan
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Knowles NK, G. Langohr GD, Faieghi M, Nelson A, Ferreira LM. Development of a validated glenoid trabecular density-modulus relationship. J Mech Behav Biomed Mater 2019; 90:140-145. [DOI: 10.1016/j.jmbbm.2018.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 08/16/2018] [Accepted: 10/04/2018] [Indexed: 10/28/2022]
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Anitha D, Subburaj K, Kopp FK, Mei K, Foehr P, Burgkart R, Sollmann N, Maegerlein C, Kirschke JS, Noel PB, Baum T. Effect of Statistically Iterative Image Reconstruction on Vertebral Bone Strength Prediction Using Bone Mineral Density and Finite Element Modeling: A Preliminary Study. J Comput Assist Tomogr 2019; 43:61-65. [PMID: 30211797 DOI: 10.1097/rct.0000000000000788] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Statistical iterative reconstruction (SIR) using multidetector computed tomography (MDCT) is a promising alternative to standard filtered back projection (FBP), because of lower noise generation while maintaining image quality. Hence, we investigated the feasibility of SIR in predicting MDCT-based bone mineral density (BMD) and vertebral bone strength from finite element (FE) analysis. The BMD and FE-predicted bone strength derived from MDCT images reconstructed using standard FBP (FFBP) and SIR with (FSIR) and without regularization (FSIRB0) were validated against experimental failure loads (Fexp). Statistical iterative reconstruction produced the best quality images with regard to noise, signal-to-noise ratio, and contrast-to-noise ratio. Fexp significantly correlated with FFBP, FSIR, and FSIRB0. FFBP had a significant correlation with FSIRB0 and FSIR. The BMD derived from FBP, SIRB0, and SIR were significantly correlated. Effects of regularization should be further investigated with FE and BMD analysis to allow for an optimal iterative reconstruction algorithm to be implemented in an in vivo scenario.
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Affiliation(s)
| | | | | | | | - Peter Foehr
- Department of Orthopaedic Surgery, Biomechanical Laboratory, and
| | - Rainer Burgkart
- Department of Orthopaedic Surgery, Biomechanical Laboratory, and
| | - Nico Sollmann
- Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Christian Maegerlein
- Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Jan S Kirschke
- Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | | | - Thomas Baum
- Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
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Knowles NK, Ip K, Ferreira LM. The Effect of Material Heterogeneity, Element Type, and Down-Sampling on Trabecular Stiffness in Micro Finite Element Models. Ann Biomed Eng 2018; 47:615-623. [PMID: 30362084 DOI: 10.1007/s10439-018-02152-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Accepted: 10/05/2018] [Indexed: 11/30/2022]
Abstract
Preclinical and clinical bone strength predictions can be elucidated by understanding bone mechanics at a variety of hierarchical levels. As such, down-sampled micro-CT images are often used to make comparisons across image resolutions or used to reduce computational resources in micro finite element models (µFEMs). Therefore, the objectives of this study were to compare trabecular apparent modulus among (i) hexahedral and tetrahedral µFEMs, (ii) µFEMs generated from 32, 64, and 64 µm down-sampled from 32 µm µCT scans, and (iii) µFEMs with homogeneous and heterogeneous tissue moduli. Trabecular µFEMs were generated from scans at the three spatial resolutions taken from the glenoid vault of 14 cadaveric specimens. Simulated unconstrained compression was performed and used to calculate and compare the apparent modulus of each µFEM. It was found that models derived from high-resolution images that account for material heterogeneity are nearly equivalent whether hexahedral or tetrahedral elements are used. However, translation of stiffness from down-sampled scans are not equivalent to scans performed at the down-sampled resolution, or that account for trabecular material heterogeneity. Material heterogeneity is most representative of in vivo trabecular bone and to accurately model trabecular mechanical properties, material heterogeneity should be considered in future µFEM development.
