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Ahmed S, Rogers AV, Nowlan NC. Mechanical loading due to muscle movement regulates establishment of the collagen network in the developing murine skeleton. ROYAL SOCIETY OPEN SCIENCE 2023; 10:231023. [PMID: 37859832 PMCID: PMC10582611 DOI: 10.1098/rsos.231023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 09/14/2023] [Indexed: 10/21/2023]
Abstract
Mechanical loading is critical for collagen network maintenance and remodelling in adult skeletal tissues, but the role of loading in collagen network formation during development is poorly understood. We test the hypothesis that mechanical loading is necessary for the onset and maturation of spatial localization and structure of collagens in prenatal cartilage and bone, using in vivo and in vitro mouse models of altered loading. The majority of collagens studied was aberrant in structure or localization, or both, when skeletal muscle was absent in vivo. Using in vitro bioreactor culture system, we demonstrate that mechanical loading directly modulates the spatial localization and structure of collagens II and X. Furthermore, we show that mechanical loading in vitro rescues aspects of the development of collagens II and X from the effects of fetal immobility. In conclusion, our findings show that mechanical loading is a critical determinant of collagen network establishment during prenatal skeletal development.
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Affiliation(s)
- Saima Ahmed
- Department of Bioengineering, Imperial College London, London, UK
| | | | - Niamh C. Nowlan
- Department of Bioengineering, Imperial College London, London, UK
- School of Mechanical and Materials Engineering, University College Dublin, Dublin, Ireland
- UCD Conway Institute, University College Dublin, Dublin, Ireland
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Pang Y. Orientation dependent proton transverse relaxation in the human brain white matter: The magic angle effect on a cylindrical helix. Magn Reson Imaging 2023; 100:73-83. [PMID: 36965837 DOI: 10.1016/j.mri.2023.03.010] [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: 05/16/2022] [Revised: 03/15/2023] [Accepted: 03/21/2023] [Indexed: 03/27/2023]
Abstract
PURPOSE To overcome some limitations of previous proton orientation-dependent transverse relaxation formalisms in human brain white matter (WM) by a generalized magic angle effect function. METHODS A cylindrical helix model was developed embracing anisotropic rotational and translational diffusion of restricted molecules in WM, with the former characterized by an axially symmetric system. Transverse relaxation rates R2 and R2∗ were divided into isotropic R2i and anisotropic parts, R2a ∗ f(α,Φ - ε0), with α denoting an open angle and ε0 an orientation (Φ) offset from DTI-derived primary diffusivity direction. The proposed framework (Fit A) was compared to prior models without ε0 on previously published water and methylene proton transverse relaxation rates from developing, healthy, and pathological WM at 3 T. Goodness of fit was represented by root-mean-square error (RMSE). F-test and linear correlation were used with statistical significance set to P ≤ 0.05. RESULTS Fit A significantly (P < 0.01) outperformed prior models as demonstrated by reduced RMSEs, e.g., 0.349 vs. 0.724 in myelin water. Fitted ε0 was in good agreement with calculated ε0 from directional diffusivities. Compared with those from healthy adult, the fitted R2i, R2a, and α from neonates were substantially reduced but ε0 increased, consistent with developing myelination. Significant positive (R2i) and negative (α and R2a) correlations were found with aging (demyelination) in elderly. CONCLUSION The developed framework can better characterize orientation dependences from a wide range of proton transverse relaxation measurements in the human brain WM, thus shedding new light on myelin microstructural alterations at the molecular level.
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Affiliation(s)
- Yuxi Pang
- Department of Radiology, University of Michigan, 1500 E. Medical Center Dr., UH B2 RM A205F, Ann Arbor, MI 48109-5030, USA.
