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Kim J, Kim JJ. Computationally efficient dominant load-based local bone microstructure reconstruction method using topology optimization. Comput Biol Med 2024; 180:108929. [PMID: 39068904 DOI: 10.1016/j.compbiomed.2024.108929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 07/03/2024] [Accepted: 07/18/2024] [Indexed: 07/30/2024]
Abstract
The bone microstructure of the human proximal femur is clinically crucial for diagnosing skeletal pathologies, such as osteoporosis and bone metastases. The topology optimization-based bone microstructure method obtains these bone microstructures by converting low-resolution (LR) images into high-resolution images. However, this method is inherently computationally inefficient as it requires numerous finite elements, iterative analyses, and parallel computations. Therefore, this study proposes a novel topology optimization-based localised bone microstructure reconstruction method using the dominant load, which highly affects the selected region of interest (ROI), for efficient resolution enhancement. The load dependency of selected ROIs is quantified with a load dependency score. Then, the localised finite element model is constructed based on the local load estimation. Finally, the selected dominant load is applied as an input for the topology optimization-based bone microstructure reconstruction method. The reconstructed bone microstructure was similar to that of the conventional method. The localised finite element model applied by the dominant load effectively and accurately reconstructed the bone morphology and exhibited high computational efficiency. In conclusion, the dominant load-based approach can be used to construct a reasonable trabecular bone structure for ROI with high computational efficiency. The predictive performance of the proposed method was validated and showed promise for accurate trabecular bone structure prediction without additional radiation exposure.
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Affiliation(s)
- Jisun Kim
- Department of Mechanical Engineering, 1095 Dalgubeol-daero, Dalseo-gu, Daegu, 42601, Keimyung University, Republic of Korea.
| | - Jung Jin Kim
- Department of Mechanical Engineering, 1095 Dalgubeol-daero, Dalseo-gu, Daegu, 42601, Keimyung University, Republic of Korea.
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2
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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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3
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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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4
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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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5
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Babazadeh Naseri A, Dunbar NJ, Baines AJ, Akin JE, Higgs Iii CF, Fregly BJ. Heterogeneous material mapping methods for patient-specific finite element models of pelvic trabecular bone: A convergence study. Med Eng Phys 2021; 96:1-12. [PMID: 34565547 DOI: 10.1016/j.medengphy.2021.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 07/18/2021] [Accepted: 07/20/2021] [Indexed: 12/17/2022]
Abstract
Patient-specific finite element (FE) models of bone require the assignment of heterogeneous material properties extracted from the subject's computed tomography (CT) images. Though node-based (NB) and element-based (EB) material mapping methods (MMMs) have been proposed, the sensitivity and convergence of FE models to MMM for varying mesh sizes are not well understood. In this work, CT-derived and synthetic bone material data were used to evaluate the effect of MMM on results from FE analyses. Pelvic trabecular bone data was extracted from CT images of six subjects, while synthetic data were created to resemble trabecular bone properties. The numerical convergence of FE bone models using different MMMs were evaluated for strain energy, von-Mises stress, and strain. NB and EB MMMs both demonstrated good convergence regarding total strain energy, with the EB method having a slight edge over the NB. However, at the local level (e.g., maximum stress and strain), FE results were sensitive to the field type, MMM, and the FE mesh size. The EB method exhibited superior performance in finer meshes relative to the voxel size. The NB method converged better than did the EB method for coarser meshes. These findings may lead to higher-fidelity patient-specific FE bone models.
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Affiliation(s)
| | - Nicholas J Dunbar
- Department of Mechanical Engineering, Rice University, Houston, TX 77005, USA
| | - Andrew J Baines
- Department of Mechanical Engineering, Rice University, Houston, TX 77005, USA
| | - John E Akin
- Department of Mechanical Engineering, Rice University, Houston, TX 77005, USA
| | - C Fred Higgs Iii
- Department of Mechanical Engineering, Rice University, Houston, TX 77005, USA
| | - Benjamin J Fregly
- Department of Mechanical Engineering, Rice University, Houston, TX 77005, USA.