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Affiliation(s)
- Nikolas K Knowles
- School of Biomedical Engineering, The University of Western Ontario, London, ON, Canada.,Surgical Mechatronics Laboratory, Roth
- McFarlane Hand and Upper Limb Centre, St. Josephs Health Care, 268 Grosvenor St., London, ON, Canada.,Collaborative Training Program in MSK Health Research, and Bone and Joint Institute, The University of Western Ontario, London, ON, Canada
| | - Kenneth Ip
- School of Biomedical Engineering, The University of Western Ontario, London, ON, Canada.,Surgical Mechatronics Laboratory, Roth
- McFarlane Hand and Upper Limb Centre, St. Josephs Health Care, 268 Grosvenor St., London, ON, Canada
| | - Louis M Ferreira
- Department of Mechanical and Materials Engineering, The University of Western Ontario, London, ON, Canada. .,Surgical Mechatronics Laboratory, Roth
- McFarlane Hand and Upper Limb Centre, St. Josephs Health Care, 268 Grosvenor St., London, ON, Canada. .,Collaborative Training Program in MSK Health Research, and Bone and Joint Institute, The University of Western Ontario, London, ON, Canada.
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MDCT-based Finite Element Analysis of Vertebral Fracture Risk: What Dose is Needed? Clin Neuroradiol 2018; 29:645-651. [PMID: 30132090 DOI: 10.1007/s00062-018-0722-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/03/2018] [Indexed: 10/28/2022]
Abstract
PURPOSE The aim of this study was to compare vertebral failure loads, predicted from finite element (FE) analysis of patients with and without osteoporotic vertebral fractures (OVF) at virtually reduced dose levels, compared to standard-dose exposure from multidetector computed tomography (MDCT) imaging and evaluate whether ultra-low dose derived FE analysis can still differentiate patient groups. MATERIALS AND METHODS An institutional review board (IRB) approval was obtained for this retrospective study. A total of 16 patients were evaluated at standard-dose MDCT; eight with and eight without OVF. Images were reconstructed at virtually reduced dose levels (i. e. half, quarter and tenth of the standard dose). Failure load was determined at L1-3 from FE analysis and compared between standard, half, quarter, and tenth doses and used to differentiate between fracture and control groups. RESULTS Failure load derived at standard dose (3254 ± 909 N and 3794 ± 984 N) did not significantly differ from half (3390 ± 890 N and 3860 ± 1063 N) and quarter dose (3375 ± 915 N and 3925 ± 990 N) but was significantly higher for one tenth dose (4513 ± 1762 N and 4766 ± 1628 N) for fracture and control groups, respectively. Failure load differed significantly between the two groups at standard, half and quarter doses, but not at tenth dose. Receiver operating characteristic (ROC) curve analysis also demonstrated that standard, half, and quarter doses can significantly differentiate the fracture from the control group. CONCLUSION The use of MDCT enables a dose reduction of at least 75% compared to standard-dose for an adequate prediction of vertebral failure load based on non-invasive FE analysis.
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Lee DK, Song YK, Park BW, Cho HP, Yeom JS, Cho G, Cho H. The robustness of T 2 value as a trabecular structural index at multiple spatial resolutions of 7 Tesla MRI. Magn Reson Med 2018; 80:1949-1961. [PMID: 29656389 DOI: 10.1002/mrm.27202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/09/2018] [Accepted: 03/11/2018] [Indexed: 12/13/2022]
Abstract
PURPOSE To evaluate the robustness of MR transverse relaxation times of trabecular bone from spin-echo and gradient-echo acquisitions at multiple spatial resolutions of 7 T. METHODS The effects of MRI resolutions to T2 and T2* of trabecular bone were numerically evaluated by Monte Carlo simulations. T2 , T2*, and trabecular structural indices from multislice multi-echo and UTE acquisitions were measured in defatted human distal femoral condyles on a 7 T scanner. Reference structural indices were extracted from high-resolution microcomputed tomography images. For bovine knee trabecular samples with intact bone marrow, T2 and T2* were measured by degrading spatial resolutions on a 7 T system. RESULTS In the defatted trabecular experiment, both T2 and T2* values showed strong ( |r| > 0.80) correlations with trabecular spacing and number, at a high spatial resolution of 125 µm3 . The correlations for MR image-segmentation-derived structural indices were significantly degraded ( |r| < 0.50) at spatial resolutions of 250 and 500 µm3 . The correlations for T2* rapidly dropped ( |r| < 0.50) at a spatial resolution of 500 µm3 , whereas those for T2 remained consistently high ( |r| > 0.85). In the bovine trabecular experiments with intact marrow, low-resolution (approximately 1 mm3 , 2 minutes) T2 values did not shorten ( |r| > 0.95 with respect to approximately 0.4 mm3 , 11 minutes) and maintained consistent correlations ( |r| > 0.70) with respect to trabecular spacing (turbo spin echo, 22.5 minutes). CONCLUSION T2 measurements of trabeculae at 7 T are robust with degrading spatial resolution and may be preferable in assessing trabecular spacing index with reduced scan time, when high-resolution 3D micro-MRI is difficult to obtain.