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Pang Y. Phase-shifted transverse relaxation orientation dependences in human brain white matter. NMR IN BIOMEDICINE 2023:e4925. [PMID: 36908074 DOI: 10.1002/nbm.4925] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/24/2023] [Accepted: 03/02/2023] [Indexed: 06/18/2023]
Abstract
This work aimed to demonstrate an essential phase shift ε 0 $$ {\varepsilon}_0 $$ for better quantifying R 2 $$ {R}_2 $$ and R 2 * $$ {R}_2^{\ast } $$ in human brain white matter (WM), and to further elucidate its origin related to the directional diffusivities from standard diffusion tensor imaging (DTI). ε 0 $$ {\varepsilon}_0 $$ was integrated into a proposed generalized transverse relaxation model for characterizing previously published R 2 $$ {R}_2 $$ and R 2 * $$ {R}_2^{\ast } $$ orientation dependence profiles in brain WM, and then comparisons were made with those without ε 0 $$ {\varepsilon}_0 $$ . It was theorized that anisotropic diffusivity direction ε $$ \varepsilon $$ was collinear with an axon fiber subject to all eigenvalues and eigenvectors from an apparent diffusion tensor. To corroborate the origin of ε 0 $$ {\varepsilon}_0 $$ , R 2 $$ {R}_2 $$ orientation dependences referenced by ε $$ \varepsilon $$ were compared with those referenced by the standard principal diffusivity direction Φ $$ \Phi $$ at b-values of 1000 and 2500 (s/mm2 ). These R 2 $$ {R}_2 $$ orientation dependences were obtained from T 2 $$ {T}_2 $$ -weighted images (b = 0) of ultrahigh-resolution Connectome DTI datasets in the public domain. A normalized root-mean-square error ( NRMSE % $$ NRMSE\% $$ ) and an F $$ F $$ -test were used for evaluating curve-fittings, and statistical significance was considered to be a p of 0.05 or less. A phase-shifted model resulted in significantly reduced NRMSE % $$ NRMSE\% $$ compared with that without ε 0 $$ {\varepsilon}_0 $$ in quantifying various R 2 $$ {R}_2 $$ and R 2 * $$ {R}_2^{\ast } $$ profiles, both in vivo and ex vivo at multiple B 0 $$ {B}_0 $$ fields. The R 2 $$ {R}_2 $$ profiles based on Φ $$ \Phi $$ manifested a right-shifted phase ( ε 0 > 0 $$ {\varepsilon}_0>0 $$ ) at two b-values, while those based on ε $$ \varepsilon $$ became free from ε 0 $$ {\varepsilon}_0 $$ . For all phase-shifted R 2 $$ {R}_2 $$ and R 2 * $$ {R}_2^{\ast } $$ profiles, ε 0 $$ {\varepsilon}_0 $$ generally depended on the directional diffusivities by tan - 1 D ⊥ / D ∥ $$ {\tan}^{-1}\left({D}_{\perp }/{D}_{\parallel}\right) $$ , as predicted. In summary, a ubiquitous phase shift ε 0 $$ {\varepsilon}_0 $$ has been demonstrated as a prerequisite for better quantifying transverse relaxation orientation dependences in human brain WM. Furthermore, the origin of ε 0 $$ {\varepsilon}_0 $$ associated with the directional diffusivities from DTI has been elucidated. These findings could have a significant impact on interpretations of prior R 2 $$ {R}_2 $$ and R 2 * $$ {R}_2^{\ast } $$ datasets and on future research.
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Affiliation(s)
- Yuxi Pang
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
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A numerical model for fibril remodeling in articular cartilage. Knee 2023; 41:83-96. [PMID: 36642036 DOI: 10.1016/j.knee.2022.12.009] [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: 07/12/2022] [Revised: 11/05/2022] [Accepted: 12/14/2022] [Indexed: 01/14/2023]
Abstract
BACKGROUND Collagen fibrils of articular cartilage have a distinct organization in mature human knee joints. It seems that a mechanobiological process drives the remodeling of newborn collagen fibrils with maturation. Therefore, the goal of the present study was to develop a collagen fibril remodeling algorithm that describes the unique collagen fibril organization in a 3D knee model. METHOD A fibril-reinforced, biphasic cartilage model was used with a cuboid and a 3D human knee joint geometries. An isotropic collagen fibril distribution was assigned to the cartilage at the start of the analysis. Each fibril was rotated towards the direction that resulted in a maximum stretch at each time increment of the loading cycle. RESULTS The resulting pattern for the collagen fibrils was compared with split line patterns of porcine knee joint cartilage and also data published in the literature. Fibrils on the articular surface had a radial pattern towards the geometrical centroid of the tibial and femoral cartilage. In the tibiofemoral contact regions of superficial zone, fibrils were oriented circumferentially and randomly. In the porcine samples, the split-line patterns were similar to those obtained theoretically. Depth-wise organization of fibril network was characterized by fibrils perpendicular to the subchondral bone in the deeper layers, and fibrils parallel to the surface of cartilage in the superficial zone. CONCLUSIONS The maximum stretch criterion, coupled with a biphasic constitutive model, successfully predicted the collagen fibril organization observed in the articular cartilage throughout the depth and on the articular surface.
