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Yadav RN, Oravec DJ, Morrison CK, Bevins NB, Rao SD, Yeni YN. Digital wrist tomosynthesis (DWT)-based finite element analysis of ultra-distal radius differentiates patients with and without a history of osteoporotic fracture. Bone 2023; 177:116901. [PMID: 37714502 DOI: 10.1016/j.bone.2023.116901] [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: 07/10/2023] [Revised: 09/03/2023] [Accepted: 09/12/2023] [Indexed: 09/17/2023]
Abstract
Despite effective therapies for those at risk of osteoporotic fracture, low adherence to screening guidelines and limited accuracy of bone mineral density (BMD) in predicting fracture risk preclude identification of those at risk. Because of high adherence to routine mammography, bone health screening at the time of mammography using a digital breast tomosynthesis (DBT) scanner has been suggested as a potential solution. BMD and bone microstructure can be measured from the wrist using a DBT scanner. However, the extent to which biomechanical variables can be derived from digital wrist tomosynthesis (DWT) has not been explored. Accordingly, we measured stiffness from a DWT based finite element (DWT-FE) model of the ultra-distal (UD) radius and ulna, and correlate these to reference microcomputed tomography image based FE (μCT-FE) from five cadaveric forearms. Further, this method is implemented to determine in vivo reproducibility of FE derived stiffness of UD radius and demonstrate the in vivo utility of DWT-FE in bone quality assessment by comparing two groups of postmenopausal women with and without a history of an osteoporotic fracture (Fx; n = 15, NFx; n = 51). Stiffness obtained from DWT and μCT had a strong correlation (R2 = 0.87, p < 0.001). In vivo repeatability error was <5 %. The NFx and Fx groups were not significantly different in DXA derived minimum T-scores (p > 0.3), but stiffness of the UD radius was lower for the Fx group (p < 0.007). Logistic regression models of fracture status with stiffness of the nondominant arm as the predictor were significant (p < 0.01). In conclusion this study demonstrates the feasibility of fracture risk assessment in mammography settings using DWT imaging and FE modeling in vivo. Using this approach, bone and breast screening can be performed in a single visit, with the potential to improve both the prevalence of bone health screening and the accuracy of fracture risk assessment.
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Affiliation(s)
- Ram N Yadav
- Bone and Joint Center, Henry Ford Health, Detroit, MI, USA
| | | | | | | | - Sudhaker D Rao
- Division of Endocrinology, Diabetes and Bone, Mineral Disorders, and Bone, Mineral Research Laboratory, Henry Ford Health, Detroit, MI, USA
| | - Yener N Yeni
- Bone and Joint Center, Henry Ford Health, Detroit, MI, USA; Henry Ford Health + Michigan State University Health Sciences, Detroit, MI, USA.
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Vu BTD, Jones BC, Lee H, Kamona N, Deshpande RS, Wehrli FW, Rajapakse CS. Six-minute, in vivo MRI quantification of proximal femur trabecular bone 3D microstructure. Bone 2023; 177:116900. [PMID: 37714503 DOI: 10.1016/j.bone.2023.116900] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/29/2023] [Accepted: 09/12/2023] [Indexed: 09/17/2023]
Abstract
BACKGROUND Assessment of proximal femur trabecular bone microstructure in vivo by magnetic resonance imaging has recently been validated for acquiring information independent of bone mineral density in osteoporotic patients. However, the requisite signal-to-noise ratio (SNR) and resolution for interrogation of the trabecular microstructure at this anatomical location prolongs the scan duration and renders the imaging protocol clinically infeasible. Parallel imaging and compressed sensing (PICS) techniques can reduce the scan duration of the imaging protocol without substantially compromising image quality. The present work investigates the limits of acceleration for a commonly used PICS technique, ℓ1-ESPIRiT, for the purpose of quantifying measures of trabecular bone microarchitecture. Based on a desired error tolerance, a six-minute, prospectively accelerated variant of the imaging protocol was developed and assessed for intersession reproducibility and agreement with the longer reference scan. PURPOSE To investigate the limits of acceleration for MRI-based trabecular bone quantification by parallel imaging and compressed sensing reconstruction, and to develop a prototypical imaging protocol for assessing the proximal femur microstructure in a clinically practical scan time. METHODS Healthy participants (n = 11) were scanned by a 3D balanced steady-state free precession (bSSFP) sequence satisfying the Nyquist criterion with a scan duration of about 18 min. The raw data were retrospectively undersampled and reconstructed to mimic various acceleration factors ranging from 2 to 6. Trabecular volumes-of-interest in four major femoral regions (greater trochanter, intertrochanteric region, femoral neck, and femoral head) were analyzed and six relevant measures of trabecular bone microarchitecture (bone volume fraction, surface-to-curve ratio, erosion index, elastic modulus, trabecular thickness, plates-to-rods ratio) were obtained for images of all accelerations. To assess agreement, median percent error and intraclass correlation coefficients (ICCs) were computed using the fully-sampled data as reference. Based on this analysis, a prospectively 3-fold accelerated sequence with a duration of about 6 min was developed and the analysis was repeated. RESULTS A prospective acceleration factor of 3 demonstrated comparable performance in reproducibility and absolute agreement to the fully-sampled scan. The median CoV over all image-derived metrics was generally <6 % and ICCs >0.70. Also, measurements from prospectively 3-fold accelerated scans demonstrated in general median percent errors of <7 % and ICCs >0.70. CONCLUSION The present work proposes a method to make in vivo quantitative assessment of proximal femur trabecular microstructure with a clinically practical scan duration of about 6 min.
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Affiliation(s)
- Brian-Tinh Duc Vu
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Founders Building, 3400 Spruce St, Philadelphia, PA 19104, United States of America; Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, 210 South 33(rd) St, Philadelphia, PA 19104, United States of America.
| | - Brandon C Jones
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Founders Building, 3400 Spruce St, Philadelphia, PA 19104, United States of America; Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, 210 South 33(rd) St, Philadelphia, PA 19104, United States of America
| | - Hyunyeol Lee
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Founders Building, 3400 Spruce St, Philadelphia, PA 19104, United States of America; School of Electronics Engineering, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, South Korea
| | - Nada Kamona
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Founders Building, 3400 Spruce St, Philadelphia, PA 19104, United States of America; Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, 210 South 33(rd) St, Philadelphia, PA 19104, United States of America
| | - Rajiv S Deshpande
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Founders Building, 3400 Spruce St, Philadelphia, PA 19104, United States of America; Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, 210 South 33(rd) St, Philadelphia, PA 19104, United States of America
| | - Felix W Wehrli
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Founders Building, 3400 Spruce St, Philadelphia, PA 19104, United States of America
| | - Chamith S Rajapakse
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Founders Building, 3400 Spruce St, Philadelphia, PA 19104, United States of America; Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104, United States of America
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Chan TJ, Rajapakse CS. A Super-Resolution Diffusion Model for Recovering Bone Microstructure from CT Images. Radiol Artif Intell 2023; 5:e220251. [PMID: 38074790 PMCID: PMC10698592 DOI: 10.1148/ryai.220251] [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: 11/15/2022] [Revised: 08/02/2023] [Accepted: 09/01/2023] [Indexed: 02/12/2024]
Abstract
Purpose To use a diffusion-based deep learning model to recover bone microstructure from low-resolution images of the proximal femur, a common site of traumatic osteoporotic fractures. Materials and Methods Training and testing data in this retrospective study consisted of high-resolution cadaveric micro-CT scans (n = 26), which served as ground truth. The images were downsampled prior to use for model training. The model was used to increase spatial resolution in these low-resolution images threefold, from 0.72 mm to 0.24 mm, sufficient to visualize bone microstructure. Model performance was validated using microstructural metrics and finite element simulation-derived stiffness of trabecular regions. Performance was also evaluated across a handful of image quality assessment metrics. Correlations between model performance and ground truth were assessed using intraclass correlation coefficients (ICCs) and Pearson correlation coefficients. Results Compared with popular deep learning baselines, the proposed model exhibited greater accuracy (mean ICC of proposed model, 0.92 vs ICC of next best method, 0.83) and lower bias (mean difference in means, 3.80% vs 10.00%, respectively) across the physiologic metrics. Two gradient-based image quality metrics strongly correlated with accuracy across structural and mechanical criteria (r > 0.89). Conclusion The proposed method may enable accurate measurements of bone structure and strength with a radiation dose on par with current clinical imaging protocols, improving the viability of clinical CT for assessing bone health.Keywords: CT, Image Postprocessing, Skeletal-Appendicular, Long Bones, Radiation Effects, Quantification, Prognosis, Semisupervised Learning Online supplemental material is available for this article. © RSNA, 2023.
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Affiliation(s)
- Trevor J Chan
- From the Departments of Bioengineering (T.J.C.), Radiology (T.J.C., C.S.R.), and Orthopedic Surgery (C.S.R.), University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104-6243
| | - Chamith S Rajapakse
- From the Departments of Bioengineering (T.J.C.), Radiology (T.J.C., C.S.R.), and Orthopedic Surgery (C.S.R.), University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104-6243
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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: 0] [Impact Index Per Article: 0] [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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Characterizing the Mechanical Behavior of Bone and Bone Surrogates in Compression Using pQCT. MATERIALS 2022; 15:ma15145065. [PMID: 35888531 PMCID: PMC9320168 DOI: 10.3390/ma15145065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/12/2022] [Accepted: 07/18/2022] [Indexed: 01/27/2023]
Abstract
Many axial and appendicular skeleton bones are subjected to repetitive loading during daily activities. Until recently, the structural analysis of fractures has been limited to 2D sections, and the dynamic assessment of fracture progression has not been possible. The structural failure was analyzed using step-wise micro-compression combined with time-lapsed micro-computed tomographic imaging. The structural failure was investigated in four different sample materials (two different bone surrogates, lumbar vertebral bodies from bovine and red deer). The samples were loaded in different force steps based on uniaxial compression tests. The micro-tomography images were used to create three-dimensional models from which various parameters were calculated that provide information about the structure and density of the samples. By superimposing two 3D images and calculating the different surfaces, it was possible to precisely analyze which trabeculae failed in which area and under which load. According to the current state of the art, bone mineral density is usually used as a value for bone quality, but the question can be raised as to whether other values such as trabecular structure, damage accumulation, and bone mineralization can predict structural competence better than bone mineral density alone.
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Jerban S, Alenezi S, Afsahi AM, Ma Y, Du J, Chung CB, Chang EY. MRI-based mechanical competence assessment of bone using micro finite element analysis (micro-FEA): Review. Magn Reson Imaging 2022; 88:9-19. [PMID: 35091024 PMCID: PMC8988995 DOI: 10.1016/j.mri.2022.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 12/09/2021] [Accepted: 01/20/2022] [Indexed: 12/18/2022]
Abstract
Areal bone mineral density (aBMD) from dual-energy x-ray absorptiometry (DEXA) and volumetric bone mineral density (vBMD) have demonstrated limited capabilities in the evaluation of bone mechanical competence and prediction of bone fracture. Predicting the macroscopic mechanical behavior of the bone structure has been challenging because of the heterogeneous and anisotropic nature of bone, such as the dependencies on loading direction, anatomical location, and sample dimensions. Magnetic resonance imaging (MRI) has been introduced as a promising modality that can be coupled with finite element analysis (FEA) for the assessment of bone mechanical competence. This review article describes studies investigating MRI-based micro-FEA as a potential non-invasive method to predict bone mechanical competence and facilitate bone fracture risk estimation without exposure to ionizing radiation. Specifically, the steps, applications, and future potential of FEA using indirect and direct bone imaging are discussed.
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Affiliation(s)
- Saeed Jerban
- Department of Radiology, University of California, San Diego, CA, USA.
| | - Salem Alenezi
- Research and Laboratories Sector, Saudi Food and Drug Authority, Saudi Arabia
| | | | - Yajun Ma
- Department of Radiology, University of California, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA, USA; Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Christine B Chung
- Department of Radiology, University of California, San Diego, CA, USA; Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, CA, USA; Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA.