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Affiliation(s)
- D K Lee
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea
| | - Y K Song
- Korea Basic Science Institute, Ochang, South Korea
| | - B W Park
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea
| | - H P Cho
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea
| | - J S Yeom
- Department of Orthopedic Surgery, Seoul National University, Seoul, South Korea
| | - G Cho
- Korea Basic Science Institute, Ochang, South Korea
| | - H Cho
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea
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Mookiah MRK, Rohrmeier A, Dieckmeyer M, Mei K, Kopp FK, Noel PB, Kirschke JS, Baum T, Subburaj K. Feasibility of opportunistic osteoporosis screening in routine contrast-enhanced multi detector computed tomography (MDCT) using texture analysis. Osteoporos Int 2018; 29:825-835. [PMID: 29322221 DOI: 10.1007/s00198-017-4342-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 12/04/2017] [Indexed: 10/18/2022]
Abstract
UNLABELLED This study investigated the feasibility of opportunistic osteoporosis screening in routine contrast-enhanced MDCT exams using texture analysis. The results showed an acceptable reproducibility of texture features, and these features could discriminate healthy/osteoporotic fracture cohort with an accuracy of 83%. INTRODUCTION This aim of this study is to investigate the feasibility of opportunistic osteoporosis screening in routine contrast-enhanced MDCT exams using texture analysis. METHODS We performed texture analysis at the spine in routine MDCT exams and investigated the effect of intravenous contrast medium (IVCM) (n = 7), slice thickness (n = 7), the long-term reproducibility (n = 9), and the ability to differentiate healthy/osteoporotic fracture cohort (n = 9 age and gender matched pairs). Eight texture features were extracted using gray level co-occurrence matrix (GLCM). The independent sample t test was used to rank the features of healthy/fracture cohort and classification was performed using support vector machine (SVM). RESULTS The results revealed significant correlations between texture parameters derived from MDCT scans with and without IVCM (r up to 0.91) slice thickness of 1 mm versus 2 and 3 mm (r up to 0.96) and scan-rescan (r up to 0.59). The performance of the SVM classifier was evaluated using 10-fold cross-validation and revealed an average classification accuracy of 83%. CONCLUSIONS Opportunistic osteoporosis screening at the spine using specific texture parameters (energy, entropy, and homogeneity) and SVM can be performed in routine contrast-enhanced MDCT exams.
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Affiliation(s)
- M R K Mookiah
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore
| | - A Rohrmeier
- Department of Radiology, Klinikum Landshut Achdorf, Landshut, Germany
- Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - M Dieckmeyer
- Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - K Mei
- Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - F K Kopp
- Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - P B Noel
- Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - J S Kirschke
- Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - T Baum
- Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - K Subburaj
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore.
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Wen XX, Yu HL, Yan YB, Zong CL, Ding HJ, Ma XY, Wang TS, Lei W. Influence of the shape of the micro-finite element model on the mechanical properties calculated from micro-finite element analysis. Exp Ther Med 2017; 14:1744-1748. [PMID: 28810645 DOI: 10.3892/etm.2017.4709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 04/21/2017] [Indexed: 11/05/2022] Open
Abstract
Assessing the biomechanical properties of trabecular bone is of major biological and clinical significance for the research of bone diseases, fractures and their treatments. Micro-finite element (µFE) models are becoming increasingly popular for investigating the biomechanical properties of trabecular bone. The shapes of µFE models typically include cube and cylinder. Whether there are differences between cubic and cylindrical µFE models has not yet been studied. In the present study, cubic and cylindrical µFE models of human vertebral trabecular bone were constructed. A 1% strain was prescribed to the model along the superior-inferior direction. E values were calculated from these models, and paired t-tests were performed to determine whether these were any differences between E values obtained from cubic and cylindrical models. The results demonstrated that there were no statistically significant differences in the E values between cubic and cylindrical models, and there were no significant differences in Von Mises stress distributions between the two models. These findings indicated that, to construct µFE models of vertebral trabecular bone, cubic or cylindrical models were both feasible. Choosing between the cubic or cylindrical µFE model is dependent upon the specific study design.