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Integrating melt electrowriting and inkjet bioprinting for engineering structurally organized articular cartilage. Biomaterials 2022; 283:121405. [DOI: 10.1016/j.biomaterials.2022.121405] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 01/10/2022] [Accepted: 01/30/2022] [Indexed: 12/18/2022]
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Pang Y. Characterization of anisotropic T2W signals from human knee femoral cartilage: The magic angle effect on a spherical surface. NMR IN BIOMEDICINE 2021; 34:e4535. [PMID: 33963785 DOI: 10.1002/nbm.4535] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/23/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
The aim of the current study was to propose a generalized magic angle effect (gMAE) function for characterizing anisotropic T2W signals of human knee femoral cartilage with a spherical surface in clinical studies. A gMAE model function f(α, ε) was formulated for an orientation-dependent (ε) transverse T2 (i.e., 1/R2 ) relaxation in cartilage assuming an axially symmetric distribution (α) of collagen fibers. T2W sagittal images were acquired on an adult volunteer's healthy knee at 3 T, and ROI-based average signals S(ε) were extracted from angularly and radially segmented femoral cartilage. Compared with the standard MAE (sMAE) functions in the deep (DZ, α = 0°) and in the superficial (SZ, α = 90°) zones, a general form of R2 orientation-dependent function f(α, ε) was fitted to S(ε), including an isotropic R2 contribution (internal reference [REF]). Goodness of fit was evaluated by root-mean-square deviations (RMSDs). An F-test and a paired t-test were respectively used to assess significant differences between the observed variances and means, with statistical significance set to p less than .05. As a symmetric orientation-dependence function with a varying dynamic range, the proposed gMAE model outperformed the previous sMAE functions manifested by significantly reduced RMSDs in the DZ (0.239 ± 0.122 vs. 0.267 ± 0.097, p = .014) and in the SZ (0.183 ± 0.081 vs. 0.254 ± 0.085, p < .001). The fitted average angle α (38.5 ± 34.6° vs. 45.1 ± 30.1°, p < .43) and REF (5.092 ± 0.369 vs. 5.305 ± 0.440, p < .001) were smaller in the DZ than those in SZ, in good agreement with the reported collagen fibril microstructural configurations and the nonbound water contribution to R2 in articular cartilage. In conclusion, a general form of the magic angle effect function was proposed and demonstrated for better characterizing anisotropic T2W signals from human knee femoral cartilage at 3 T in clinical studies.