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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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7
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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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8
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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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9
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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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10
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West SL, Rajapakse CS, Rayner T, Miller R, Slinger MA, Wells GD. The reproducibility of measuring trabecular bone parameters using a commercially available high-resolution magnetic resonance imaging approach: A pilot study. Bone Rep 2018; 8:180-186. [PMID: 29955637 PMCID: PMC6020268 DOI: 10.1016/j.bonr.2018.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 04/09/2018] [Accepted: 04/23/2018] [Indexed: 02/02/2023] Open
Abstract
Bone imaging is currently the best non-invasive way to assess changes to bone associated with aging or chronic disease. However, common imaging techniques such as dual energy x-ray absorptiometry are associated with limitations. Magnetic resonance imaging (MRI) is a radiation-free technique that can measure bone microarchitecture. However, published MRI bone assessment protocols use specialized MRI coils and sequences and therefore have limited transferability across institutions. We developed a protocol on a Siemens 3 Tesla MRI machine, using a commercially available coil (Siemens 15 CH knee coil), and manufacturer supplied sequences to acquire images at the tibia. We tested the reproducibility of the FSE and the GE Axial sequences and hypothesized that both would generate reproducible trabecular bone parameters. Eight healthy adults (age 25.5 ± 5.4 years) completed three measurements of each MRI sequence at the tibia. Each of the images was processed for 8 different bone parameters (such as volumetric bone volume fraction). We computed the coefficient of variation (CV) and intraclass correlation coefficients (ICC) to assess reproducibility and reliability. Both sequences resulted in trabecular parameters that were reproducible (CV <5% for most) and reliable (ICC >80% for all). Our study is one of the first to report that a commercially available MRI protocol can result in reproducible data, and is significant as MRI may be an accessible method to measure bone microarchitecture in clinical or research environments. This technique requires further testing, including validation and evaluation in other populations. Trabecular bone is difficult to measure using commercial MRI techniques Reproducibility of a MRI protocol measuring trabecular bone was assessed Tibia trabecular bone was reproducible using a knee coil and a FSE Axial sequence Tibia trabecular bone was reproducible using a knee coil and a GE Axial sequence
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Affiliation(s)
- Sarah L West
- Department of Biology, Trent/Fleming School of Nursing, Trent University, Peterborough, Ontario, Canada.,Translational Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Chamith S Rajapakse
- Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.,Department of Orthopaedic Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Tammy Rayner
- Radiology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Rhiannon Miller
- Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.,Department of Orthopaedic Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Michelle A Slinger
- Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.,Department of Orthopaedic Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Greg D Wells
- Translational Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
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11
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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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12
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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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13
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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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14
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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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15
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Kim JJ, Kim Y, Jang IG. Estimation of Local Bone Loads for the Volume of Interest. J Biomech Eng 2016; 138:2517987. [DOI: 10.1115/1.4033478] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Indexed: 11/08/2022]
Abstract
Computational bone remodeling simulations have recently received significant attention with the aid of state-of-the-art high-resolution imaging modalities. They have been performed using localized finite element (FE) models rather than full FE models due to the excessive computational costs of full FE models. However, these localized bone remodeling simulations remain to be investigated in more depth. In particular, applying simplified loading conditions (e.g., uniform and unidirectional loads) to localized FE models have a severe limitation in a reliable subject-specific assessment. In order to effectively determine the physiological local bone loads for the volume of interest (VOI), this paper proposes a novel method of estimating the local loads when the global musculoskeletal loads are given. The proposed method is verified for the three VOI in a proximal femur in terms of force equilibrium, displacement field, and strain energy density (SED) distribution. The effect of the global load deviation on the local load estimation is also investigated by perturbing a hip joint contact force (HCF) in the femoral head. Deviation in force magnitude exhibits the greatest absolute changes in a SED distribution due to its own greatest deviation, whereas angular deviation perpendicular to a HCF provides the greatest relative change. With further in vivo force measurements and high-resolution clinical imaging modalities, the proposed method will contribute to the development of reliable patient-specific localized FE models, which can provide enhanced computational efficiency for iterative computing processes such as bone remodeling simulations.