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Affiliation(s)
- Xin-Xin Wen
- Department of Orthopedics, 463 Hospital of PLA, Shenyang, Liaoning 110042, P.R. China
| | - Hai-Long Yu
- Department of Orthopedics, General Hospital of Shenyang Military Area Command of PLA, Rescue Center of Severe Wound and Trauma of PLA, Shenyang, Liaoning 110016, P.R. China
| | - Ya-Bo Yan
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Chun-Lin Zong
- Department of Cranio-facial Trauma and Orthognathic Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Hai-Jiao Ding
- Department of Orthopedics, 463 Hospital of PLA, Shenyang, Liaoning 110042, P.R. China
| | - Xiang-Yu Ma
- Department of Orthopedics, 463 Hospital of PLA, Shenyang, Liaoning 110042, P.R. China
| | - Tian-Sheng Wang
- Department of Orthopedics, 463 Hospital of PLA, Shenyang, Liaoning 110042, P.R. China
| | - Wei Lei
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
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18
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Skeletal assessment with finite element analysis: relevance, pitfalls and interpretation. Curr Opin Rheumatol 2017; 29:402-409. [PMID: 28376059 DOI: 10.1097/bor.0000000000000405] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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19
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Bissinger O, Probst FA, Wolff KD, Jeschke A, Weitz J, Deppe H, Kolk A. Comparative 3D micro-CT and 2D histomorphometry analysis of dental implant osseointegration in the maxilla of minipigs. J Clin Periodontol 2017; 44:418-427. [DOI: 10.1111/jcpe.12693] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Oliver Bissinger
- Department of Oral and Maxillofacial Surgery; Klinikum rechts der Isar der Technischen Universität München; Munich Germany
| | - Florian Andreas Probst
- Department of Oral and Maxillofacial Surgery; Ludwig-Maximilians-University of Munich; Munich Germany
| | - Klaus-Dietrich Wolff
- Department of Oral and Maxillofacial Surgery; Klinikum rechts der Isar der Technischen Universität München; Munich Germany
| | - Anke Jeschke
- Department of Osteology and Biomechanics; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - Jochen Weitz
- Department of Oral and Maxillofacial Surgery; Klinikum rechts der Isar der Technischen Universität München; Munich Germany
| | - Herbert Deppe
- Department of Oral and Maxillofacial Surgery; Klinikum rechts der Isar der Technischen Universität München; Munich Germany
| | - Andreas Kolk
- Department of Oral and Maxillofacial Surgery; Klinikum rechts der Isar der Technischen Universität München; Munich Germany
- Institute of Molecular Immunology - Experimental Oncology; Klinikum rechts der Isar der Technischen Universität München; Munich Germany
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Takano H, Yonezawa I, Todo M, Hazli Mazlan M, Sato T, Kaneko K. Biomechanical Study of Vertebral Compression Fracture Using Finite Element Analysis. ACTA ACUST UNITED AC 2017. [DOI: 10.4236/jamp.2017.54084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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21
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Micro-CT vs. Whole Body Multirow Detector CT for Analysing Bone Regeneration in an Animal Model. PLoS One 2016; 11:e0166540. [PMID: 27880788 PMCID: PMC5120815 DOI: 10.1371/journal.pone.0166540] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 10/31/2016] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVES Compared with multirow detector CT (MDCT), specimen (ex vivo) micro-CT (μCT) has a significantly higher (~ 30 x) spatial resolution and is considered the gold standard for assessing bone above the cellular level. However, it is expensive and time-consuming, and when applied in vivo, the radiation dose accumulates considerably. The aim of this study was to examine whether the lower resolution of the widely used MDCT is sufficient to qualitatively and quantitatively evaluate bone regeneration in rats. METHODS Forty critical-size defects (5mm) were placed in the mandibular angle of rats and covered with coated bioactive titanium implants to promote bone healing. Five time points were selected (7, 14, 28, 56 and 112 days). μCT and MDCT were used to evaluate the defect region to determine the bone volume (BV), tissue mineral density (TMD) and bone mineral content (BMC). RESULTS MDCT constantly achieved higher BV values than μCT (10.73±7.84 mm3 vs. 6.62±4.96 mm3, p<0.0001) and consistently lower TMD values (547.68±163.83 mm3 vs. 876.18±121.21 mm3, p<0.0001). No relevant difference was obtained for BMC (6.48±5.71 mm3 vs. 6.15±5.21 mm3, p = 0.40). BV and BMC showed very strong correlations between both methods, whereas TMD was only moderately correlated (r = 0.87, r = 0.90, r = 0.68, p < 0.0001). CONCLUSIONS Due to partial volume effects, MDCT overestimated BV and underestimated TMD but accurately determined BMC, even in small volumes, compared with μCT. Therefore, if bone quantity is a sufficient end point, a considerable number of animals and costs can be saved, and compared with in vivo μCT, the required dose of radiation can be reduced.