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Affiliation(s)
- Yuxi Pang
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
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Truhn D, Zwingenberger KT, Schock J, Abrar DB, Radke KL, Post M, Linka K, Knobe M, Kuhl C, Nebelung S. No pressure, no diamonds? - Static vs. dynamic compressive in-situ loading to evaluate human articular cartilage functionality by functional MRI. J Mech Behav Biomed Mater 2021; 120:104558. [PMID: 33957568 DOI: 10.1016/j.jmbbm.2021.104558] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 03/22/2021] [Accepted: 04/19/2021] [Indexed: 01/21/2023]
Abstract
Biomechanical Magnetic Resonance Imaging (MRI) of articular cartilage, i.e. its imaging under loading, is a promising diagnostic tool to assess the tissue's functionality in health and disease. This study aimed to assess the response to static and dynamic loading of histologically intact cartilage samples by functional MRI and pressure-controlled in-situ loading. To this end, 47 cartilage samples were obtained from the medial femoral condyles of total knee arthroplasties (from 24 patients), prepared to standard thickness, and placed in a standard knee joint in a pressure-controlled whole knee-joint compressive loading device. Cartilage samples' responses to static (i.e. constant), dynamic (i.e. alternating), and no loading, i.e. free-swelling conditions, were assessed before (δ0), and after 30 min (δ1) and 60 min (δ2) of loading using serial T1ρ maps acquired on a 3.0T clinical MRI scanner (Achieva, Philips). Alongside texture features, relative changes in T1ρ (Δ1, Δ2) were determined for the upper and lower sample halves and the entire sample, analyzed using appropriate statistical tests, and referenced to histological (Mankin scoring) and biomechanical reference measures (tangent stiffness). Histological, biomechanical, and T1ρ sample characteristics at δ0 were relatively homogenous in all samples. In response to loading, relative increases in T1ρ were strong and significant after dynamic loading (Δ1 = 10.3 ± 17.0%, Δ2 = 21.6 ± 21.8%, p = 0.002), while relative increases in T1ρ after static loading and in controls were moderate and not significant. Generally, texture features did not demonstrate clear loading-related associations underlying the spatial relationships of T1ρ. When realizing the clinical translation, this in-situ study suggests that serial T1ρ mapping is best combined with dynamic loading to assess cartilage functionality in humans based on advanced MRI techniques.
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Affiliation(s)
- Daniel Truhn
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology, D-52074, Aachen, Germany
| | - Ken Tonio Zwingenberger
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology, D-52074, Aachen, Germany
| | - Justus Schock
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany; Institute of Imaging and Computer Vision, RWTH Aachen University, D-52074, Aachen, Germany
| | - Daniel Benjamin Abrar
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany
| | - Karl Ludger Radke
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany
| | - Manuel Post
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology, D-52074, Aachen, Germany
| | - Kevin Linka
- Hamburg University of Technology, Department of Continuum and Materials Mechanics, D-21073, Hamburg, Germany
| | - Matthias Knobe
- Cantonal Hospital Lucerne, Department of Orthopaedic and Trauma Surgery, CH-6000, Lucerne, Switzerland
| | - Christiane Kuhl
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology, D-52074, Aachen, Germany
| | - Sven Nebelung
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany.
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Hafner T, Post M, Said O, Schad P, Schock J, Abrar DB, Knobe M, Kuhl C, Truhn D, Nebelung S. Identifying the imaging correlates of cartilage functionality based on quantitative MRI mapping - The collagenase exposure model. Acta Biomater 2020; 117:310-321. [PMID: 32980541 DOI: 10.1016/j.actbio.2020.09.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 01/05/2023]
Abstract
Cartilage functionality is determined by tissue structure and composition. If altered, cartilage is predisposed to premature degeneration. This pathomimetical study of early osteoarthritis evaluated the dose-dependant effects of collagenase-induced collagen disintegration and proteoglycan depletion on cartilage functionality as assessed by serial T1, T1ρ, T2, and T2* mapping under loading. 30 human femoral osteochondral samples underwent imaging on a clinical 3.0 T MRI scanner (Achieva, Philips) in the unloaded reference configuration (δ0) and under pressure-controlled quasi-static indentation loading to 15.1 N (δ1) and to 28.6 N (δ2). Imaging was performed before and after exposure to low (LC, 0.5 mg/mL; n = 10) or high concentration (HC, 1.5 mg/mL; n = 10) of collagenase. Untreated samples served as controls (n = 10). Loading responses were determined for the entire sample and the directly loaded (i.e. sub-pistonal) and bilaterally adjacent (i.e. peri‑pistonal) regions, referenced histologically, quantified as relative changes, and analysed using adequate parametric and non-parametric statistical tests. Dose-dependant surface disintegration and tissue loss were reflected by distinctly different pre- and post-exposure response-to-loading patterns. While T1 generally decreased with loading, regardless of collagenase exposure, T1ρ increased significantly after HC exposure (p = 0.008). Loading-induced decreases in T2 were significant after LC exposure (p = 0.006), while changes in T2* were ambiguous. In conclusion, aberrant loading-induced changes in T2 and T1ρ reflect moderate and severe matrix changes, respectively, and indicate the close interrelatedness of matrix changes and functionality in cartilage.