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Martel D, Monga A, Chang G. Osteoporosis Imaging. Radiol Clin North Am 2022; 60:537-545. [DOI: 10.1016/j.rcl.2022.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Guha I, Zhang X, Rajapakse CS, Letuchy EM, Chang G, Janz KF, Torner JC, Levy SM, Saha PK. CT
‐based Stiffness Measures of Trabecular Bone Microstructure — Cadaveric Validation and
In Vivo
Application. JBMR Plus 2022; 6:e10627. [PMID: 35720662 PMCID: PMC9189917 DOI: 10.1002/jbm4.10627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 03/14/2022] [Accepted: 03/29/2022] [Indexed: 11/09/2022] Open
Abstract
Osteoporosis causes bone fragility and elevates fracture risk. Applications of finite element (FE) analysis (FEA) for assessment of trabecular bone (Tb) microstructural strength at whole‐body computed tomography (CT) imaging are limited due to challenges with Tb microstructural segmentation. We present a nonlinear FEA method for distal tibia CT scans evading binary segmentation of Tb microstructure, while accounting for bone microstructural distribution. First, the tibial axis in a CT scan was aligned with the FE loading axis. FE cubic mesh elements were modeled using image voxels, and CT intensity values were calibrated to ash density defining mechanical properties at individual elements. For FEA of an upright volume of interest (VOI), the bottom surface was fixed, and a constant displacement was applied at each vertex on the top surface simulating different loading conditions. The method was implemented and optimized using the ANSYS software. CT‐derived computational modulus values were repeat scan reproducible (intraclass correlation coefficient [ICC] ≥ 0.97) and highly correlated (r ≥ 0.86) with the micro‐CT (μCT)‐derived values. FEA‐derived von Mises stresses over the segmented Tb microregion were significantly higher (p < 1 × 10−11) than that over the marrow space. In vivo results showed that both shear and compressive modulus for males were higher (p < 0.01) than for females. Effect sizes for different modulus measures between males and females were moderate‐to‐high (≥0.55) and reduced to small‐to‐negligible (<0.40) when adjusted for pure lean mass. Among body size and composition attributes, pure lean mass and height showed highest (r ∈ [0.45 0.56]) and lowest (r ∈ [0.25 0.39]) linear correlation, respectively, with FE‐derived modulus measures. In summary, CT‐based nonlinear FEA provides an effective surrogate measure of Tb microstructural stiffness, and the relaxation of binary segmentation will extend the scope for FEA in human studies using in vivo imaging at relatively low‐resolution. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Indranil Guha
- Department of Electrical and Computer Engineering University of Iowa Iowa City IA USA
| | - Xialiou Zhang
- Department of Electrical and Computer Engineering University of Iowa Iowa City IA USA
| | - Chamith S. Rajapakse
- Departments of Radiology and Orthopedic Surgery University of Pennsylvania PA USA
| | | | - Gregory Chang
- Department of Radiology New York University Grossman School of Medicine NY USA
| | - Kathleen F. Janz
- Department of Health and Human Physiology University of Iowa Iowa City IA USA
| | - James C. Torner
- Department of Epidemiology University of Iowa Iowa City IA USA
| | - Steven M. Levy
- Department of Epidemiology University of Iowa Iowa City IA USA
- Department of Preventive and Community Dentistry University of Iowa Iowa City IA USA
| | - Punam K. Saha
- Department of Electrical and Computer Engineering University of Iowa Iowa City IA USA
- Department of Radiology University of Iowa Iowa City IA USA
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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: 0] [Impact Index Per Article: 0] [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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Soldati E, Pithioux M, Guenoun D, Bendahan D, Vicente J. Assessment of Bone Microarchitecture in Fresh Cadaveric Human Femurs: What Could Be the Clinical Relevance of Ultra-High Field MRI. Diagnostics (Basel) 2022; 12:diagnostics12020439. [PMID: 35204529 PMCID: PMC8870786 DOI: 10.3390/diagnostics12020439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/27/2022] [Accepted: 02/03/2022] [Indexed: 11/16/2022] Open
Abstract
MRI could be applied for bone microarchitecture assessment; however, this technique is still suffering from low resolution compared to the trabecular dimension. A clear comparative analysis between MRI and X-ray microcomputed tomography (μCT) regarding microarchitecture metrics is still lacking. In this study, we performed a comparative analysis between μCT and 7T MRI with the aim of assessing the image resolution effect on the accuracy of microarchitecture metrics. We also addressed the issue of air bubble artifacts in cadaveric bones. Three fresh cadaveric femur heads were scanned using 7T MRI and µCT at high resolution (0.051 mm). Samples were submitted to a vacuum procedure combined with vibration to reduce the volume of air bubbles. Trabecular interconnectivity, a new metric, and conventional histomorphometric parameters were quantified using MR images and compared to those derived from µCT at full resolution and downsized resolutions (0.102 and 0.153 mm). Correlations between bone morphology and mineral density (BMD) were evaluated. Air bubbles were reduced by 99.8% in 30 min, leaving partial volume effects as the only source of bias. Morphological parameters quantified with 7T MRI were not statistically different (p > 0.01) to those computed from μCT images, with error up to 8% for both bone volume fraction and trabecular spacing. No linear correlation was found between BMD and all morphological parameters except trabecular interconnectivity (R2 = 0.69 for 7T MRI-BMD). These results strongly suggest that 7T MRI could be of interest for in vivo bone microarchitecture assessment, providing additional information about bone health and quality.
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Affiliation(s)
- Enrico Soldati
- Aix Marseille Univ, CNRS, IUSTI, 13453 Marseille, France;
- Aix Marseille Univ, CNRS, CRMBM, 13385 Marseille, France;
- Aix Marseille Univ, CNRS, ISM, 13288 Marseille, France; (M.P.); (D.G.)
- Correspondence:
| | - Martine Pithioux
- Aix Marseille Univ, CNRS, ISM, 13288 Marseille, France; (M.P.); (D.G.)
- Aix Marseille Univ, APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Department of Orthopaedics and Traumatology, 13274 Marseille, France
| | - Daphne Guenoun
- Aix Marseille Univ, CNRS, ISM, 13288 Marseille, France; (M.P.); (D.G.)
- Aix Marseille Univ, APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Department of Radiology, 13274 Marseille, France
| | - David Bendahan
- Aix Marseille Univ, CNRS, CRMBM, 13385 Marseille, France;
| | - Jerome Vicente
- Aix Marseille Univ, CNRS, IUSTI, 13453 Marseille, France;
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Yang L, Chen C, Zhang Z, Wei X. Diagnosis of Bone Mineral Density Based on Backscattering Resonance Phenomenon Using Coregistered Functional Laser Photoacoustic and Ultrasonic Probes. SENSORS (BASEL, SWITZERLAND) 2021; 21:8243. [PMID: 34960334 PMCID: PMC8706256 DOI: 10.3390/s21248243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/26/2021] [Accepted: 12/06/2021] [Indexed: 12/05/2022]
Abstract
Dual-energy X-ray absorptiometry (DXA) machines based on bone mineral density (BMD) represent the gold standard for osteoporosis diagnosis and assessment of fracture risk, but bone strength and toughness are strongly correlated with bone collagen content (CC). Early detection of osteoporosis combined with BMD and CC will provide improved predictability for avoiding fracture risk. The backscattering resonance (BR) phenomenon is present in both ultrasound (US) and photoacoustic (PA) signal transmissions through bone, and the peak frequencies of BR can be changed with BM and CC. This phenomenon can be explained by the formation of standing waves within the pores. Simulations were then conducted for the same bone µCT images and the resulting resonance frequencies were found to match those predicted using the standing wave hypothesis. Experiments were performed on the same bone sample using an 808 nm wavelength laser as the PA source and 3.5 MHz ultrasonic transducer as the US source. The backscattering resonance effect was observed in the transmitted waves. These results verify our hypothesis that the backscattering resonance phenomenon is present in both US and PA signal transmissions and can be explained using the standing waves model, which will provide a suitable method for the early detection of osteoporosis.
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Affiliation(s)
- Lifeng Yang
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (C.C.); (Z.Z.); (X.W.)
- Optoelectronic Imaging and Biophotonics Laboratory, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Chulin Chen
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (C.C.); (Z.Z.); (X.W.)
| | - Zhaojiang Zhang
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (C.C.); (Z.Z.); (X.W.)
| | - Xin Wei
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China; (C.C.); (Z.Z.); (X.W.)
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12
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Ruderman I, Rajapakse CS, Xu W, Tang S, Robertson PL, Toussaint ND. Changes in bone microarchitecture following parathyroidectomy in patients with secondary hyperparathyroidism. Bone Rep 2021; 15:101120. [PMID: 34485631 PMCID: PMC8406147 DOI: 10.1016/j.bonr.2021.101120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 08/04/2021] [Accepted: 08/18/2021] [Indexed: 11/16/2022] Open
Abstract
Background Secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD) has a significant effect on bone, affecting both trabecular and cortical compartments. Although parathyroidectomy results in biochemical improvement in mineral metabolism, changes in bone microarchitecture as evaluated by high-resolution imaging modalities are not known. Magnetic resonance imaging (MRI) provides in-depth three-dimensional assessment of bone microarchitecture, as well as determination of mechanical bone strength determined by finite element analysis (FEA). Methods We conducted a single-centre longitudinal study to evaluate changes in bone microarchitecture with MRI in patients with SHPT undergoing parathyroidectomy. MRI was performed at the distal tibia at baseline (time of parathyroidectomy) and at least 12 months following surgery. Trabecular and cortical topological parameters as well as bone mechanical competence using FEA were assessed. Results Fifteen patients with CKD (12 male, 3 female) underwent both MRI scans at the time of surgery and at least 12 months post-surgery. At baseline, 13 patients were on dialysis, one had a functioning kidney transplant, and one was pre-dialysis with stage 5 CKD. Seven patients received a kidney transplant following parathyroidectomy prior to follow-up MRI. MRI parameters in patients at follow up were consistent with loss in trabecular and cortical bone thickness (p = 0.006 and 0.03 respectively). Patients who underwent a kidney transplant in the follow-up period had reduction in trabecular thickness (p = 0.05), whereas those who continued on dialysis had reduction in cortical thickness (p = 0.04) and mechanical bone strength on FEA (p = 0.03). Conclusion Patients with severe SHPT requiring parathyroidectomy have persistent changes in bone microarchitecture at least 12 months following surgery with evidence of ongoing decline in trabecular and cortical thickness.
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Affiliation(s)
- Irene Ruderman
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Chamith S Rajapakse
- Departments of Radiology and Orthopaedic Surgery, University of Pennsylvania, PA, USA
| | - Winnie Xu
- Departments of Radiology and Orthopaedic Surgery, University of Pennsylvania, PA, USA
| | - Sisi Tang
- Departments of Radiology and Orthopaedic Surgery, University of Pennsylvania, PA, USA
| | - Patricia L Robertson
- Department of Radiology, The Royal Melbourne Hospital and The University of Melbourne, Parkville, Victoria, Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
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13
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Ayubcha C, Raynor WY, Borja AJ, Seraj SM, Rojulpote C, Werner TJ, Revheim ME, Rajapakse CS, Alavi A. Magnetic resonance imaging-based partial volume-corrected 18F-sodium fluoride positron emission tomography in the femoral neck. Nucl Med Commun 2021; 42:416-420. [PMID: 33306627 DOI: 10.1097/mnm.0000000000001344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES 18F-sodium fluoride (NaF) is a radiotracer used in PET that reflects calcium metabolism and osteoblastic activity. In this study, we assessed the construct validity of a novel application of global assessment to measure NaF uptake in the femoral neck as a method of evaluating physiologic changes in osteoblastic metabolism with age. METHODS Whole-body NaF-PET/computed tomography (CT) images and MRI of 24 male patients with a history of nonmetastatic prostate cancer between the ages of 36 and 82 years (67.8 ± 9.6) were analyzed. A region of interest delineated the entire femoral neck on the PET/CT image to determine the mean standardized uptake value (SUVmean). Correction for the partial volume effect was performed by measuring the volume of inert yellow bone marrow by MRI segmentation. Multiple linear regression was used to assess the relationship of uptake with age and body weight. RESULTS The SUVmean with and without partial volume correction decreased with respect to age (P = 0.001 and P = 0.002, respectively). Body weight was not significantly related to any measured PET parameter. CONCLUSION Our results support the use of global NaF uptake with magnetic resonance-derived partial volume correction in the femoral neck. Because osteoblastic metabolism is known to decrease with normal aging, the observed decrease in NaF uptake constitutes evidence for convergent validity, indicating that the proposed methodology likely reflects systemic osteoblastic activity. Future studies of this methodology are warranted in other instances of varying osteoblastic activity such as in metabolic bone diseases and for the evaluation of therapy targeting osteoblastic metabolism.
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Affiliation(s)
- Cyrus Ayubcha
- Department of Radiology, Hospital of the University of Pennsylvania
| | - William Y Raynor
- Department of Radiology, Hospital of the University of Pennsylvania
- Department of Medicine, Drexel University College of Medicine
| | - Austin J Borja
- Department of Radiology, Hospital of the University of Pennsylvania
- Department of Orthopedic Surgery, Hospital of the University of Pennsylvania
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Siavash M Seraj
- Department of Radiology, Hospital of the University of Pennsylvania
| | | | - Thomas J Werner
- Department of Radiology, Hospital of the University of Pennsylvania
| | - Mona-Elisabeth Revheim
- Department of Radiology, Hospital of the University of Pennsylvania
- Division for Radiology and Nuclear Medicine, Oslo University Hospital
- Department of Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Chamith S Rajapakse
- Department of Radiology, Hospital of the University of Pennsylvania
- Department of Orthopedic Surgery, Hospital of the University of Pennsylvania
| | - Abass Alavi
- Department of Radiology, Hospital of the University of Pennsylvania
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14
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Rajapakse CS, Johncola AJ, Batzdorf AS, Jones BC, Al Mukaddam M, Sexton K, Shults J, Leonard MB, Snyder PJ, Wehrli FW. Effect of Low-Intensity Vibration on Bone Strength, Microstructure, and Adiposity in Pre-Osteoporotic Postmenopausal Women: A Randomized Placebo-Controlled Trial. J Bone Miner Res 2021; 36:673-684. [PMID: 33314313 DOI: 10.1002/jbmr.4229] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 11/21/2020] [Accepted: 11/27/2020] [Indexed: 12/31/2022]
Abstract
There has been evidence that cyclical mechanical stimulation may be osteogenic, thus providing opportunities for nonpharmacological treatment of degenerative bone disease. Here, we applied this technology to a cohort of postmenopausal women with varying bone mineral density (BMD) T-scores at the total hip (-0.524 ± 0.843) and spine (-0.795 ± 1.03) to examine the response to intervention after 1 year of daily treatment with 10 minutes of vibration therapy in a randomized double-blinded trial. The device operates either in an active mode (30 Hz and 0.3 g) or placebo. Primary endpoints were changes in bone stiffness at the distal tibia and marrow adiposity of the vertebrae, based on 3 Tesla high-resolution MRI and spectroscopic imaging, respectively. Secondary outcome variables included distal tibial trabecular microstructural parameters and vertebral deformity determined by MRI, volumetric and areal bone densities derived using peripheral quantitative computed tomography (pQCT) of the tibia, and dual-energy X-ray absorptiometry (DXA)-based BMD of the hip and spine. Device adherence was 83% in the active group (n = 42) and 86% in the placebo group (n = 38) and did not differ between groups (p = .7). The mean 12-month changes in tibial stiffness in the treatment group and placebo group were +1.31 ± 6.05% and -2.55 ± 3.90%, respectively (group difference 3.86%, p = .0096). In the active group, marrow fat fraction significantly decreased after 12 months of intervention (p = .0003), whereas no significant change was observed in the placebo group (p = .7; group difference -1.59%, p = .029). Mean differences of the changes in trabecular bone volume fraction (p = .048) and erosion index (p = .044) were also significant, as was pQCT-derived trabecular volumetric BMD (vBMD; p = .016) at the tibia. The data are commensurate with the hypothesis that vibration therapy is protective against loss in mechanical strength and, further, that the intervention minimizes the shift from the osteoblastic to the adipocytic lineage of mesenchymal stem cells. © 2020 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Chamith S Rajapakse
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA.,Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Alyssa J Johncola
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Brandon C Jones
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Mona Al Mukaddam
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA.,Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kelly Sexton
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Justine Shults
- Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania, Philadelphia, PA, USA
| | - Mary B Leonard
- Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA.,Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Peter J Snyder
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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15
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Soldati E, Rossi F, Vicente J, Guenoun D, Pithioux M, Iotti S, Malucelli E, Bendahan D. Survey of MRI Usefulness for the Clinical Assessment of Bone Microstructure. Int J Mol Sci 2021; 22:2509. [PMID: 33801539 PMCID: PMC7958958 DOI: 10.3390/ijms22052509] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/21/2021] [Accepted: 02/25/2021] [Indexed: 12/12/2022] Open
Abstract
Bone microarchitecture has been shown to provide useful information regarding the evaluation of skeleton quality with an added value to areal bone mineral density, which can be used for the diagnosis of several bone diseases. Bone mineral density estimated from dual-energy X-ray absorptiometry (DXA) has shown to be a limited tool to identify patients' risk stratification and therapy delivery. Magnetic resonance imaging (MRI) has been proposed as another technique to assess bone quality and fracture risk by evaluating the bone structure and microarchitecture. To date, MRI is the only completely non-invasive and non-ionizing imaging modality that can assess both cortical and trabecular bone in vivo. In this review article, we reported a survey regarding the clinically relevant information MRI could provide for the assessment of the inner trabecular morphology of different bone segments. The last section will be devoted to the upcoming MRI applications (MR spectroscopy and chemical shift encoding MRI, solid state MRI and quantitative susceptibility mapping), which could provide additional biomarkers for the assessment of bone microarchitecture.