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Alkalay RN, Harrigan TP. Mechanical assessment of the effects of metastatic lytic defect on the structural response of human thoracolumbar spine. J Orthop Res 2016; 34:1808-1819. [PMID: 26748564 DOI: 10.1002/jor.23154] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 12/29/2015] [Indexed: 02/04/2023]
Abstract
To investigate the effects of a clinical lytic defect on the structural response of human thoracolumbar functional spinal unit. A novel CT-compatible mechanical test system was used to image the deformation of a T12-L1 motion segment and measure the change in strain response under compressive loads ranging from 50 to 750 N. A lytic lesion (LM) with cortex involvement (33% by volume) was introduced to the upper vertebral body and the CT experiments were repeated. Finite element models, established from the CT volumes, were used to investigate the defect's effects on the structural response and the state of principal and shear stresses within the affected and adjacent vertebrae. The lytic lesion resulted in severe loss of the vertebral structural competence, resulting in significant, non-linear, and asymmetric increase in the experimentally measured strains and computed stresses within both vertebrae (p < 0.01). At the cortex, the tensile strains were significantly increased, while compressive strains significantly decreased, (p < 0.05). Both the vertebral bone and cortex regions adjacent to the defect showed significant increase in computed compressive, tensile, and shear stresses (p < 0.01). Changes in stress and strain distribution within the affected and adjacent vertebral bone and the experimentally observed bulging and buckling of the vertebral cortices suggested that initiation of catastrophic vertebral failure may occur under load magnitudes encountered in daily living. Although the effect of LM on the global deformation of the spine was well-predicted, our results show that FE predictions of local strain changes must be carefully assessed for clinical relevance. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1808-1819, 2016.
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Affiliation(s)
- Ron N Alkalay
- Center for Advanced Orthopedic Studies, Department of Orthopedic Surgery, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Avenue, Boston, Massachusetts, 02215.
| | - Timothy P Harrigan
- Applied Physics Laboratory, Johns Hopkins University, 11100 Johns Hopkins Road Laurel, Maryland, 20723
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Fluorescence molecular tomography of DiR-labeled mesenchymal stem cell implants for osteochondral defect repair in rabbit knees. Eur Radiol 2016; 27:1105-1113. [PMID: 27329519 DOI: 10.1007/s00330-016-4457-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/25/2016] [Accepted: 05/30/2016] [Indexed: 12/21/2022]
Abstract
OBJECTIVES To assess labelling efficiency of rabbit mesenchymal stem cells (MSCs) using the near-infrared dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine iodide (DiR) and detection of labelled MSCs for osteochondral defect repair in a rabbit model using fluorescence molecular tomography-X-ray computed tomography (FMT-XCT). METHODS MSCs were isolated from New Zealand White rabbits and labelled with DiR (1.25-20 μg/mL). Viability and induction of apoptosis were assessed by XTT- and Caspase-3/-7-testing. Chondrogenic potential was evaluated by measurement of glycosaminoglycans. Labelled cells and unlabeled controls (n = 3) underwent FMT-XCT imaging before and after chondrogenic differentiation. Osteochondral defects were created surgically in rabbit knees (n = 6). Unlabeled and labelled MSCs were implanted in fibrin-clots and imaged by FMT-XCT. Statistical analyses were performed using multiple regression models. RESULTS DiR-labelling of MSCs resulted in a dose-dependent fluorescence signal on planar images in trans-illumination mode. No significant reduction in viability or induction of apoptosis was detected at concentrations below 10 μg DiR/mL (p > .05); the chondrogenic potential of MSCs was not affected (p > .05). FMT-XCT of labelled MSCs in osteochondral defects showed a significant signal of the transplant (p < .05) with additional high-resolution anatomical information about its osteochondral integration. CONCLUSIONS FMT-XCT allows for detection of stem cell implantation within osteochondral regeneration processes. KEY POINTS • DiR-labelling of MSCs shows no toxic side effects or impairment of chondrogenesis. • Fluorescence molecular tomography allows for detection of MSCs for osteochondral defect repair. • FMT-XCT helps to improve evaluation of cell implantation and osteochondral regeneration processes.