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Affiliation(s)
- Tobias Hafner
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology,D-52074 Aachen, Germany
| | - Manuel Post
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology,D-52074 Aachen, Germany
| | - Oliver Said
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology,D-52074 Aachen, Germany
| | - Philipp Schad
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology,D-52074 Aachen, Germany
| | - Justus Schock
- University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225 Dusseldorf, Germany; Institute of Computer Vision and Imaging, RWTH University Aachen, D-52074 Aachen, Germany
| | - Daniel Benjamin Abrar
- University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225 Dusseldorf, Germany
| | - Matthias Knobe
- Clinic for Orthopaedic and Trauma Surgery, Cantonal Hospital Luzern, CH-6004 Luzern, Switzerland
| | - Christiane Kuhl
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology,D-52074 Aachen, Germany
| | - Daniel Truhn
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology,D-52074 Aachen, Germany
| | - Sven Nebelung
- University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225 Dusseldorf, Germany.
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Dallora AL, Kvist O, Berglund JS, Ruiz SD, Boldt M, Flodmark CE, Anderberg P. Chronological Age Assessment in Young Individuals Using Bone Age Assessment Staging and Nonradiological Aspects: Machine Learning Multifactorial Approach. JMIR Med Inform 2020; 8:e18846. [PMID: 32955457 PMCID: PMC7536601 DOI: 10.2196/18846] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 08/06/2020] [Accepted: 08/13/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Bone age assessment (BAA) is used in numerous pediatric clinical settings as well as in legal settings when entities need an estimate of chronological age (CA) when valid documents are lacking. The latter case presents itself as critical as the law is harsher for adults and granted rights along with imputability changes drastically if the individual is a minor. Traditional BAA methods have drawbacks such as exposure of minors to radiation, they do not consider factors that might affect the bone age, and they mostly focus on a single region. Given the critical scenarios in which BAA can affect the lives of young individuals, it is important to focus on the drawbacks of the traditional methods and investigate the potential of estimating CA through BAA. OBJECTIVE This study aims to investigate CA estimation through BAA in young individuals aged 14-21 years with machine learning methods, addressing the drawbacks of research using magnetic resonance imaging (MRI), assessment of multiple regions of interest, and other factors that may affect the bone age. METHODS MRI examinations of the radius, distal tibia, proximal tibia, distal femur, and calcaneus were performed on 465 men and 473 women (aged 14-21 years). Measures of weight and height were taken from the subjects, and a questionnaire was given for additional information (self-assessed Tanner Scale, physical activity level, parents' origin, and type of residence during upbringing). Two pediatric radiologists independently assessed the MRI images to evaluate their stage of bone development (blinded to age, gender, and each other). All the gathered information was used in training machine learning models for CA estimation and minor versus adult classification (threshold of 18 years). Different machine learning methods were investigated. RESULTS The minor versus adult classification produced accuracies of 0.90 and 0.84 for male and female subjects, respectively, with high recalls for the classification of minors. The CA estimation for the 8 age groups (aged 14-21 years) achieved mean absolute errors of 0.95 years and 1.24 years for male and female subjects, respectively. However, for the latter, a lower error occurred only for the ages of 14 and 15 years. CONCLUSIONS This study investigates CA estimation through BAA using machine learning methods in 2 ways: minor versus adult classification and CA estimation in 8 age groups (aged 14-21 years), while addressing the drawbacks in the research on BAA. The first achieved good results; however, for the second case, the BAA was not precise enough for the classification.