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Affiliation(s)
- Enrico Soldati
- CRMBM, CNRS, Aix Marseille University, 13385 Marseille, France;
- IUSTI, CNRS, Aix Marseille University, 13013 Marseille, France;
- ISM, CNRS, Aix Marseille University, 13288 Marseille, France; (D.G.); (M.P.)
| | - Francesca Rossi
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy; (F.R.); (S.I.); (E.M.)
| | - Jerome Vicente
- IUSTI, CNRS, Aix Marseille University, 13013 Marseille, France;
| | - Daphne Guenoun
- ISM, CNRS, Aix Marseille University, 13288 Marseille, France; (D.G.); (M.P.)
- Department of Radiology, Institute for Locomotion, Saint-Marguerite Hospital, ISM, CNRS, APHM, Aix Marseille University, 13274 Marseille, France
| | - Martine Pithioux
- ISM, CNRS, Aix Marseille University, 13288 Marseille, France; (D.G.); (M.P.)
- Department of Orthopedics and Traumatology, Institute for Locomotion, Saint-Marguerite Hospital, ISM, CNRS, APHM, Aix Marseille University, 13274 Marseille, France
| | - Stefano Iotti
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy; (F.R.); (S.I.); (E.M.)
- National Institute of Biostructures and Biosystems, 00136 Rome, Italy
| | - Emil Malucelli
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy; (F.R.); (S.I.); (E.M.)
| | - David Bendahan
- CRMBM, CNRS, Aix Marseille University, 13385 Marseille, France;
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16
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Jones BC, Jia S, Lee H, Feng A, Shetye SS, Batzdorf A, Shapira N, Noël PB, Pleshko N, Rajapakse CS. MRI-derived porosity index is associated with whole-bone stiffness and mineral density in human cadaveric femora. Bone 2021; 143:115774. [PMID: 33271401 PMCID: PMC7769997 DOI: 10.1016/j.bone.2020.115774] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 01/13/2023]
Abstract
Ultrashort echo time (UTE) magnetic resonance imaging (MRI) measures proton signals in cortical bone from two distinct water pools, bound water, or water that is tightly bound to bone matrix, and pore water, or water that is freely moving in the pore spaces in bone. By isolating the signal contribution from the pore water pool, UTE biomarkers can directly quantify cortical bone porosity in vivo. The Porosity Index (PI) is one non-invasive, clinically viable UTE-derived technique that has shown strong associations in the tibia with μCT porosity and other UTE measures of bone water. However, the efficacy of the PI biomarker has never been examined in the proximal femur, which is the site of the most catastrophic osteoporotic fractures. Additionally, the loads experienced during a sideways fall are complex and the femoral neck is difficult to image with UTE, so the usefulness of the PI in the femur was unknown. Therefore, the aim of this study was to examine the relationships between the PI measure in the proximal cortical shaft of human cadaveric femora specimens compared to (1) QCT-derived bone mineral density (BMD) and (2) whole bone stiffness obtained from mechanical testing mimicking a sideways fall. Fifteen fresh, frozen whole cadaveric femora specimens (age 72.1 ± 15.0 years old, 10 male, 5 female) were scanned on a clinical 3-T MRI using a dual-echo UTE sequence. Specimens were then scanned on a clinical CT scanner to measure volumetric BMD (vBMD) and then non-destructively mechanically tested in a sideways fall configuration. The PI in the cortical shaft demonstrated strong correlations with bone stiffness (r = -0.82, P = 0.0014), CT-derived vBMD (r = -0.64, P = 0.0149), and with average cortical thickness (r = -0.60, P = 0.0180). Furthermore, a hierarchical regression showed that PI was a strong predictor of bone stiffness which was independent of the other parameters. The findings from this study validate the MRI-derived porosity index as a useful measure of whole-bone mechanical integrity and stiffness.
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Affiliation(s)
- Brandon C Jones
- Department of Radiology, University of Pennsylvania, United States of America; Department of Bioengineering, University of Pennsylvania, United States of America.
| | - Shaowei Jia
- Department of Radiology, University of Pennsylvania, United States of America; School of Biomedical Science and Medical Engineering, Beihang University, China
| | - Hyunyeol Lee
- Department of Radiology, University of Pennsylvania, United States of America
| | - Anna Feng
- Department of Bioengineering, University of Pennsylvania, United States of America
| | - Snehal S Shetye
- Department of Orthopaedic Surgery, University of Pennsylvania, United States of America
| | - Alexandra Batzdorf
- Department of Radiology, University of Pennsylvania, United States of America
| | - Nadav Shapira
- Department of Radiology, University of Pennsylvania, United States of America
| | - Peter B Noël
- Department of Radiology, University of Pennsylvania, United States of America
| | - Nancy Pleshko
- Department of Bioengineering, Temple University, United States of America
| | - Chamith S Rajapakse
- Department of Radiology, University of Pennsylvania, United States of America; Department of Orthopaedic Surgery, University of Pennsylvania, United States of America
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17
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Jerban S, Ma Y, Wei Z, Jang H, Chang EY, Du J. Quantitative Magnetic Resonance Imaging of Cortical and Trabecular Bone. Semin Musculoskelet Radiol 2020; 24:386-401. [PMID: 32992367 DOI: 10.1055/s-0040-1710355] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Bone is a composite material consisting of mineral, organic matrix, and water. Water in bone can be categorized as bound water (BW), which is bound to bone mineral and organic matrix, or as pore water (PW), which resides in Haversian canals as well as in lacunae and canaliculi. Bone is generally classified into two types: cortical bone and trabecular bone. Cortical bone is much denser than trabecular bone that is surrounded by marrow and fat. Magnetic resonance (MR) imaging has been increasingly used for noninvasive assessment of both cortical bone and trabecular bone. Bone typically appears as a signal void with conventional MR sequences because of its short T2*. Ultrashort echo time (UTE) sequences with echo times 100 to 1,000 times shorter than those of conventional sequences allow direct imaging of BW and PW in bone. This article summarizes several quantitative MR techniques recently developed for bone evaluation. Specifically, we discuss the use of UTE and adiabatic inversion recovery prepared UTE sequences to quantify BW and PW, UTE magnetization transfer sequences to quantify collagen backbone protons, UTE quantitative susceptibility mapping sequences to assess bone mineral, and conventional sequences for high-resolution imaging of PW as well as the evaluation of trabecular bone architecture.
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Affiliation(s)
- Saeed Jerban
- Department of Radiology, University of California, San Diego, California
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, California
| | - Zhao Wei
- Department of Radiology, University of California, San Diego, California
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, California
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, California.,Research Service, Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Jiang Du
- Department of Radiology, University of California, San Diego, California
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18
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Ruderman I, Rajapakse CS, Opperman A, Robertson PL, Masterson R, Tiong MK, Toussaint ND. Bone microarchitecture in patients undergoing parathyroidectomy for management of secondary hyperparathyroidism. Bone Rep 2020; 13:100297. [PMID: 32760761 PMCID: PMC7393533 DOI: 10.1016/j.bonr.2020.100297] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/03/2020] [Accepted: 07/06/2020] [Indexed: 12/14/2022] Open
Abstract
Background Secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD) leads to complex bone disease, affecting both trabecular and cortical bone, and increased fracture risk. Optimal assessment of bone in patients with CKD is yet to be determined. High-resolution magnetic resonance imaging (MRI) can provide three-dimensional assessment of bone microarchitecture, as well as determination of mechanical strength with finite element analysis (FEA). Methods We conducted a single-centre, cross-sectional study to determine bone microarchitecture with MRI in CKD patients with SHPT undergoing parathyroidectomy. Within two weeks of surgery, MRI was performed at the distal tibia and biochemical markers of SHPT (parathyroid hormone [PTH] and alkaline phosphatase [ALP]) were collected. Trabecular and cortical topological parameters as well as bone mechanical competence using FEA were assessed. Correlation of MRI findings of bone was made with biochemical markers. Results Twenty patients with CKD (15 male, 5 female) underwent MRI at the time of parathyroidectomy (16 on dialysis, 3 with functioning kidney transplant, one pre-dialysis with CKD stage 5). Median PTH at the time of surgery was 138.5 pmol/L [39.6–186.7 pmol/L]. MRI parameters in patients were consistent with trabecular deterioration, with erosion index (EI) 1.01 ± 0.3, and trabecular bone volume (BV/TV) 10.8 ± 2.9%, as well as poor trabecular network integrity with surface-to-curve ratio (S/C) 5.4 ± 2.3. There was also evidence of reduced cortical thickness, with CTh 2.698 ± 0.630 mm, and FEA demonstrated overall poor bone mechanical strength with mean elastic modulus of 2.07 ± 0.44. Conclusion Patients with severe SHPT requiring parathyroidectomy have evidence of significant changes in bone microarchitecture with trabecular deterioration, low trabecular and cortical bone volume, and reduced mechanical competence of bone.
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Affiliation(s)
- Irene Ruderman
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Chamith S Rajapakse
- Departments of Radiology and Orthopaedic Surgery, University of Pennsylvania, PA, USA
| | - Angelica Opperman
- Departments of Radiology and Orthopaedic Surgery, University of Pennsylvania, PA, USA
| | - Patricia L Robertson
- Department of Radiology, The Royal Melbourne Hospital and The University of Melbourne, Parkville, Victoria, Australia
| | - Rosemary Masterson
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Mark K Tiong
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
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19
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Rajapakse CS, Farid AR, Kargilis DC, Jones BC, Lee JS, Johncola AJ, Batzdorf AS, Shetye SS, Hast MW, Chang G. MRI-based assessment of proximal femur strength compared to mechanical testing. Bone 2020; 133:115227. [PMID: 31926345 PMCID: PMC7096175 DOI: 10.1016/j.bone.2020.115227] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/02/2020] [Accepted: 01/07/2020] [Indexed: 12/14/2022]
Abstract
Half of the women who sustain a hip fracture would not qualify for osteoporosis treatment based on current DXA-estimated bone mineral density criteria. Therefore, a better approach is needed to determine if an individual is at risk of hip fracture from a fall. The objective of this study was to determine the association between radiation-free MRI-derived bone strength and strain simulations compared to results from direct mechanical testing of cadaveric femora. Imaging was conducted on a 3-Tesla MRI scanner using two sequences: one balanced steady-state free precession sequence with 300 μm isotropic voxel size and one spoiled gradient echo with anisotropic voxel size of 234 × 234 × 1500 μm. Femora were dissected free of soft-tissue and 4350-ohm strain-gauges were securely applied to surfaces at the femoral shaft, inferior neck, greater trochanter, and superior neck. Cadavers were mechanically tested with a hydraulic universal test frame to simulate loading in a sideways fall orientation. Sideways fall forces were simulated on MRI-based finite element meshes and bone stiffness, failure force, and force for plastic deformation were computed. Simulated bone strength metrics from the 300 μm isotropic sequence showed strong agreement with experimentally obtained values of bone strength, with stiffness (r = 0.88, p = 0.0002), plastic deformation point (r = 0.89, p < 0.0001), and failure force (r = 0.92, p < 0.0001). The anisotropic sequence showed similar trends for stiffness, plastic deformation point, and failure force (r = 0.68, 0.70, 0.84; p = 0.02, 0.01, 0.0006, respectively). Surface strain-gauge measurements showed moderate to strong agreement with simulated magnitude strain values at the greater trochanter, superior neck, and inferior neck (r = -0.97, -0.86, 0.80; p ≤0.0001, 0.003, 0.03, respectively). The findings from this study support the use of MRI-based FE analysis of the hip to reliably predict the mechanical competence of the human femur in clinical settings.