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Srinivasan P, Miller MA, Verdonschot N, Mann KA, Janssen D. Experimental and computational micromechanics at the tibial cement-trabeculae interface. J Biomech 2016; 49:1641-1648. [PMID: 27079621 DOI: 10.1016/j.jbiomech.2016.03.054] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 03/11/2016] [Accepted: 03/28/2016] [Indexed: 02/05/2023]
Abstract
Aseptic loosening of the tibial component in cemented total knee arthroplasty remains a major concern. We hypothesize that micromotion between the cement and trabeculae leads to increased circulation of interstitial fluid which in turn causes fluid-induced resorption of the trabeculae. Another mechanism for implant loosening is trabecular strain shielding. Using a newly developed experimental setup and digital image correlation (DIC) methods we were able to measure micromotion and strains in lab-prepared cement-trabeculae interface specimens (n=4). Finite element (FE) models of these specimens were developed to determine whether differences in micromotion and strain in morphologically varying specimens could be simulated accurately. Results showed that the measured micromotion and strains correlated well with FE model predictions (r(2)=0.59-0.85; r(2)=0.66-0.90). Global specimen strains measured axially matched well with the FE model strains (r(2)=0.87). FE model cement strains showed an increasing trend with distance from the cement border. The influence of loss of trabecular connectivity at the specimen edges was studied using our FE model results. Micromotion values at the outer edge of the specimens were higher than the specimen interior when considering a very thin outer edge (0.1mm). When the outer edge thickness was increased to about one trabecular length (0.8mm), there was a drop in the median and peak values. Using the experimental and modelling approach outlined in this study, we can further study the mechanisms that lead to loss of interlock between cement and trabeculae at the tibial interface.
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Affiliation(s)
- Priyanka Srinivasan
- Radboud university medical center, Radboud Institute for Health Sciences, Orthopaedic Research Laboratory, Nijmegen, The Netherlands.
| | - Mark A Miller
- Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Nico Verdonschot
- Radboud university medical center, Radboud Institute for Health Sciences, Orthopaedic Research Laboratory, Nijmegen, The Netherlands; University of Twente, Laboratory for Biomechanical Engineering, Faculty of Engineering Technology, Enschede, The Netherlands
| | - Kenneth A Mann
- Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Dennis Janssen
- Radboud university medical center, Radboud Institute for Health Sciences, Orthopaedic Research Laboratory, Nijmegen, The Netherlands
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Wen XX, Xu C, Zong CL, Feng YF, Ma XY, Wang FQ, Yan YB, Lei W. Relationship between sample volumes and modulus of human vertebral trabecular bone in micro-finite element analysis. J Mech Behav Biomed Mater 2016; 60:468-475. [PMID: 26999702 DOI: 10.1016/j.jmbbm.2016.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/04/2016] [Accepted: 03/07/2016] [Indexed: 01/24/2023]
Abstract
Micro-finite element (μFE) models have been widely used to assess the biomechanical properties of trabecular bone. How to choose a proper sample volume of trabecular bone, which could predict the real bone biomechanical properties and reduce the calculation time, was an interesting problem. Therefore, the purpose of this study was to investigate the relationship between different sample volumes and apparent elastic modulus (E) calculated from μFE model. 5 Human lumbar vertebral bodies (L1-L5) were scanned by micro-CT. Cubic concentric samples of different lengths were constructed as the experimental groups and the largest possible volumes of interest (VOI) were constructed as the control group. A direct voxel-to-element approach was used to generate μFE models and steel layers were added to the superior and inferior surface to mimic axial compression tests. A 1% axial strain was prescribed to the top surface of the model to obtain the E values. ANOVA tests were performed to compare the E values from the different VOIs against that of the control group. Nonlinear function curve fitting was performed to study the relationship between volumes and E values. The larger cubic VOI included more nodes and elements, and more CPU times were needed for calculations. E values showed a descending tendency as the length of cubic VOI decreased. When the volume of VOI was smaller than (7.34mm(3)), E values were significantly different from the control group. The fit function showed that E values approached an asymptotic values with increasing length of VOI. Our study demonstrated that apparent elastic modulus calculated from μFE models were affected by the sample volumes. There was a descending tendency of E values as the length of cubic VOI decreased. Sample volume which was not smaller than (7.34mm(3)) was efficient enough and timesaving for the calculation of E.