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Affiliation(s)
- Ana Luiza Dallora
- Department of Health, Blekinge Institute of Technology, Karlskrona, Sweden
| | - Ola Kvist
- Department of Pediatric Radiology, Karolinska University Hospital, Stockholm, Sweden
| | | | - Sandra Diaz Ruiz
- Department of Pediatric Radiology, Karolinska University Hospital, Stockholm, Sweden
| | - Martin Boldt
- Department of Computer Science, Blekinge Institute of Technology, Karlskrona, Sweden
| | | | - Peter Anderberg
- Department of Health, Blekinge Institute of Technology, Karlskrona, Sweden
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Hafner T, Schock J, Post M, Abrar DB, Sewerin P, Linka K, Knobe M, Kuhl C, Truhn D, Nebelung S. A serial multiparametric quantitative magnetic resonance imaging study to assess proteoglycan depletion of human articular cartilage and its effects on functionality. Sci Rep 2020; 10:15106. [PMID: 32934341 PMCID: PMC7492285 DOI: 10.1038/s41598-020-72208-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/21/2020] [Indexed: 02/06/2023] Open
Abstract
Water, collagen, and proteoglycans determine articular cartilage functionality. If altered, susceptibility to premature degeneration is increased. This study investigated the effects of enzymatic proteoglycan depletion on cartilage functionality as assessed by advanced Magnetic Resonance Imaging (MRI) techniques under standardized loading. Lateral femoral condylar cartilage-bone samples from patients undergoing knee replacement (n = 29) were serially imaged by Proton Density-weighted and T1, T1ρ, T2, and T2* mapping sequences on a clinical 3.0 T MRI scanner (Achieva, Philips). Using pressure-controlled indentation loading, samples were imaged unloaded and quasi-statically loaded to 15.1 N and 28.6 N, and both before and after exposure to low-concentrated (LT, 0.1 mg/mL, n = 10) or high-concentrated trypsin (HT, 1.0 mg/mL, n = 10). Controls were not treated (n = 9). Responses to loading were assessed for the entire sample and regionally, i.e. sub- and peri-pistonally, and zonally, i.e. upper and lower sample halves. Trypsin effects were quantified as relative changes (Δ), analysed using appropriate statistical tests, and referenced histologically. Histological proteoglycan depletion was reflected by significant sub-pistonal decreases in T1 (p = 0.003) and T2 (p = 0.008) after HT exposure. Loading-induced changes in T1ρ and T2* were not related. In conclusion, proteoglycan depletion alters cartilage functionality and may be assessed using serial T1 and T2 mapping under loading.
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Affiliation(s)
- Tobias Hafner
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany
| | - Justus Schock
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Hospital Düsseldorf, Moorenstraße 5, 40225, Dusseldorf, Germany.,Institute of Computer Vision and Imaging, RWTH University Aachen, Aachen, Germany
| | - Manuel Post
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany
| | - Daniel Benjamin Abrar
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Hospital Düsseldorf, Moorenstraße 5, 40225, Dusseldorf, Germany
| | - Philipp Sewerin
- Medical Faculty, Department and Hiller-Research-Unit for Rheumatology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Kevin Linka
- Department of Continuum and Materials Mechanics, Hamburg University of Technology, Hamburg, Germany
| | - Matthias Knobe
- Clinic for Orthopaedic and Trauma Surgery, Cantonal Hospital Luzern, Luzern, Switzerland
| | - Christiane Kuhl
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany
| | - Daniel Truhn
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany
| | - Sven Nebelung
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Hospital Düsseldorf, Moorenstraße 5, 40225, Dusseldorf, Germany.