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Affiliation(s)
- Chamith S Rajapakse
- Department of Radiology, University of Pennsylvania, United States of America; Department of Orthopaedic Surgery, University of Pennsylvania, United States of America.
| | - Alexander R Farid
- Department of Radiology, University of Pennsylvania, United States of America
| | - Daniel C Kargilis
- Department of Radiology, University of Pennsylvania, United States of America
| | - Brandon C Jones
- Department of Radiology, University of Pennsylvania, United States of America
| | - Jae S Lee
- Department of Radiology, University of Pennsylvania, United States of America
| | - Alyssa J Johncola
- Department of Radiology, University of Pennsylvania, United States of America
| | | | - Snehal S Shetye
- Department of Orthopaedic Surgery, University of Pennsylvania, United States of America
| | - Michael W Hast
- Department of Orthopaedic Surgery, University of Pennsylvania, United States of America
| | - Gregory Chang
- Department of Radiology, New York University, United States of America
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20
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Jerban S, Chang DG, Ma Y, Jang H, Chang EY, Du J. An Update in Qualitative Imaging of Bone Using Ultrashort Echo Time Magnetic Resonance. Front Endocrinol (Lausanne) 2020; 11:555756. [PMID: 33117275 PMCID: PMC7551122 DOI: 10.3389/fendo.2020.555756] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 09/11/2020] [Indexed: 12/31/2022] Open
Abstract
Bone is comprised of mineral, collagenous organic matrix, and water. X-ray-based techniques are the standard approach for bone evaluation in clinics, but they are unable to detect the organic matrix and water components in bone. Magnetic resonance imaging (MRI) is being used increasingly for bone evaluation. While MRI can non-invasively assess the proton pools in soft tissues, cortical bone typically appears as a signal void with clinical MR techniques because of its short T2*. New MRI techniques have been recently developed to image bone while avoiding the ionizing radiation present in x-ray-based methods. Qualitative bone imaging can be achieved using ultrashort echo time (UTE), single inversion recovery UTE (IR-UTE), dual-inversion recovery UTE (Dual-IR-UTE), double-inversion recovery UTE (Double-IR-UTE), and zero echo time (ZTE) sequences. The contrast mechanisms as well as the advantages and disadvantages of each technique are discussed.
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Affiliation(s)
- Saeed Jerban
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Douglas G. Chang
- Departments of Orthopaedic Surgery, University of California, San Diego, San Diego, CA, United States
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Eric Y. Chang
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, United States
| | - Jiang Du
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- *Correspondence: Jiang Du,
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Alcântara ACS, Assis I, Prada D, Mehle K, Schwan S, Costa-Paiva L, Skaf MS, Wrobel LC, Sollero P. Patient-Specific Bone Multiscale Modelling, Fracture Simulation and Risk Analysis-A Survey. MATERIALS (BASEL, SWITZERLAND) 2019; 13:E106. [PMID: 31878356 PMCID: PMC6981613 DOI: 10.3390/ma13010106] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 12/26/2022]
Abstract
This paper provides a starting point for researchers and practitioners from biology, medicine, physics and engineering who can benefit from an up-to-date literature survey on patient-specific bone fracture modelling, simulation and risk analysis. This survey hints at a framework for devising realistic patient-specific bone fracture simulations. This paper has 18 sections: Section 1 presents the main interested parties; Section 2 explains the organzation of the text; Section 3 motivates further work on patient-specific bone fracture simulation; Section 4 motivates this survey; Section 5 concerns the collection of bibliographical references; Section 6 motivates the physico-mathematical approach to bone fracture; Section 7 presents the modelling of bone as a continuum; Section 8 categorizes the surveyed literature into a continuum mechanics framework; Section 9 concerns the computational modelling of bone geometry; Section 10 concerns the estimation of bone mechanical properties; Section 11 concerns the selection of boundary conditions representative of bone trauma; Section 12 concerns bone fracture simulation; Section 13 presents the multiscale structure of bone; Section 14 concerns the multiscale mathematical modelling of bone; Section 15 concerns the experimental validation of bone fracture simulations; Section 16 concerns bone fracture risk assessment. Lastly, glossaries for symbols, acronyms, and physico-mathematical terms are provided.
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Affiliation(s)
- Amadeus C. S. Alcântara
- Department of Computational Mechanics, School of Mechanical Engineering, University of Campinas—UNICAMP, Campinas, Sao Paulo 13083-860, Brazil; (A.C.S.A.); (D.P.)
| | - Israel Assis
- Department of Integrated Systems, School of Mechanical Engineering, University of Campinas—UNICAMP, Campinas, Sao Paulo 13083-860, Brazil;
| | - Daniel Prada
- Department of Computational Mechanics, School of Mechanical Engineering, University of Campinas—UNICAMP, Campinas, Sao Paulo 13083-860, Brazil; (A.C.S.A.); (D.P.)
| | - Konrad Mehle
- Department of Engineering and Natural Sciences, University of Applied Sciences Merseburg, 06217 Merseburg, Germany;
| | - Stefan Schwan
- Fraunhofer Institute for Microstructure of Materials and Systems IMWS, 06120 Halle/Saale, Germany;
| | - Lúcia Costa-Paiva
- Department of Obstetrics and Gynecology, School of Medical Sciences, University of Campinas—UNICAMP, Campinas, Sao Paulo 13083-887, Brazil;
| | - Munir S. Skaf
- Institute of Chemistry and Center for Computing in Engineering and Sciences, University of Campinas—UNICAMP, Campinas, Sao Paulo 13083-860, Brazil;
| | - Luiz C. Wrobel
- Institute of Materials and Manufacturing, Brunel University London, Uxbridge UB8 3PH, UK;
- Department of Civil and Environmental Engineering, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro 22451-900, Brazil
| | - Paulo Sollero
- Department of Computational Mechanics, School of Mechanical Engineering, University of Campinas—UNICAMP, Campinas, Sao Paulo 13083-860, Brazil; (A.C.S.A.); (D.P.)
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Leonard MB, Wehrli FW, Ziolkowski SL, Billig E, Long J, Nickolas TL, Magland JF, Nihtianova S, Zemel BS, Herskovitz R, Rajapakse CS. A multi-imaging modality study of bone density, bone structure and the muscle - bone unit in end-stage renal disease. Bone 2019; 127:271-279. [PMID: 31158505 DOI: 10.1016/j.bone.2019.05.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 05/16/2019] [Accepted: 05/16/2019] [Indexed: 01/10/2023]
Abstract
End stage renal disease (ESRD) is associated with sarcopenia and skeletal fragility. The objectives of this cross-sectional study were to (1) characterize body composition, bone mineral density (BMD) and bone structure in hemodialysis patients compared with controls, (2) assess whether DXA areal BMD (aBMD) correlates with peripheral quantitative CT (pQCT) measures of volumetric BMD (vBMD), cortical dimensions and MRI measures of trabecular microarchitecture, and (3) determine the magnitude of bone deficits in ESRD after adjustment for muscle mass. Thirty ESRD participants, ages 25 to 64 years, were compared with 403 controls for DXA and pQCT outcomes and 104 controls for MRI outcomes; results were expressed as race- and sex- specific Z-scores relative to age. DXA appendicular lean mass index (ALMI kg/m2) and total hip, femoral neck, ultradistal and 1/3rd radius aBMD were significantly lower in ESRD, vs. controls (all p < 0.01). pQCT trabecular vBMD (p < 0.01), cortical vBMD (p < 0.001) and cortical thickness (due to a greater endosteal circumference, p < 0.02) and MRI measures of trabecular number, trabecular thickness, and whole bone stiffness were lower (all p < 0.01) in ESRD, vs. controls. ALMI was positively associated with total hip, femoral neck, ultradistal radius and 1/3rd radius aBMD and with tibia cortical thickness (R = 0.46 to 0.64). Adjustment for ALMI significantly attenuated bone deficits at these sites: e.g. mean femoral neck aBMD was 0.79 SD lower in ESRD, compared with controls and this was attenuated to 0.33 with adjustment for ALMI. In multivariate models within the dialysis participants, pQCT trabecular vBMD and cortical area Z-scores were significant and independently (all p < 0.02) associated with DXA femoral neck, total hip, and ultradistal radius aBMD Z-scores. Cortical vBMD (p = 0.01) and cortical area (p < 0.001) Z-scores were significantly and independently associated with 1/3rd radius areal aBMD Z-scores (R2 = 0.62). These data demonstrate that DXA aBMD captures deficits in trabecular and cortical vBMD and cortical area. The strong associations with ALMI, as an index of skeletal muscle, highlight the importance of considering the role of sarcopenia in skeletal fragility in patients with ESRD.
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Affiliation(s)
- Mary B Leonard
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, United States of America; Department of Medicine, Stanford University School of Medicine, Stanford, CA, United States of America.
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Susan L Ziolkowski
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, United States of America
| | - Erica Billig
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Jin Long
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, United States of America
| | - Thomas L Nickolas
- Department of Medicine, Columbia University, New York, NY, United States of America
| | - Jeremy F Magland
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Snejana Nihtianova
- Susanne M. Glasscock School of Continuing Studies, Rice University, Houston, TX, United States of America
| | - Babette S Zemel
- Department of Pediatrics, The Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Rita Herskovitz
- Department of Pediatrics, The Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Chamith S Rajapakse
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States of America; Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States of America
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Rajapakse CS, Chang G. Micro-Finite Element Analysis of the Proximal Femur on the Basis of High-Resolution Magnetic Resonance Images. Curr Osteoporos Rep 2018; 16:657-664. [PMID: 30232586 PMCID: PMC6234089 DOI: 10.1007/s11914-018-0481-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
PURPOSE OF REVIEW Hip fractures have catastrophic consequences. The purpose of this article is to review recent developments in high-resolution magnetic resonance imaging (MRI)-guided finite element analysis (FEA) of the hip as a means to determine subject-specific bone strength. RECENT FINDINGS Despite the ability of DXA to predict hip fracture, the majority of fractures occur in patients who do not have BMD T scores less than - 2.5. Therefore, without other detection methods, these individuals go undetected and untreated. Of methods available to image the hip, MRI is currently the only one capable of depicting bone microstructure in vivo. Availability of microstructural MRI allows generation of patient-specific micro-finite element models that can be used to simulate real-life loading conditions and determine bone strength. MRI-based FEA enables radiation-free approach to assess hip fracture strength. With further validation, this technique could become a potential clinical tool in managing hip fracture risk.
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Affiliation(s)
- Chamith S Rajapakse
- Departments of Radiology and Orthopaedic Surgery, University of Pennsylvania, 3400 Spruce Street, 1 Founders Building, Philadelphia, PA, 19104, USA.
| | - Gregory Chang
- Department of Radiology, New York University, 426 1st Avenue, New York, NY, 10010, USA
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Rajapakse CS, Kobe EA, Batzdorf AS, Hast MW, Wehrli FW. Accuracy of MRI-based finite element assessment of distal tibia compared to mechanical testing. Bone 2018; 108:71-78. [PMID: 29278746 PMCID: PMC5803422 DOI: 10.1016/j.bone.2017.12.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/14/2017] [Accepted: 12/22/2017] [Indexed: 11/28/2022]
Abstract
High-resolution MRI-derived finite element analysis (FEA) has been used in translational research to estimate the mechanical competence of human bone. However, this method has yet to be validated adequately under in vivo imaging spatial resolution or signal-to-noise conditions. We therefore compared MRI-based metrics of bone strength to those obtained from direct, mechanical testing. The study was conducted on tibiae from 17 human donors (12 males and five females, aged 33 to 88years) with no medical history of conditions affecting bone mineral homeostasis. A 25mm segment from each distal tibia underwent MR imaging in a clinical 3-Tesla scanner using a fast large-angle spin-echo (FLASE) sequence at 0.137mm×0.137mm×0.410mm voxel size, in accordance with in vivo scanning protocol. The resulting high-resolution MR images were processed and used to generate bone volume fraction maps, which served as input for the micro-level FEA model. Simulated compression was applied to compute stiffness, yield strength, ultimate strength, modulus of resilience, and toughness, which were then compared to metrics obtained from mechanical testing. Moderate to strong positive correlations were found between computationally and experimentally derived values of stiffness (R2=0.77, p<0.0001), yield strength (R2=0.38, p=0.0082), ultimate strength (R2=0.40, p=0.0067), and resilience (R2=0.46, p=0.0026), but only a weak, albeit significant, correlation was found for toughness (R2=0.26, p=0.036). Furthermore, experimentally derived yield strength and ultimate strength were moderately correlated with MRI-derived stiffness (R2=0.48, p=0.0022 and R2=0.58, p=0.0004, respectively). These results suggest that high-resolution MRI-based finite element (FE) models are effective in assessing mechanical parameters of distal skeletal extremities.