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Affiliation(s)
- Xin-Xin Wen
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China
| | - Chao Xu
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China
| | - Chun-Lin Zong
- State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, China
| | - Ya-Fei Feng
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China
| | - Xiang-Yu Ma
- Department of Orthopedics, 463 Hospital of PLA, Shenyang, China
| | - Fa-Qi Wang
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China
| | - Ya-Bo Yan
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China.
| | - Wei Lei
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi׳an, Shaanxi 710032, China.
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Mao SS, Li D, Luo Y, Syed YS, Budoff MJ. Application of quantitative computed tomography for assessment of trabecular bone mineral density, microarchitecture and mechanical property. Clin Imaging 2016; 40:330-8. [DOI: 10.1016/j.clinimag.2015.09.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/17/2015] [Accepted: 09/10/2015] [Indexed: 12/17/2022]
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Kubicek L, Vanderhart D, Wirth K, An Q, Chang M, Farese J, Bova F, Sudhyadhom A, Kow K, Bacon NJ, Milner R. ASSOCIATION BETWEEN COMPUTED TOMOGRAPHIC CHARACTERISTICS AND FRACTURES FOLLOWING STEREOTACTIC RADIOSURGERY IN DOGS WITH APPENDICULAR OSTEOSARCOMA. Vet Radiol Ultrasound 2016; 57:321-30. [PMID: 26916056 DOI: 10.1111/vru.12351] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 11/07/2015] [Accepted: 11/09/2015] [Indexed: 11/29/2022] Open
Abstract
The objective of this observational, descriptive, retrospective study was to report CT characteristics associated with fractures following stereotactic radiosurgery in canine patients with appendicular osteosarcoma. Medical records (1999 and 2012) of dogs that had a diagnosis of appendicular osteosarcoma and undergone stereotactic radiosurgery were reviewed. Dogs were included in the study if they had undergone stereotactic radiosurgery for an aggressive bone lesion with follow-up information regarding fracture status, toxicity, and date and cause of death. Computed tomography details, staging, chemotherapy, toxicity, fracture status and survival data were recorded. Overall median survival time (MST) and fracture rates of treated dogs were calculated. CT characteristics were evaluated for association with time to fracture. Forty-six dogs met inclusion criteria. The median overall survival time was 9.7 months (95% CI: 6.9-14.3 months). The fracture-free rates at 3, 6, and 9 months were 73%, 44%, and 38% (95% CI: 60-86%, 29-60%, and 22-54%), respectively. The region of bone affected was significantly associated with time to fracture. The median time to fracture was 4.2 months in dogs with subchondral bone involvement and 16.3 months in dogs without subchondral bone involvement (P-value = 0.027, log-rank test). Acute and late skin effects were present in 58% and 16% of patients, respectively. Findings demonstrated a need for improved patient selection for this procedure, which can be aided by CT-based prognostic factors to predict the likelihood of fracture.