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Depth-dependent changes in cartilage T2 under compressive strain: a 7T MRI study on human knee cartilage. Osteoarthritis Cartilage 2020; 28:1276-1285. [PMID: 32474193 DOI: 10.1016/j.joca.2020.05.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 04/30/2020] [Accepted: 05/11/2020] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To assess the potential of using ΔT2 as an indirect index of cartilage strain by quantifying the relationship between local in situ compressive strain and ΔT2 through the full depth of human tibial and femoral articular cartilage. DESIGN Osteochondral samples (n = 4) of human tibial and femoral cartilage were harvested from cadavers and imaged in a Bruker 7T research MRI scanner under increasing displacement-controlled compressive strains. T2 was calculated for 3D double echo steady state (DESS) image volumes at each strain level. A decaying exponential model estimated local, depth-dependent strains. Strained image volumes were non-linearly warped back to their unloaded configurations and ΔT2 was calculated by image subtraction. Linear modeling assessed local relationships between strain and ΔT2. RESULTS Bulk average tibial T2 was 13.2 ms for unstrained cartilage and ranged from 13.0 to 13.1 ms under strain; femoral T2 was 14.0 ms for unstrained cartilage and ranged from 13.5 to 14.8 ms under strain. Local ΔT2 in strained cartilage varied with depth. Linear modeling revealed significant correlations between in situ strain and ΔT2 for both tibial and femoral cartilage; correlation coefficients were higher for tibial cartilage. CONCLUSIONS Changes in bulk average T2 are unsuitable as a quantitative surrogate measure of cartilage strain because bulk averaging masks important local variations. High-resolution measures of local ΔT2 have potential value as a surrogate for strain; however, their value is limited until we fully understand the influence of factors like age, joint surface and degeneration on the strain vs T2 relationship.
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Bourebaba L, Röcken M, Marycz K. Osteochondritis dissecans (OCD) in Horses - Molecular Background of its Pathogenesis and Perspectives for Progenitor Stem Cell Therapy. Stem Cell Rev Rep 2020; 15:374-390. [PMID: 30796679 PMCID: PMC6534522 DOI: 10.1007/s12015-019-09875-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Osteochondrosis (osteochondrosis dissecans; OCD) is a disease syndrome of growing cartilage related to different clinical entities such as epiphysitis, subchondral cysts and angular carpal deformities, which occurs in growing animals of all species, including horses. Nowadays, these disorders are affecting increasing numbers of young horses worldwide. As a complex multifactorial disease, OCD is initiated when failure in cartilage canals because of existing ischemia, chondrocyte biogenesis impairment as well as biochemical and genetic disruptions occur. Recently, particular attention have been accorded to the definition of possible relations between OCD and some metabolic disorders; in this way, implication of mitochondrial dysfunctions, endoplasmic reticulum disruptions, oxidative stress or endocrinological affections are among the most considered axes for future researches. As one of the most frequent cause of impaired orthopaedic potential, which may result in a sharp decrease in athletic performances of the affected animals, and lead to the occurrence of complications such as joint fragility and laminitis, OCD remains as one of the primary causes of considerable economic losses in all sections of the equine industry. It would therefore be important to provide more information on the exact pathophysiological mechanism(s) underlying early OC(D) lesions, in order to implement innovative strategies involving the use of progenitor stem cells, which are considered nowadays as a promising approach to regenerative medicine, with the potential to treat numerous orthopaedic disorders, including osteo-degenerative diseases, for prevention and reduction of incidence of the disease, not only in horses, but also in human medicine, as the equine model is already widely accepted by the scientific community and approved by the FDA, for the research and application of cellular therapies in the treatment of human conditions.
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Affiliation(s)
- Lynda Bourebaba
- Department of Experimental Biology, Faculty of Biology and Animal Science, Wrocław University of Environmental and Life Sciences, Norwida 27B, 50-375, Wrocław, Poland
| | - Michael Röcken
- Faculty of Veterinary Medicine, Equine Clinic - Equine Surgery, Justus-Liebig-University, 35392, Gießen, Germany
| | - Krzysztof Marycz
- Department of Experimental Biology, Faculty of Biology and Animal Science, Wrocław University of Environmental and Life Sciences, Norwida 27B, 50-375, Wrocław, Poland. .,Faculty of Veterinary Medicine, Equine Clinic - Equine Surgery, Justus-Liebig-University, 35392, Gießen, Germany.