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Affiliation(s)
- Chamith S Rajapakse
- Department of Radiology, University of Pennsylvania, United States; Department of Orthopaedic Surgery, University of Pennsylvania, United States.
| | - Elizabeth A Kobe
- Department of Radiology, University of Pennsylvania, United States
| | | | - Michael W Hast
- Department of Orthopaedic Surgery, University of Pennsylvania, United States
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania, United States
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Rajapakse CS, Leonard MB, Kobe EA, Slinger MA, Borges KA, Billig E, Rubin CT, Wehrli FW. The Efficacy of Low-intensity Vibration to Improve Bone Health in Patients with End-stage Renal Disease Is Highly Dependent on Compliance and Muscle Response. Acad Radiol 2017; 24:1332-1342. [PMID: 28652048 DOI: 10.1016/j.acra.2017.05.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/23/2017] [Indexed: 12/28/2022]
Abstract
RATIONAL AND OBJECTIVES Low intensity vibration (LIV) may represent a nondrug strategy to mitigate bone deficits in patients with end-stage renal disease. MATERIALS AND METHODS Thirty end-stage renal patients on maintenance hemodialysis were randomized to stand for 20 minutes each day on either an active or placebo LIV device. Analysis at baseline and completion of 6-month intervention included magnetic resonance imaging (tibia and fibula stiffness; trabecular thickness, number, separation, bone volume fraction, plate-to-rod ratio; and cortical bone porosity), dual-energy X-ray absorptiometry (hip and spine bone mineral density [BMD]), and peripheral quantitative computed tomography (tibia trabecular and cortical BMD; calf muscle cross-sectional area). RESULTS Intention-to-treat analysis did not show any significant changes in outcomes associated with LIV. Subjects using the active device and with greater than the median adherence (70%) demonstrated an increase in distal tibia stiffness (5.3%), trabecular number (1.7%), BMD (2.3%), and plate-to-rod ratio (6.5%), and a decrease in trabecular separation (-1.8%). Changes in calf muscle cross-sectional area were associated with changes in distal tibia stiffness (R = 0.85), trabecular bone volume/total volume (R = 0.91), number (R = 0.92), and separation (R = -0.94) in the active group but not in the placebo group. Baseline parathyroid hormone levels were positively associated with increased cortical bone porosity over the 6-month study period in the placebo group (R = 0.55) but not in the active group (R = 0.01). No changes were observed in the nondistal tibia locations for either group except a decrease in hip BMD in the placebo group (-1.7%). CONCLUSION Outcomes and adherence thresholds identified from this pilot study could guide future longitudinal studies involving vibration therapy.
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Chang G, Boone S, Martel D, Rajapakse CS, Hallyburton RS, Valko M, Honig S, Regatte RR. MRI assessment of bone structure and microarchitecture. J Magn Reson Imaging 2017; 46:323-337. [PMID: 28165650 PMCID: PMC5690546 DOI: 10.1002/jmri.25647] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 12/21/2016] [Indexed: 12/12/2022] Open
Abstract
Osteoporosis is a disease of weak bone and increased fracture risk caused by low bone mass and microarchitectural deterioration of bone tissue. The standard-of-care test used to diagnose osteoporosis, dual-energy x-ray absorptiometry (DXA) estimation of areal bone mineral density (BMD), has limitations as a tool to identify patients at risk for fracture and as a tool to monitor therapy response. Magnetic resonance imaging (MRI) assessment of bone structure and microarchitecture has been proposed as another method to assess bone quality and fracture risk in vivo. MRI is advantageous because it is noninvasive, does not require ionizing radiation, and can evaluate both cortical and trabecular bone. In this review article, we summarize and discuss research progress on MRI of bone structure and microarchitecture over the last decade, focusing on in vivo translational studies. Single-center, in vivo studies have provided some evidence for the added value of MRI as a biomarker of fracture risk or treatment response. Larger, prospective, multicenter studies are needed in the future to validate the results of these initial translational studies. LEVEL OF EVIDENCE 5 Technical Efficacy: Stage 5 J. MAGN. RESON. IMAGING 2017;46:323-337.
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Affiliation(s)
- Gregory Chang
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Sean Boone
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Dimitri Martel
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Chamith S Rajapakse
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Robert S Hallyburton
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Mitch Valko
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Stephen Honig
- Osteoporosis Center, Hospital for Joint Diseases, NYU Langone Medical Center, New York, New York, USA
| | - Ravinder R Regatte
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
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Abstract
PURPOSE OF REVIEW This paper seeks to evaluate and compare recent advances in the clinical assessment of the changes in bone mechanical properties that take place as a result of osteoporosis and other metabolic bone diseases and their treatments. RECENT FINDINGS In addition to the standard of DXA-based areal bone mineral density (aBMD), a variety of methods, including imaging-based structural measurements, finite element analysis (FEA)-based techniques, and alternate methods including ultrasound, bone biopsy, reference point indentation, and statistical shape and density modeling, have been developed which allow for reliable prediction of bone strength and fracture risk. These methods have also shown promise in the evaluation of treatment-induced changes in bone mechanical properties. Continued technological advances allowing for increasingly high-resolution imaging with low radiation dose, together with the expanding adoption of DXA-based predictions of bone structure and mechanics, as well as the increasing awareness of the importance of bone material properties in determining whole-bone mechanics, lead us to anticipate substantial future advances in this field.
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Affiliation(s)
- Chantal M J de Bakker
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA
| | - Wei-Ju Tseng
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA
| | - Yihan Li
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA
| | - Hongbo Zhao
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA
| | - X Sherry Liu
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA.
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Rajapakse CS, Hotca A, Newman BT, Ramme A, Vira S, Kobe EA, Miller R, Honig S, Chang G. Patient-specific Hip Fracture Strength Assessment with Microstructural MR Imaging-based Finite Element Modeling. Radiology 2016; 283:854-861. [PMID: 27918708 DOI: 10.1148/radiol.2016160874] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Purpose To describe a nonlinear finite element analysis method by using magnetic resonance (MR) images for the assessment of the mechanical competence of the hip and to demonstrate the reproducibility of the tool. Materials and Methods This prospective study received institutional review board approval and fully complied with HIPAA regulations for patient data. Written informed consent was obtained from all subjects. A nonlinear finite element analysis method was developed to estimate mechanical parameters that relate to hip fracture resistance by using MR images. Twenty-three women (mean age ± standard deviation, 61.7 years ± 13.8) were recruited from a single osteoporosis center. To thoroughly assess the reproducibility of the finite element method, three separate analyses were performed: a test-retest reproducibility analysis, where each of the first 13 subjects underwent MR imaging on three separate occasions to determine longitudinal variability, and an intra- and interoperator reproducibility analysis, where a single examination was performed in each of the next 10 subjects and four operators independently performed the analysis two times in each of the subjects. Reproducibility of parameters that reflect fracture resistance was assessed by using the intraclass correlation coefficient and the coefficient of variation. Results For test-retest reproducibility analysis and inter- and intraoperator analyses for proximal femur stiffness, yield strain, yield load, ultimate strain, ultimate load, resilience, and toughness in both stance and sideways-fall loading configurations each had an individual median coefficient of variation of less than 10%. Additionally, all measures had an intraclass correlation coefficient higher than 0.99. Conclusion This experiment demonstrates that the finite element analysis model can consistently and reliably provide fracture risk information on correctly segmented bone images. © RSNA, 2016 Online supplemental material is available for this article.
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Affiliation(s)
- Chamith S Rajapakse
- From the Departments of Radiology (C.S.R., B.T.N., E.A.K., R.M.) and Orthopaedic Surgery (C.S.R.), University of Pennsylvania, 3400 Spruce St, 1 Founders Building, Philadelphia, PA 19104; and Department of Radiology, Center for Biomedical Imaging (A.H., G.C.), Department of Orthopaedic Surgery, Hospital for Joint Diseases (A.R., S.V.), and Osteoporosis Center, Hospital for Joint Diseases (S.H.), NYU Langone Medical Center, New York, NY
| | - Alexandra Hotca
- From the Departments of Radiology (C.S.R., B.T.N., E.A.K., R.M.) and Orthopaedic Surgery (C.S.R.), University of Pennsylvania, 3400 Spruce St, 1 Founders Building, Philadelphia, PA 19104; and Department of Radiology, Center for Biomedical Imaging (A.H., G.C.), Department of Orthopaedic Surgery, Hospital for Joint Diseases (A.R., S.V.), and Osteoporosis Center, Hospital for Joint Diseases (S.H.), NYU Langone Medical Center, New York, NY
| | - Benjamin T Newman
- From the Departments of Radiology (C.S.R., B.T.N., E.A.K., R.M.) and Orthopaedic Surgery (C.S.R.), University of Pennsylvania, 3400 Spruce St, 1 Founders Building, Philadelphia, PA 19104; and Department of Radiology, Center for Biomedical Imaging (A.H., G.C.), Department of Orthopaedic Surgery, Hospital for Joint Diseases (A.R., S.V.), and Osteoporosis Center, Hospital for Joint Diseases (S.H.), NYU Langone Medical Center, New York, NY
| | - Austin Ramme
- From the Departments of Radiology (C.S.R., B.T.N., E.A.K., R.M.) and Orthopaedic Surgery (C.S.R.), University of Pennsylvania, 3400 Spruce St, 1 Founders Building, Philadelphia, PA 19104; and Department of Radiology, Center for Biomedical Imaging (A.H., G.C.), Department of Orthopaedic Surgery, Hospital for Joint Diseases (A.R., S.V.), and Osteoporosis Center, Hospital for Joint Diseases (S.H.), NYU Langone Medical Center, New York, NY
| | - Shaleen Vira
- From the Departments of Radiology (C.S.R., B.T.N., E.A.K., R.M.) and Orthopaedic Surgery (C.S.R.), University of Pennsylvania, 3400 Spruce St, 1 Founders Building, Philadelphia, PA 19104; and Department of Radiology, Center for Biomedical Imaging (A.H., G.C.), Department of Orthopaedic Surgery, Hospital for Joint Diseases (A.R., S.V.), and Osteoporosis Center, Hospital for Joint Diseases (S.H.), NYU Langone Medical Center, New York, NY
| | - Elizabeth A Kobe
- From the Departments of Radiology (C.S.R., B.T.N., E.A.K., R.M.) and Orthopaedic Surgery (C.S.R.), University of Pennsylvania, 3400 Spruce St, 1 Founders Building, Philadelphia, PA 19104; and Department of Radiology, Center for Biomedical Imaging (A.H., G.C.), Department of Orthopaedic Surgery, Hospital for Joint Diseases (A.R., S.V.), and Osteoporosis Center, Hospital for Joint Diseases (S.H.), NYU Langone Medical Center, New York, NY
| | - Rhiannon Miller
- From the Departments of Radiology (C.S.R., B.T.N., E.A.K., R.M.) and Orthopaedic Surgery (C.S.R.), University of Pennsylvania, 3400 Spruce St, 1 Founders Building, Philadelphia, PA 19104; and Department of Radiology, Center for Biomedical Imaging (A.H., G.C.), Department of Orthopaedic Surgery, Hospital for Joint Diseases (A.R., S.V.), and Osteoporosis Center, Hospital for Joint Diseases (S.H.), NYU Langone Medical Center, New York, NY
| | - Stephen Honig
- From the Departments of Radiology (C.S.R., B.T.N., E.A.K., R.M.) and Orthopaedic Surgery (C.S.R.), University of Pennsylvania, 3400 Spruce St, 1 Founders Building, Philadelphia, PA 19104; and Department of Radiology, Center for Biomedical Imaging (A.H., G.C.), Department of Orthopaedic Surgery, Hospital for Joint Diseases (A.R., S.V.), and Osteoporosis Center, Hospital for Joint Diseases (S.H.), NYU Langone Medical Center, New York, NY
| | - Gregory Chang
- From the Departments of Radiology (C.S.R., B.T.N., E.A.K., R.M.) and Orthopaedic Surgery (C.S.R.), University of Pennsylvania, 3400 Spruce St, 1 Founders Building, Philadelphia, PA 19104; and Department of Radiology, Center for Biomedical Imaging (A.H., G.C.), Department of Orthopaedic Surgery, Hospital for Joint Diseases (A.R., S.V.), and Osteoporosis Center, Hospital for Joint Diseases (S.H.), NYU Langone Medical Center, New York, NY
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Machine learning based analytics of micro-MRI trabecular bone microarchitecture and texture in type 1 Gaucher disease. J Biomech 2016; 49:1961-1968. [DOI: 10.1016/j.jbiomech.2016.04.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/29/2016] [Accepted: 04/07/2016] [Indexed: 11/21/2022]
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Chang G, Rajapakse CS, Regatte RR, Babb J, Saxena A, Belmont HM, Honig S. 3 Tesla MRI detects deterioration in proximal femur microarchitecture and strength in long-term glucocorticoid users compared with controls. J Magn Reson Imaging 2015; 42:1489-96. [PMID: 26073878 DOI: 10.1002/jmri.24927] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 04/07/2015] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Glucocorticoid-induced osteoporosis (GIO) is the most common secondary form of osteoporosis, and glucocorticoid users are at increased risk for fracture compared with nonusers. There is no established relationship between bone mineral density (BMD) and fracture risk in GIO. We used 3 Tesla (T) MRI to investigate how proximal femur microarchitecture is altered in subjects with GIO. METHODS This study had institutional review board approval. We recruited 6 subjects with long-term (> 1 year) glucocorticoid use (median age = 52.5 (39.2-58.7) years) and 6 controls (median age = 65.5 [62-75.5] years). For the nondominant hip, all subjects underwent dual-energy x-ray absorptiometry (DXA) to assess BMD and 3T magnetic resonance imaging (MRI, 3D FLASH) to assess metrics of bone microarchitecture and strength. RESULTS Compared with controls, glucocorticoid users demonstrated lower femoral neck trabecular number (-50.3%, 1.12 [0.84-1.54] mm(-1) versus 2.27 [1.88-2.73] mm(-1) , P = 0.02), plate-to-rod ratio (-20.1%, 1.48 [1.39-1.71] versus 1.86 [1.76-2.20], P = 0.03), and elastic modulus (-64.8% to -74.8%, 1.54 [1.22-3.19] GPa to 2.31 [1.87-4.44] GPa versus 6.15 [5.00-7.09] GPa to 6.59 [5.58-7.31] GPa, P < 0.05), and higher femoral neck trabecular separation (+192%, 0.705 [0.462-1.00] mm versus 0.241 [0.194-0.327] mm, P = 0.02). There were no differences in femoral neck trabecular thickness (-2.7%, 0.193 [0.184-0.217] mm versus 0.199 [0.179-0.210] mm, P = 0.94) or femoral neck BMD T-scores (+20.7%, -2.1 [-2.8 to -1.4] versus -2.6 [-3.3 to -2.5], P = 0.24) between groups. CONCLUSION The 3T MRI can potentially detect detrimental changes in proximal femur microarchitecture and strength in long-term glucocorticoid users.