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Affiliation(s)
- Jung Jin Kim
- The Cho Chun Shik Graduate School for Green Transportation, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejon 305-701, South Korea e-mail:
| | - Youkyung Kim
- The Cho Chun Shik Graduate School for Green Transportation, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejon 305-701, South Korea e-mail:
| | - In Gwun Jang
- The Cho Chun Shik Graduate School for Green Transportation, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejon 305-701, South Korea e-mail:
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16
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Amjadi Kashani MR, Nikkhoo M, Khalaf K, Firoozbakhsh K, Arjmand N, Razmjoo A, Parnianpour M. An in silico parametric model of vertebrae trabecular bone based on density and microstructural parameters to assess risk of fracture in osteoporosis. Proc Inst Mech Eng H 2014; 228:1281-95. [DOI: 10.1177/0954411914563363] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Osteoporosis is a progressive bone disease characterized by deterioration in the quantity and quality of bone, leading to inferior mechanical properties and an increased risk of fracture. Current assessment of osteoporosis is typically based on bone densitometry tools such as Quantitative Computed Tomography (QCT) and Dual Energy X-ray absorptiometry (DEXA). These assessment modalities mainly rely on estimating the bone mineral density (BMD). Hence present densitometry tools describe only the deterioration of the quantity of bone associated with the disease and not the affected morphology or microstructural changes, resulting in potential incomplete assessment, many undetected patients, and unexplained fractures. In this study, an in-silico parametric model of vertebral trabecular bone incorporating both material and microstructural parameters was developed towards the accurate assessment of osteoporosis and the consequent risk of bone fracture. The model confirms that the mechanical properties such as strength and stiffness of vertebral trabecular tissue are highly influenced by material properties as well as morphology characteristics such as connectivity, which reflects the quality of connected inter-trabecular parts. The FE cellular solid model presented here provides a holistic approach that incorporates both material and microstructural elements associated with the degenerative process, and hence has the potential to provide clinical practitioners and researchers with more accurate assessment method for the degenerative changes leading to inferior mechanical properties and increased fracture risk associated with age and/or disease such as Osteoporosis.
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Affiliation(s)
| | - Mohammad Nikkhoo
- Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
- Institute of Biomedical Engineering, College of Medicine and Engineering, National Taiwan University, Taipei, Taiwan
| | - Kinda Khalaf
- Department of Biomedical Engineering, Khalifa University of Science, Technology and Research, Abu Dhabi, UAE
| | | | - Navid Arjmand
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - Arash Razmjoo
- Glenn Department of Civil Engineering, Clemson University, Clemson, SC, USA
| | - Mohamad Parnianpour
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
- Department of Industrial & Manufacturing Engineering, University of Wisconsin–Milwaukee, Milwaukee, WI, USA
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17
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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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18
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Zhang N, Magland JF, Song HK, Wehrli FW. Registration-based autofocusing technique for automatic correction of motion artifacts in time-series studies of high-resolution bone MRI. J Magn Reson Imaging 2014; 41:954-63. [PMID: 24803089 DOI: 10.1002/jmri.24646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 03/28/2014] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To develop a registration-based autofocusing (RAF) motion correction technique for high-resolution trabecular bone (TB) imaging and to evaluate its performance on in vivo MR data. MATERIALS AND METHODS The technique combines serial registration with a previously developed motion correction technique - autofocusing - for automatic correction of subject movement degradation of MR images acquired in longitudinal studies. The method was tested on in vivo images of the distal radius to measure improvements in serial reproducibility of parameters in 12 women (ages 50-75 years), and to compare with the navigator echo-based correction and autofocusing. Furthermore, the technique's ability to optimize the sensitivity to detect simulated bone loss was ascertained. RESULTS The new technique yielded superior reproducibility of image-derived structural and mechanical parameters. Average coefficient of variation across all parameters improved by 12.5%, 27.0%, 33.5%, and 37.0%, respectively, following correction by navigator echoes, autofocusing, and the RAF technique (without and with correction for rotational motion); average intra-class correlation coefficient increased by 1.2%, 2.2%, 2.8%, and 3.2%, respectively. Furthermore, simulated bone loss (5%) was well recovered independent of the choice of reference image (4.71% or 4.86% with respect to using either the original or the image subjected to bone loss) in the time series. CONCLUSION The data suggest that our technique simultaneously corrects for intra-scan motion corruption while improving inter-scan registration. Furthermore, the technique is not biased by small changes in bone architecture between time-points.