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Affiliation(s)
- Lyndsay Kubicek
- Department of Small Animal Clinical Sciences, University of Florida, Gainesville, FL, 32611.,Angell Animal Medical Center, Jamaica Plain, MA, Boston, MA, 02130
| | - Daniel Vanderhart
- Department of Small Animal Clinical Sciences, University of Florida, Gainesville, FL, 32611
| | - Kimberly Wirth
- Department of Small Animal Clinical Sciences, University of Florida, Gainesville, FL, 32611
| | - Qi An
- Department of Biostatistics, University of Florida, Gainesville, FL, 32611
| | - Myron Chang
- Department of Biostatistics, University of Florida, Gainesville, FL, 32611
| | - James Farese
- Pet Emergency and Specialty Center of Marin, San Rafael, CA, 94901
| | - Francis Bova
- Department of Neurosurgery, McKnight Brain Institute, University of Florida, Gainesville, FL, 32611
| | - Atchar Sudhyadhom
- the Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, 94143
| | - Kelvin Kow
- Department of Small Animal Clinical Sciences, University of Florida, Gainesville, FL, 32611
| | - Nicholas J Bacon
- Department of Small Animal Clinical Sciences, University of Florida, Gainesville, FL, 32611
| | - Rowan Milner
- Department of Small Animal Clinical Sciences, University of Florida, Gainesville, FL, 32611
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Takano H, Yonezawa I, Todo M, Mazlan MH, Sato T, Kaneko K. Biomechanical Study of the Effects of Balloon Kyphoplasty on the Adjacent Vertebrae. ACTA ACUST UNITED AC 2016. [DOI: 10.4236/jbise.2016.910043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Lowitz T, Museyko O, Bousson V, Kalender WA, Laredo JD, Engelke K. Characterization of knee osteoarthritis-related changes in trabecular bone using texture parameters at various levels of spatial resolution-a simulation study. BONEKEY REPORTS 2014; 3:615. [PMID: 25512855 DOI: 10.1038/bonekey.2014.110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 10/24/2014] [Indexed: 12/21/2022]
Abstract
Articular cartilage and subchondral bone are the key tissues in osteoarthritis (OA). The role of the cancellous bone increasingly attracts attention in OA research. Because of its fast adaptation to changes in the loading distribution across joints, its quantification is expected to improve the diagnosis and monitoring of OA. In this study, we simulated OA progression-related changes of trabecular structure in a series of digital bone models and then characterized the potential of texture parameters and bone mineral density (BMD) as surrogate measures to quantify trabecular bone structure. Five texture parameters were studied: entropy, global and local inhomogeneity, anisotropy and variogram slope. Their dependence on OA relevant structural changes was investigated for three spatial resolutions typically used in micro computed tomography (CT; 10 μm), high-resolution peripheral quantitative CT (HR-pQCT) (90 μm) and clinical whole-body CT equipment (250 μm). At all resolutions, OA-related changes in trabecular bone architecture can be quantified using a specific (resolution dependent) combination of three texture parameters. BMD alone is inadequate for this purpose but if available reduces the required texture parameter combination to anisotropy and global inhomogeneity. The results are summarized in a comprehensive analysis guide for the detection of structural changes in OA knees. In conclusion, texture parameters can be used to characterize trabecular bone architecture even at spatial resolutions below the dimensions of a single trabecula and are essential for a detailed classification of relevant OA changes that cannot be achieved with a measurement of BMD alone.
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Affiliation(s)
- Torsten Lowitz
- Institute of Medical Physics, University of Erlangen-Nürnberg , Erlangen, Germany
| | - Oleg Museyko
- Institute of Medical Physics, University of Erlangen-Nürnberg , Erlangen, Germany
| | - Valerie Bousson
- Service de Radiologie Ostéo-Articulaire - Assistance Publique-Hopitaux de Paris, Hôpital Lariboisière , Paris, France ; Univ Paris Diderot, Sorbonne Paris Cité, CNRS UMR 7052 , Paris, France
| | - Willi A Kalender
- Institute of Medical Physics, University of Erlangen-Nürnberg , Erlangen, Germany
| | - Jean Denis Laredo
- Service de Radiologie Ostéo-Articulaire - Assistance Publique-Hopitaux de Paris, Hôpital Lariboisière , Paris, France ; Univ Paris Diderot, Sorbonne Paris Cité, CNRS UMR 7052 , Paris, France
| | - Klaus Engelke
- Institute of Medical Physics, University of Erlangen-Nürnberg , Erlangen, Germany
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