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Affiliation(s)
- Gregory Chang
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Chamith S Rajapakse
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravinder R Regatte
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - James Babb
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Amit Saxena
- Divison of Rheumatology, Hospital for Joint Diseases, NYU Langone Medical Center, New York, New York, USA
| | - H Michael Belmont
- Divison of Rheumatology, Hospital for Joint Diseases, NYU Langone Medical Center, New York, New York, USA
| | - Stephen Honig
- Osteoporosis Center, Hospital for Joint Diseases, NYU Langone Medical Center, New York, New York, USA
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Sustained delivery of rhBMP-2 by means of poly(lactic-co-glycolic acid) microspheres: cranial bone regeneration without heterotopic ossification or craniosynostosis. Plast Reconstr Surg 2014; 134:51-59. [PMID: 24622573 DOI: 10.1097/prs.0000000000000287] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Commercially available recombinant human bone morphogenetic protein 2 (rhBMP2) has demonstrated efficacy in bone regeneration, but not without significant side effects. The authors used rhBMP2 encapsulated in poly(lactic-co-glycolic acid) (PLGA) microspheres placed in a rabbit cranial defect model to test whether low-dose, sustained delivery can effectively induce bone regeneration. METHODS The rhBMP2 was encapsulated in 15% PLGA using a double-emulsion, solvent extraction/evaporation technique, and its release kinetics and bioactivity were tested. Two critical-size defects (10 mm) were created in the calvaria of New Zealand white rabbits (5 to 7 months of age, male and female) and filled with a collagen scaffold containing either (1) no implant, (2) collagen scaffold only, (3) PLGA-rhBMP2 (0.1 μg per implant), or (4) free rhBMP2 (0.1 μg per implant). After 6 weeks, the rabbits were killed and defects were analyzed by micro-computed tomography, histology, and finite element analysis. RESULTS The rhBMP2 delivered by means of bioactive PLGA microspheres resulted in higher volumes and surface area coverage of new bone than an equal dose of free rhBMP2 by micro-computed tomography (p=0.025 and p=0.025). Finite element analysis indicated that the mechanical competence using the regional elastic modulus did not differ with rhBMP2 exposure (p=0.70). PLGA-rhBMP2 did not demonstrate heterotopic ossification, craniosynostosis, or seroma formation. CONCLUSIONS Sustained delivery by means of PLGA microspheres can significantly reduce the rhBMP2 dose required for de novo bone formation. Optimization of the delivery system may be a key to reducing the risk for recently reported rhBMP2-related adverse effects.
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Abstract
This review describes new technologies for the diagnosis and treatment, including fracture risk prediction, of postmenopausal osteoporosis. Four promising technologies and their potential for clinical translation and basic science studies are discussed. These include reference point indentation (RPI), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and magnetic resonance imaging (MRI). While each modality exploits different physical principles, the commonality is that none of them require use of ionizing radiation. To provide context for the new developments, brief summaries are provided for the current state of biomarker assays, fracture risk assessment (FRAX), and other fracture risk prediction algorithms and quantitative ultrasound (QUS) measurements.
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Affiliation(s)
- Bo Gong
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
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Hotca A, Ravichandra S, Mikheev A, Rusinek H, Chang G. Precision of volumetric assessment of proximal femur microarchitecture from high-resolution 3T MRI. Int J Comput Assist Radiol Surg 2014; 10:35-43. [PMID: 24799271 DOI: 10.1007/s11548-014-1009-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 04/15/2014] [Indexed: 12/17/2022]
Abstract
PURPOSE To evaluate the precision of measures of bone volume and bone volume fraction derived from high-resolution 3T MRI of proximal femur bone microarchitecture using non-uniformity correction. METHODS This HIPAA compliant, institutional review board approved study was conducted on six volunteers (mean age 56 ± 13 years), and written informed consent was obtained. All volunteers underwent a 3T FLASH MRI hip scan at three time points: baseline, second scan same day (intra-scans), and third scan one week later (inter-scans). Segmentation of femur images and values for total proximal femur volume (T), bone volume (B), and bone volume fraction (BVF) were calculated using in-house developed software, FireVoxel. Two types of non-uniformity corrections were applied to images (N3 and BiCal). Precision values were calculated using absolute percent error (APE). Statistical analysis was carried out using one-sample one-sided t test to observe the consistency of the precision and paired t test to compare between the various methods and scans. RESULTS No significant differences in bone volume measurements were observed for intra- and inter-scans. When using non-uniformity correction and assessing all subjects uniformly at the level of the lesser trochanter, precision values overall improved, especially significantly (p < 0.05) when measuring bone volume, B . B values using the combination of N3 or BiCal with CLT had a significant consistent APE values of less than 2.5 %, while BVF values were all consistently and significantly lower than 2.5 % APE. CONCLUSION Our results demonstrate the precision of high-resolution 3D MRI measures were comparable to that of dual-energy X-ray absorptiometry. Additional corrections to the analysis technique by cropping at the lesser trochanter or using non-uniformity corrections helped to improve precision. The high precision values from these MRI scans provide evidence for MRI of the proximal femur as a promising tool for osteoporosis diagnosis and treatment.
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Affiliation(s)
- Alexandra Hotca
- Department of Radiology, NYU Langone Medical Center, Center for Biomedical Imaging, New York University, 660 First Ave. 4th Floor, New York, NY, 10016, USA,
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Chang G, Honig S, Brown R, Deniz CM, Egol KA, Babb JS, Regatte RR, Rajapakse CS. Finite element analysis applied to 3-T MR imaging of proximal femur microarchitecture: lower bone strength in patients with fragility fractures compared with control subjects. Radiology 2014; 272:464-74. [PMID: 24689884 DOI: 10.1148/radiol.14131926] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE To determine the feasibility of using finite element analysis applied to 3-T magnetic resonance (MR) images of proximal femur microarchitecture for detection of lower bone strength in subjects with fragility fractures compared with control subjects without fractures. MATERIALS AND METHODS This prospective study was institutional review board approved and HIPAA compliant. Written informed consent was obtained. Postmenopausal women with (n = 22) and without (n = 22) fragility fractures were matched for age and body mass index. All subjects underwent standard dual-energy x-ray absorptiometry. Images of proximal femur microarchitecture were obtained by using a high-spatial-resolution three-dimensional fast low-angle shot sequence at 3 T. Finite element analysis was applied to compute elastic modulus as a measure of strength in the femoral head and neck, Ward triangle, greater trochanter, and intertrochanteric region. The Mann-Whitney test was used to compare bone mineral density T scores and elastic moduli between the groups. The relationship (R(2)) between elastic moduli and bone mineral density T scores was assessed. RESULTS Patients with fractures showed lower elastic modulus than did control subjects in all proximal femur regions (femoral head, 8.51-8.73 GPa vs 9.32-9.67 GPa; P = .04; femoral neck, 3.11-3.72 GPa vs 4.39-4.82 GPa; P = .04; Ward triangle, 1.85-2.21 GPa vs 3.98-4.13 GPa; P = .04; intertrochanteric region, 1.62-2.18 GPa vs 3.86-4.47 GPa; P = .006-.007; greater trochanter, 0.65-1.21 GPa vs 1.96-2.62 GPa; P = .01-.02), but no differences in bone mineral density T scores. There were weak relationships between elastic moduli and bone mineral density T scores in patients with fractures (R(2) = 0.25-0.31, P = .02-.04), but not in control subjects. CONCLUSION Finite element analysis applied to high-spatial-resolution 3-T MR images of proximal femur microarchitecture can allow detection of lower elastic modulus, a marker of bone strength, in subjects with fragility fractures compared with control subjects. MR assessment of proximal femur strength may provide information about bone quality that is not provided by dual-energy x-ray absorptiometry.
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Affiliation(s)
- Gregory Chang
- From the Department of Radiology, Center for Musculoskeletal Care (G.C.), Osteoporosis Center, Hospital for Joint Diseases (S.H.), Department of Orthopaedic Surgery, Hospital for Joint Diseases (K.A.E.), and Department of Radiology, Center for Biomedical Imaging (G.C., R.B., C.M.D., J.S.B., R.R.R.), NYU Langone Medical Center, 550 First Avenue, New York, NY 10016; and Department of Radiology, University of Pennsylvania School of Medicine, 3400 Spruce Street, Philadelphia, PA (C.S.R.)
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Al Mukaddam M, Rajapakse CS, Bhagat YA, Wehrli FW, Guo W, Peachey H, LeBeau SO, Zemel BS, Wang C, Swerdloff RS, Kapoor SC, Snyder PJ. Effects of testosterone and growth hormone on the structural and mechanical properties of bone by micro-MRI in the distal tibia of men with hypopituitarism. J Clin Endocrinol Metab 2014; 99:1236-44. [PMID: 24423356 PMCID: PMC3973782 DOI: 10.1210/jc.2013-3665] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Severe deficiencies of testosterone (T) and GH are associated with low bone mineral density (BMD) and increased fracture risk. Replacement of T in hypogonadal men improves several bone parameters. Replacement of GH in GH-deficient men improves BMD. OBJECTIVE Our objective was to determine whether T and GH treatment together improves the structural and mechanical parameters of bone more than T alone in men with hypopituitarism. DESIGN AND SUBJECTS This randomized, prospective, 2-year study included 32 men with severe deficiencies of T and GH due to panhypopituitarism. INTERVENTION Subjects were randomized to receive T alone (n = 15) or T and GH (n = 17) for 2 years. MAIN OUTCOME MEASURES We evaluated magnetic resonance microimaging-derived structural (bone volume fraction [BVF] and trabecular thickness) and mechanical (axial stiffness [AS], a measure of bone strength) properties of the distal tibia at baseline and after 1 and 2 years of treatment. RESULTS Treatment with T and GH did not affect BVF, thickness, or AS differently from T alone. T treatment in all subjects for 2 years increased trabecular BVF by 9.6% (P < .0001), trabecular thickness by 2.6% (P < .001), and trabecular AS by 9.8% (P < .001). In contrast, testosterone treatment in all subjects significantly increased cortical thickness by 2.4% (P < .01) but decreased cortical BVF by -4.7% (P < .01) and cortical AS by -6.9% (P < .01). CONCLUSION Combined T and GH treatment of men with hypopituitarism for 2 years did not improve the measured structural or mechanical parameters of the distal tibia more than T alone. However, testosterone significantly increased the structural and mechanical properties of trabecular bone but decreased most of these properties of cortical bone, illustrating the potential importance of assessing trabecular and cortical bone separately in future studies of the effect of testosterone on bone.
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Affiliation(s)
- Mona Al Mukaddam
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine (M.A.M., H.P., S.O.L., P.J.S.); Laboratory of Structural NMR Imaging, Department of Radiology (C.S.R., Y.A.B., F.W.W.), Department of Biostatistics and Epidemiology (W.G.), and the Clinical and Translational Research Center (S.C.K.), Raymond and Ruth Perelman School of Medicine, University of Pennsylvania; and the Division of Gastroenterology, Hepatology, and Nutrition (B.S.Z.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104; and Division of Endocrinology and Metabolism (C.W., R.S.S.), Harbor-University of California at Los Angeles Medical Center and Los Angeles Biomedical Research Institute, Torrance, California 90509
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Rajapakse CS, Phillips EA, Sun W, Wald MJ, Magland JF, Snyder PJ, Wehrli FW. Vertebral deformities and fractures are associated with MRI and pQCT measures obtained at the distal tibia and radius of postmenopausal women. Osteoporos Int 2014; 25:973-82. [PMID: 24221453 PMCID: PMC4746757 DOI: 10.1007/s00198-013-2569-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 10/24/2013] [Indexed: 11/26/2022]
Abstract
SUMMARY We investigated the association of postmenopausal vertebral deformities and fractures with bone parameters derived from distal extremities using MRI and pQCT. Distal extremity measures showed variable degrees of association with vertebral deformities and fractures, highlighting the systemic nature of postmenopausal bone loss. INTRODUCTION Prevalent vertebral deformities and fractures are known to predict incident further fractures. However, the association of distal extremity measures and vertebral deformities in postmenopausal women has not been fully established. METHODS This study involved 98 postmenopausal women (age range 60-88 years, mean 70 years) with DXA BMD T-scores at either the hip or spine in the range of -1.5 to -3.5. Wedge, biconcavity, and crush deformities were computed on the basis of spine MRI. Vertebral fractures were assessed using Eastell's criterion. Distal tibia and radius stiffness was computed using MRI-based finite element analysis. BMD at the distal extremities were obtained using pQCT. RESULTS Several distal extremity MRI and pQCT measures showed negative association with vertebral deformity on the basis of single parameter correlation (r up to 0.67) and two-parameter regression (r up to 0.76) models involving MRI stiffness and pQCT BMD. Subjects who had at least one prevalent vertebral fracture showed decreased MRI stiffness (up to 17.9 %) and pQCT density (up to 34.2 %) at the distal extremities compared to the non-fracture group. DXA lumbar spine BMD T-score was not associated with vertebral deformities. CONCLUSIONS The association between vertebral deformities and distal extremity measures supports the notion of postmenopausal osteoporosis as a systemic phenomenon.