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Affiliation(s)
- Ning Zhang
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA
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19
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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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20
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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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Zhang N, Magland JF, Rajapakse CS, Lam SB, Wehrli FW. Assessment of trabecular bone yield and post-yield behavior from high-resolution MRI-based nonlinear finite element analysis at the distal radius of premenopausal and postmenopausal women susceptible to osteoporosis. Acad Radiol 2013; 20:1584-91. [PMID: 24200486 DOI: 10.1016/j.acra.2013.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 08/12/2013] [Accepted: 09/04/2013] [Indexed: 11/15/2022]
Abstract
RATIONALE AND OBJECTIVES To assess the performance of a nonlinear microfinite element model on predicting trabecular bone yield and post-yield behavior based on high-resolution in vivo magnetic resonance images via the serial reproducibility. MATERIALS AND METHODS The nonlinear model captures material nonlinearity by iteratively adjusting tissue-level modulus based on tissue-level effective strain. It enables simulations of trabecular bone yield and post-yield behavior from micro magnetic resonance images at in vivo resolution by solving a series of nonlinear systems via an iterative algorithm on a desktop computer. Measures of mechanical competence (yield strain/strength, ultimate strain/strength, modulus of resilience, and toughness) were estimated at the distal radius of premenopausal and postmenopausal women (N = 20, age range 50-75) in whom osteoporotic fractures typically occur. Each subject underwent three scans (20.2 ± 14.5 days). Serial reproducibility was evaluated via coefficient of variation (CV) and intraclass correlation coefficient (ICC). RESULTS Nonlinear simulations were completed in an average of 14 minutes per three-dimensional image data set involving analysis of 61 strain levels. The predicted yield strain/strength, ultimate strain/strength, modulus of resilience, and toughness had a mean value of 0.78%, 3.09 MPa, 1.35%, 3.48 MPa, 14.30 kPa, and 32.66 kPa, respectively, covering a substantial range by a factor of up to 4. Intraclass correlation coefficient ranged from 0.986 to 0.994 (average 0.991); CV ranged from 1.01% to 5.62% (average 3.6%), with yield strain and toughness having the lowest and highest CV values, respectively. CONCLUSIONS The data suggest that the yield and post-yield parameters have adequate reproducibility to evaluate treatment effects in interventional studies within short follow-up periods.
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Affiliation(s)
- Ning Zhang
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce St, Philadelphia, PA 19104
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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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Bijonowski BM, Miller WM, Wertheim JA. Bioreactor design for perfusion-based, highly-vascularized organ regeneration. Curr Opin Chem Eng 2013; 2:32-40. [PMID: 23542907 DOI: 10.1016/j.coche.2012.12.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Bioartificial or laboratory-grown organs is a growing field centered on developing replacement organs and tissues to restore body function and providing a potential solution to the shortage of donor organs for transplantation. With the entry of engineered planar tissues, such as bladder and trachea, into clinical studies, an increasing focus is being given to designing complex, three-dimensional solid organs. As tissues become larger, thicker and more complex, the vascular network becomes crucial for supplying nutrients and maintaining viability and growth of the neo-organ. Perfusion decellularization, the process of removing cells from an entire organ, leaves the matrix of the vascular network intact. Organ engineering requires a delicate process of decellularization, sterilization, reseeding with appropriate cells, and organ maturation and stimulation to ensure optimal development. The design of bioreactors to facilitate this sequence of events has been refined to the extent that some bioartificial organs grown in these systems have been transplanted into recipient animals with sustained, though limited, function. This review focuses on the state-of-art in bioreactor development for perfusion-based bioartificial organs and highlights specific design components in need of further refinement.
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Affiliation(s)
- Brent M Bijonowski
- Master of Biotechnology Program, McCormick School of Engineering, Northwestern University, Evanston, IL ; Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL
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