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Affiliation(s)
- C S Rajapakse
- University of Pennsylvania School of Medicine, Philadelphia, PA, USA,
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Zhang N, Magland JF, Rajapakse CS, Bhagat YA, Wehrli FW. Potential of in vivo MRI-based nonlinear finite-element analysis for the assessment of trabecular bone post-yield properties. Med Phys 2013; 40:052303. [PMID: 23635290 DOI: 10.1118/1.4802085] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Bone strength is the key factor impacting fracture risk. Assessment of bone strength from high-resolution (HR) images have largely relied on linear micro-finite element analysis (μFEA) even though failure always occurs beyond the yield point, which is outside the linear regime. Nonlinear μFEA may therefore be more informative in predicting failure behavior. However, existing nonlinear models applied to trabecular bone (TB) have largely been confined to micro-computed tomography (μCT) and, more recently, HR peripheral quantitative computed tomography (HR-pQCT) images, and typically have ignored evaluation of the post-yield behavior. The primary purpose of this work was threefold: (1) to provide an improved algorithm and program to assess TB yield as well as post-yield properties; (2) to explore the potential benefits of nonlinear μFEA beyond its linear counterpart; and (3) to assess the feasibility and practicality of performing nonlinear analysis on desktop computers on the basis of micro-magnetic resonance (μMR) images obtained in vivo in patients. METHODS A method for nonlinear μFE modeling of TB yield as well as post-yield behavior has been designed where material nonlinearity is captured by adjusting the tissue modulus iteratively according to the tissue-level effective strain obtained from linear analysis using a computationally optimized algorithm. The software allows for images at in vivo μMRI resolution as input with retention of grayscale information. Associations between axial stiffness estimated from linear analysis and yield as well as post-yield parameters from nonlinear analysis were investigated from in vivo μMR images of the distal tibia (N = 20; ages: 58-84) and radius (N = 20; ages: 50-75). RESULTS All simulations were completed in 1 h or less for 61 strain levels using a desktop computer (dual quad-core Xeon 3.16 GHz CPUs equipped with 40 GB of RAM). Although yield stress and ultimate stress correlated strongly (R(2) > 0.95, p < 0.001) with axial stiffness, toughness correlated moderately at the distal tibia (R(2) = 0.81, p < 0.001) and only weakly at the distal radius (R(2) = 0.34, p = 0.007). Further, toughness was found to vary by up to 16% for bone of very similar axial stiffness (<2%). CONCLUSIONS The work demonstrates the practicality of nonlinear μFE simulations at in vivo μMRI resolution, as well as its potential for providing additional information beyond that obtainable from linear analysis. The data suggest that a direct assessment of toughness may provide information not captured by stiffness.
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Affiliation(s)
- Ning Zhang
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, Pennsylvania 19104, USA
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Stadelmann VA, Conway CM, Boyd SK. In vivomonitoring of bone–implant bond strength by microCT and finite element modelling. Comput Methods Biomech Biomed Engin 2013; 16:993-1001. [DOI: 10.1080/10255842.2011.648625] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Chang G, Rajapakse CS, Diamond M, Honig S, Recht MP, Weiss DS, Regatte RR. Micro-finite element analysis applied to high-resolution MRI reveals improved bone mechanical competence in the distal femur of female pre-professional dancers. Osteoporos Int 2013; 24:1407-17. [PMID: 22893356 PMCID: PMC3719856 DOI: 10.1007/s00198-012-2105-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 07/10/2012] [Indexed: 02/07/2023]
Abstract
UNLABELLED Micro-finite element analysis applied to high-resolution (0.234-mm length scale) MRI reveals greater whole and cancellous bone stiffness, but not greater cortical bone stiffness, in the distal femur of female dancers compared to controls. Greater whole bone stiffness appears to be mediated by cancellous, rather than cortical bone adaptation. INTRODUCTION The purpose of this study was to compare bone mechanical competence (stiffness) in the distal femur of female dancers compared to healthy, relatively inactive female controls. METHODS This study had institutional review board approval. We recruited nine female modern dancers (25.7±5.8 years, 1.63±0.06 m, 57.1±4.6 kg) and ten relatively inactive, healthy female controls matched for age, height, and weight (32.1±4.8 years, 1.6±0.04 m, 55.8±5.9 kg). We scanned the distal femur using a 7-T MRI scanner and a three-dimensional fast low-angle shot sequence (TR/TE=31 ms/5.1 ms, 0.234 mm×0.234 mm×1 mm, 80 slices). We applied micro-finite element analysis to 10-mm-thick volumes of interest at the distal femoral diaphysis, metaphysis, and epiphysis to compute stiffness and cross-sectional area of whole, cortical, and cancellous bone, as well as cortical thickness. We applied two-tailed t-tests and ANCOVA to compare groups. RESULTS Dancers demonstrated greater whole and cancellous bone stiffness and cross-sectional area at all locations (p<0.05). Cortical bone stiffness, cross-sectional area, and thickness did not differ between groups (>0.08). At all locations, the percent of intact whole bone stiffness for cortical bone alone was lower in dancers (p<0.05). Adjustment for cancellous bone cross-sectional area eliminated significant differences in whole bone stiffness between groups (p>0.07), but adjustment for cortical bone cross-sectional area did not (p<0.03). CONCLUSIONS Modern dancers have greater whole and cancellous bone stiffness in the distal femur compared to controls. Elevated whole bone stiffness in dancers may be mediated via cancellous, rather than cortical bone adaptation.
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Affiliation(s)
- G Chang
- Quantitative Multinuclear Musculoskeletal Imaging Group, Center for Biomedical Imaging, NYU Langone Medical Center, 660 First Avenue, 2nd Floor, New York, NY 10016, USA.
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Wehrli FW. Magnetic resonance of calcified tissues. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 229:35-48. [PMID: 23414678 PMCID: PMC4746726 DOI: 10.1016/j.jmr.2012.12.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 12/13/2012] [Accepted: 12/14/2012] [Indexed: 05/06/2023]
Abstract
MRI of the human body is largely made possible by the favorable relaxation properties of protons of water and triacyl glycerides prevalent in soft tissues. Hard tissues--key among them bone--are generally less amenable to measurement with in vivo MR imaging techniques, not so much as a result of the lower proton density but rather due to the extremely short life-times of the proton signal in water bound to solid-like entities, typically collagen, or being trapped in micro-pores. Either mechanism can enhance T2 relaxation by up to three orders of magnitude relative to their soft-tissue counterparts. Detection of these protons requires solid-state techniques that have emerged in recent years and that promise to add a new dimension to the study of hard tissues. Alternative approaches to probe calcified tissues exploit their characteristic magnetic properties. Bone, teeth and extra-osseous calcium-containing biomaterials are unique in that they are more diamagnetic than all other tissues and thus yield information indirectly by virtue of the induced magnetic fields present in their vicinity. Progress has also been made in methods allowing very high-resolution structural imaging of trabecular and cortical bone relying on detection of the surrounding soft-tissues. This brief review, much of it drawn from work conducted in the author's laboratory, seeks to highlight opportunities with focus on early-stage developments for image-based assessment of structure, function, physiology and mechanics of calcified tissues in humans via liquid and solid-state approaches, including proton, deuteron and phosphorus NMR and MRI.
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Affiliation(s)
- Felix W Wehrli
- Laboratory for Structural NMR Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, USA.
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Micro-architecture and mineralization of the human alveolar bone obtained with microCT. Arch Oral Biol 2012; 58:621-7. [PMID: 23123067 DOI: 10.1016/j.archoralbio.2012.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 07/04/2012] [Accepted: 10/01/2012] [Indexed: 11/23/2022]
Abstract
OBJECTIVES The primary dental implant stability depends on the location of the implant in the jaw. This study analysed the architecture and mineralization of the trabecular bone at different jaw locations and thereby identified potential prognostic factors for implant failure. It has checked the hypotheses: (1) the mandible contains more compact and less mineralized trabecular bone than the maxilla and (2) within the mandible the trabecular bone is more compact and less mineralized in the anterior region. METHODS Alveolar bone specimens were produced from the cadavers of ten humans (7 males and 3 females; mean age: 73.7±12.5 years) and scanned with a high-resolution microCT system. Volumes of interest were chosen next to the roots of molars and incisors in both the maxilla and mandible. Several morphological parameters as well as the tissue mineral density were determined. RESULTS The alveolar bone specimens had a very high bone volume fraction (mean=0.31) with large differences (SD=0.17) between and within subjects. Yet several significant differences were found between the maxilla and the mandible. The bone volume fraction and trabecular thickness were significantly higher in the mandible than in the maxilla (p<0.01). But the tissue mineral density was not significantly different. CONCLUSIONS A higher primary implant stability coincides with a higher bone volume fraction and degree of anisotropy Although local differences remain more important for implantology, the results suggest that the micro-structure also affects the implant stability. The tissue mineral density seems to have no predictive value.
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Jabłoński M, Gun'ko VM, Golovan AP, Leboda R, Skubiszewska-Zięba J, Pluta R, Turov VV. Textural characteristics of model and natural bone tissues and interfacial behavior of bound water. J Colloid Interface Sci 2012; 392:446-462. [PMID: 23142010 DOI: 10.1016/j.jcis.2012.08.070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 08/23/2012] [Accepted: 08/24/2012] [Indexed: 11/29/2022]
Abstract
Water, as a probe liquid bound in model systems (highly disperse hydroxyapatite - protein composites as a model of the main components of bones) and rat bone tissues healthy and affected by osteoporosis occurred due to experimental Alzheimer's disease (EAD), has been investigated using low-temperature (1)H NMR spectroscopy, NMR cryoporometry, TG/DTG/DTA, DSC, and TG and DSC thermoporometry. The textural characteristics of these intact systems cannot be studied using the standard adsorption methods, but the cryoporometry and thermoporometry methods give these characteristics. The (1)H NMR spectra of water bound in model and natural bone tissues include signals, which can be assigned to strongly associated (typical) water (SAW, chemical shift of proton resonance δ(H)=5-6 ppm) and weakly associated (atypical) water (WAW) at δ(H)=1-2 ppm. Contributions of SAW and WAW give information on textural organization of both model and natural bones. The influence of such co-adsorbates as HCl, CDCl(3), CD(3)CN, C(6)D(6), and (CD(3))(2)SO on the interfacial behavior and clustering of bound water depends on their polarity, amounts of components, and textural and structural features of the materials analyzed with the (1)H NMR spectroscopy and cryoporometry methods. According to the NMR cryoporometry data, the EAD causes an increase in nanoporosity of the bone tissues. The total porosity and the specific surface area of biostructures (accessible for water molecules and estimated using NMR cryoporometry and TG thermoporometry methods with a model of cylindrical pores) are larger for the EAD sample. Weakly polar chloroform-d has a significant influence on the organization of water in the bone tissue, and this effect is greater for the EAD sample as more porous material.
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Affiliation(s)
- Miroslaw Jabłoński
- Department of Orthopaedics and Rehabilitation, Lublin Medical University, 20-094 Lublin, Poland
| | - Vladimir M Gun'ko
- Chuiko Institute of Surface Chemistry, 17 General Naumov Street, 03164 Kiev, Ukraine.
| | - Alina P Golovan
- Chuiko Institute of Surface Chemistry, 17 General Naumov Street, 03164 Kiev, Ukraine
| | - Roman Leboda
- Faculty of Chemistry, Maria Curie-Sklodowska University, 20-031 Lublin, Poland
| | | | - Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Vladimir V Turov
- Chuiko Institute of Surface Chemistry, 17 General Naumov Street, 03164 Kiev, Ukraine
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Wald MJ, Magland JF, Rajapakse CS, Bhagat YA, Wehrli FW. Predicting trabecular bone elastic properties from measures of bone volume fraction and fabric on the basis of micromagnetic resonance images. Magn Reson Med 2012; 68:463-73. [PMID: 22162036 PMCID: PMC3374911 DOI: 10.1002/mrm.23253] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 08/28/2011] [Accepted: 09/22/2011] [Indexed: 11/10/2022]
Abstract
The relationship between fabric (a measure of structural anisotropy) and elastic properties of trabecular bone was examined by invoking morphology and homogenization theory on the basis of micromagnetic resonance images from the distal tibia in specimens (N = 30) and human subjects (N = 16) acquired at a 160 × 160 × 160 μm(3) voxel size. The fabric tensor was mapped in 7.5 × 7.5 × 7.5 mm(3) cubic subvolumes by a three-dimensional mean-intercept-length method. Elastic constants (three Young's and three shear moduli) were derived from linear microfinite element simulations of three-dimensional grayscale bone volume fraction-mapped images. In the specimen data, moduli fit power laws of bone volume fraction (bone volume/total volume) for all three test directions and subvolumes (R(2) = 0.92-0.98) with exponents ranging from 1.3 to 1.8. Weaker linear relationships were found for the in vivo data because of a narrower range in bone volume/total volume. When pooling the data for all test directions and subvolumes, bone volume/total volume predicted elastic moduli less well in the specimens (mean R(2) = 0.74) and not at all in vivo. A model of bone volume/total volume and fabric was highly predictive of microfinite element-derived Young's moduli: mean R(2) s of 0.98 and 0.82 (in vivo). The results show that fabric, an important predictor of bone mechanical properties, can be assessed in the limited resolution and signal-to-noise ratio regime of micromagnetic resonance images.
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Affiliation(s)
- Michael J Wald
- Department of Radiology, Laboratory for Structural NMR Imaging, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, United States of America
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Rajapakse CS, Leonard MB, Bhagat YA, Sun W, Magland JF, Wehrli FW. Micro-MR imaging-based computational biomechanics demonstrates reduction in cortical and trabecular bone strength after renal transplantation. Radiology 2012; 262:912-20. [PMID: 22357891 DOI: 10.1148/radiol.11111044] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To examine the ability of three-dimensional micro-magnetic resonance (MR) imaging-based computational biomechanics to detect mechanical alterations in trabecular bone and cortical bone in the distal tibia of incident renal transplant recipients 6 months after renal transplantation and compare them with bone mineral density (BMD) outcomes. MATERIALS AND METHODS The study was approved by the institutional review board and complied with HIPAA guidelines. Written informed consent was obtained from all subjects. Micro-MR imaging of distal tibial metaphysis was performed within 2 weeks after renal transplantation (baseline) and 6 months later in 49 participants (24 female; median age, 44 years; range, 19-61 years) with a clinical 1.5-T whole-body imager using a modified three-dimensional fast large-angle spin-echo pulse sequence. Micro-finite-element models for cortical bone, trabecular bone, and whole-bone section were generated from each image by delineating the endosteal and periosteal boundaries. Mechanical parameters (stiffness and failure load) were estimated with simulated uniaxial compression tests on the micro-finite-element models. Structural parameters (trabecular bone volume fraction [BV/TV, bone volume to total volume ratio], trabecular thickness [TbTh], and cortical thickness [CtTh]) were computed from micro-MR images. Total hip and spine areal BMD were determined with dual-energy x-ray absorptiometry (DXA). Parameters obtained at the follow-up were compared with the baseline values by using parametric or nonparametric tests depending on the normality of data. RESULTS All mechanical parameters were significantly lower at 6 months compared with baseline. Decreases in cortical bone, trabecular bone, and whole-bone stiffness were 3.7% (P = .03), 4.9% (P = .03), and 4.3% (P = .003), respectively. Decreases in cortical bone, trabecular bone, and whole-bone failure strength were 7.6% (P = .0003), 6.0% (P = .004), and 5.6% (P = .0004), respectively. Conventional structural measures, BV/TV, TbTh, and CtTh, did not change significantly. Spine BMD decreased by 2.9% (P < .0001), while hip BMD did not change significantly at DXA. CONCLUSION MR imaging-based micro-finite-element analysis suggests that stiffness and failure strength of the distal tibia decrease over a 6-month interval after renal transplantation.
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Affiliation(s)
- Chamith S Rajapakse
- Department of Radiology, University of Pennsylvania, 1 Founders, 3400 Spruce St, Philadelphia, PA 19104, USA.
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Magland JF, Zhang N, Rajapakse CS, Wehrli FW. Computationally-optimized bone mechanical modeling from high-resolution structural images. PLoS One 2012; 7:e35525. [PMID: 22558164 PMCID: PMC3338413 DOI: 10.1371/journal.pone.0035525] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 03/20/2012] [Indexed: 11/19/2022] Open
Abstract
Image-based mechanical modeling of the complex micro-structure of human bone has shown promise as a non-invasive method for characterizing bone strength and fracture risk in vivo. In particular, elastic moduli obtained from image-derived micro-finite element (μFE) simulations have been shown to correlate well with results obtained by mechanical testing of cadaveric bone. However, most existing large-scale finite-element simulation programs require significant computing resources, which hamper their use in common laboratory and clinical environments. In this work, we theoretically derive and computationally evaluate the resources needed to perform such simulations (in terms of computer memory and computation time), which are dependent on the number of finite elements in the image-derived bone model. A detailed description of our approach is provided, which is specifically optimized for μFE modeling of the complex three-dimensional architecture of trabecular bone. Our implementation includes domain decomposition for parallel computing, a novel stopping criterion, and a system for speeding up convergence by pre-iterating on coarser grids. The performance of the system is demonstrated on a dual quad-core Xeon 3.16 GHz CPUs equipped with 40 GB of RAM. Models of distal tibia derived from 3D in-vivo MR images in a patient comprising 200,000 elements required less than 30 seconds to converge (and 40 MB RAM). To illustrate the system's potential for large-scale μFE simulations, axial stiffness was estimated from high-resolution micro-CT images of a voxel array of 90 million elements comprising the human proximal femur in seven hours CPU time. In conclusion, the system described should enable image-based finite-element bone simulations in practical computation times on high-end desktop computers with applications to laboratory studies and clinical imaging.
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Affiliation(s)
- Jeremy F Magland
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, United States of America.
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Chang G, Rajapakse CS, Babb JS, Honig SP, Recht MP, Regatte RR. In vivo estimation of bone stiffness at the distal femur and proximal tibia using ultra-high-field 7-Tesla magnetic resonance imaging and micro-finite element analysis. J Bone Miner Metab 2012; 30:243-51. [PMID: 22124539 PMCID: PMC3723134 DOI: 10.1007/s00774-011-0333-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 10/26/2011] [Indexed: 01/13/2023]
Abstract
The goal of this study was to demonstrate the feasibility of using 7-Tesla (7T) magnetic resonance imaging (MRI) and micro-finite element analysis (µFEA) to evaluate mechanical and structural properties of whole, cortical, and trabecular bone at the distal femur and proximal tibia in vivo. 14 healthy subjects were recruited (age 40.7 ± 15.7 years). The right knee was scanned on a 7T MRI scanner using a 28 channel-receive knee coil and a three-dimensional fast low-angle shot sequence (TR/TE 20 ms/5.02 ms, 0.234 mm × 0.234 mm × 1 mm, 80 axial images, 7 min 9 s). Bone was analyzed at the distal femoral metaphysis, femoral condyles, and tibial plateau. Whole, cortical, and trabecular bone stiffness was computed using µFEA. Bone volume fraction (BVF), bone areas, and cortical thickness were measured. Trabecular bone stiffness (933.7 ± 433.3 MPa) was greater than cortical bone stiffness (216 ± 152 MPa) at all three locations (P < 0.05). Across locations, there were no differences in bone stiffness (whole, cortical, or trabecular). Whole, cortical, and trabecular bone stiffness correlated with BVF (R ≥ 0.69, P < 0.05) and inversely correlated with corresponding whole, cortical, and trabecular areas (R ≤ -0.54, P < 0.05), but not with cortical thickness (R < -0.11, P > 0.05). Whole, cortical, and trabecular stiffness correlated with body mass index (R ≥ 0.62, P < 0.05). In conclusion, at the distal femur and proximal tibia, trabecular bone contributes 66-74% of whole bone stiffness. 7T MRI and µFEA may be used as a method to provide insight into how structural properties of cortical or trabecular bone affect bone mechanical competence in vivo.
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Affiliation(s)
- Gregory Chang
- Quantitative Multinuclear Musculoskeletal Imaging Group, Center for Biomedical Imaging, Department of Radiology, NYU Langone Medical Center, 660 First Avenue, Room 231, New York, NY 10016, USA.
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Lam SCB, Wald MJ, Rajapakse CS, Liu Y, Saha PK, Wehrli FW. Performance of the MRI-based virtual bone biopsy in the distal radius: serial reproducibility and reliability of structural and mechanical parameters in women representative of osteoporosis study populations. Bone 2011; 49:895-903. [PMID: 21784189 PMCID: PMC3167016 DOI: 10.1016/j.bone.2011.07.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/14/2011] [Accepted: 07/08/2011] [Indexed: 11/25/2022]
Abstract
Serial reproducibility and reliability critically determine sensitivity to detect changes in response to intervention and provide a basis for sample size estimates. Here, we evaluated the performance of the MRI-based virtual bone biopsy in terms of 26 structural and mechanical parameters in the distal radius of 20 women in the age range of 50 to 75 years (mean=62.0 years, S.D.=8.1 years), representative of typical study populations in drug intervention trials and fracture studies. Subjects were examined three times at average intervals of 20.2 days (S.D.=14.5 days) by MRI at 1.5 T field strength at a voxel size of 137×137×410 μm(3). Methods involved prospective and retrospective 3D image registration and auto-focus motion correction. Analyses were performed from a central 5×5×5 mm(3) cuboid subvolume and trabecular volume consisting of a 13 mm axial slab encompassing the entire medullary cavity. Whole-volume axial stiffness and sub-regional Young's and shear moduli were computed by finite-element analysis. Whole-volume-derived aggregate mean coefficient of variation of all structural parameters was 4.4% (range 1.8% to 7.7%) and 4.0% for axial stiffness; corresponding data in the subvolume were 6.5% (range 1.6% to 13.0%) for structural, and 5.5% (range 4.6% to 6.5%) for mechanical parameters. Aggregate ICC was 0.976 (range 0.947 to 0.986) and 0.992 for whole-volume-derived structural parameters and axial stiffness, and 0.946 (range 0.752 to 0.991) and 0.974 (range 0.965 to 0.978) for subvolume-derived structural and mechanical parameters, respectively. The strongest predictors of whole-volume axial stiffness were BV/TV, junction density, skeleton density and Tb.N (R(2) 0.79-0.87). The same parameters were also highly predictive of sub-regional axial modulus (R(2) 0.88-0.91). The data suggest that the method is suited for longitudinal assessment of the response to therapy. The underlying technology is portable and should be compatible with all general-purpose MRI scanners, which is appealing considering the very large installed base of this modality.
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Affiliation(s)
- Shing Chun Benny Lam
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA.
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Bhagat YA, Rajapakse CS, Magland JF, Love JH, Wright AC, Wald MJ, Song HK, Wehrli FW. Performance of μMRI-Based virtual bone biopsy for structural and mechanical analysis at the distal tibia at 7T field strength. J Magn Reson Imaging 2011; 33:372-81. [PMID: 21274979 DOI: 10.1002/jmri.22439] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To assess the performance of a 3D fast spin echo (FSE) pulse sequence utilizing out-of-slab cancellation through phase alternation and micro-magnetic resonance imaging (μMRI)-based virtual bone biopsy processing methods to probe the serial reproducibility and sensitivity of structural and mechanical parameters of the distal tibia at 7.0T. MATERIALS AND METHODS The distal tibia of five healthy subjects was imaged at three timepoints with a 3D FSE sequence at 137 × 137 × 410 μm(3) voxel size. Follow-up images were retrospectively 3D registered to baseline images. Coefficients of variation (CV) and intraclass correlation coefficients (ICCs) for measures of scale and topology of the whole tibial trabecular bone (TB) cross-section as well as finite-element-derived Young's and shear moduli of central cuboidal TB subvolumes (8 × 8 × 5 mm(3) ) were evaluated as measures of reproducibility and reliability. Four additional cubic TB subregions (anterior, medial, lateral, and posterior) of similar dimensions were extracted and analyzed to determine associations between whole cross-section and subregional structural parameters. RESULTS The mean signal-to-noise ratio (SNR) over the 15 image acquisitions was 27.5 ± 2.1. Retrospective registration yielded an average common analysis volume of 67% across the three exams per subject. Reproducibility (mean CV = 3.6%; range, 1.5%-5%) and reliability (ICCs, 0.95-0.99) of all parameters permitted parameter-based discrimination of the five subjects in spite of the narrow age range (26-36 years) covered. Parameters characterizing topology were better able to distinguish two individuals who demonstrated similar values for scalar measurements (≈ 34% difference, P < 0.001). Whole-section axial stiffness encompassing the cortex was superior at distinguishing two individuals relative to its central subregional TB counterpart (≈ 8% difference; P < 0.05). Interregion comparisons showed that although all parameters were correlated (mean R(2) = 0.78; range 0.57-0.99), the strongest associations observed were those for the erosion index (mean R(2) = 0.95, P ≤ 0.01). CONCLUSION The reproducibility and structural and mechanical parameter-based discriminative ability achieved in five healthy subjects suggests that 7T-derived μMRI of TB can be applied towards serial patient studies of osteoporosis and may enable earlier detection of disease or treatment-based effects.
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Affiliation(s)
- Yusuf A Bhagat
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, MRI Education Center, Philadelphia, Pennsylvania 19104, USA
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Liu XS, Zhang XH, Rajapakse CS, Wald MJ, Magland J, Sekhon KK, Adam MF, Sajda P, Wehrli FW, Guo XE. Accuracy of high-resolution in vivo micro magnetic resonance imaging for measurements of microstructural and mechanical properties of human distal tibial bone. J Bone Miner Res 2010; 25:2039-50. [PMID: 20499379 PMCID: PMC3118020 DOI: 10.1002/jbmr.92] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Micro magnetic resonance imaging (µMRI) is an in vivo imaging method that permits 3D quantification of cortical and trabecular bone microstructure. µMR images can also be used for building microstructural finite element (µFE) models to assess bone stiffness, which highly correlates with bone's resistance to fractures. In order for µMRI-based microstructural and µFE analyses to become standard clinical tools for assessing bone quality, validation with a current gold standard, namely, high-resolution micro computed tomography (µCT), is required. Microstructural measurements of 25 human cadaveric distal tibias were performed for the registered µMR and µCT images, respectively. Next, whole bone stiffness, trabecular bone stiffness, and elastic moduli of cubic subvolumes of trabecular bone in both µMR and µCT images were determined by voxel-based µFE analysis. The bone volume fraction (BV/TV), trabecular number (Tb.N*), trabecular spacing (Tb.Sp*), cortical thickness (Ct.Th), and structure model index (SMI) based on µMRI showed strong correlations with µCT measurements (r(2) = 0.67 to 0.97), and bone surface-to-volume ratio (BS/BV), connectivity density (Conn.D), and degree of anisotropy (DA) had significant but moderate correlations (r(2) = 0.33 to 0.51). Each of these measurements also contributed to one or many of the µFE-predicted mechanical properties. However, model-independent trabecular thickness (Tb.Th*) based on µMRI had no correlation with the µCT measurement and did not contribute to any mechanical measurement. Furthermore, the whole bone and trabecular bone stiffness based on µMRI were highly correlated with those of µCT images (r(2) = 0.86 and 0.96), suggesting that µMRI-based µFE analyses can directly and accurately quantify whole bone mechanical competence. In contrast, the elastic moduli of the µMRI trabecular bone subvolume had significant but only moderate correlations with their gold standards (r(2) = 0.40 to 0.58). We conclude that most microstructural and mechanical properties of the distal tibia can be derived efficiently from µMR images and can provide additional information regarding bone quality.
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Affiliation(s)
- X Sherry Liu
- Division of Endocrinology, Department of Medicine, Columbia University, New York, NY 10027, USA
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