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13
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Pang Y. An order parameter without magic angle effect (OPTIMA) derived from R 1 ρ dispersion in ordered tissue. Magn Reson Med 2019; 83:1783-1795. [PMID: 31691348 DOI: 10.1002/mrm.28045] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 12/25/2022]
Abstract
PURPOSE MR R2 imaging of ordered tissue exhibits the magic angle effect, potentially masking subtle pathological changes in cartilage. This work aimed to develop an orientation-independent order parameter (S) exclusively sensitive to collagen degeneration. METHODS A theory was developed based on R 1 ρ dispersion coupled with a simplified molecular motion model in which anisotropic R 2 a ( θ ) became directly proportional to correlation time τ b θ and S could be derived. This new parameter was validated with ex vivo R 1 ρ dispersion reported on orientated (n = 4), enzymatically depleted bovine cartilage (n = 6), and osteoarthritic human knee specimens (n = 14) at 9.4 Tesla, which was further demonstrated on 1 healthy human knee in vivo at 3 Tesla. RESULTS τ b θ from orientation-dependent R 1 ρ dispersion revealed a significantly high average correlation (r = 0.89 ± 0.05, P < 0.05) with R 2 a (θ) on cartilage samples and a moderate correlation (r = 0.48, P < 0.001) for the human knee in vivo. The derived S (10-3 ) significantly decreased in advanced osteoarthritis (1.64 ± 0.03 vs. 2.30 ± 0.11, P < 0.001) and collagen-depleted samples (1.30 ± 0.11 vs. 2.12 ± 0.12, P < 0.001) when compared with early osteoarthritis and the control, respectively. CONCLUSION The proposed order parameter could be a potentially useful orientation-independent MR biomarker for collagen alterations in cartilage and other highly structured tissues.
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Affiliation(s)
- Yuxi Pang
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
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14
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Nebelung S, Post M, Knobe M, Shah D, Schleich C, Hitpass L, Kuhl C, Thüring J, Truhn D. Human articular cartilage mechanosensitivity is related to histological degeneration - a functional MRI study. Osteoarthritis Cartilage 2019; 27:1711-1720. [PMID: 31319176 DOI: 10.1016/j.joca.2019.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/13/2019] [Accepted: 07/03/2019] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate changes in response to sequential pressure-controlled loading and unloading in human articular cartilage of variable histological degeneration using serial T1ρ mapping. METHOD We obtained 42 cartilage samples of variable degeneration from the medial femoral condyles of 42 patients undergoing total knee replacement. Samples were placed in a standardized artificial knee joint within an MRI-compatible whole knee-joint compressive loading device and imaged before (δ0), during (δld1, δld2, δld3, δld4, δld5) and after (δrl1, δrl2, δrl3, δrl4, δrl5) pressure-controlled loading to 0.663 ± 0.021 kN (94% body weight) using serial T1ρ mapping (spin-lock multigradient echo sequence; 3.0T MRI system [Achieva, Philips]). Reference assessment included histology (Mankin scoring) and conventional biomechanics (Tangent stiffness). We dichotomized sample into intact (n = 21) and degenerative (n = 21) based on histology and analyzed data using Mann Whitney, Kruskal Wallis, one-way ANOVA tests and Spearman's correlation, respectively. RESULTS At δ0, we found no significant differences between intact and degenerative samples, while the response-to-loading patterns were distinctly different. In intact samples, T1ρ increases were consistent and non-significant, while in degenerative samples, T1ρ increases were significantly higher (P = 0.004, δ0 vs δld1, δ0 vs δld3), yet undulating and variable. With unloading, T1ρ increases subsided, yet were persistently elevated beyond δ0. CONCLUSION Cartilage mechanosensitivity is related to histological degeneration and assessable by serial T1ρ mapping. Unloaded, T1ρ characteristics are not significantly different in intact vs degenerative cartilage, while load bearing is organized in intact cartilage and disorganized in degenerative cartilage.
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Affiliation(s)
- S Nebelung
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany.
| | - M Post
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany.
| | - M Knobe
- Department of Orthopaedic Trauma, Aachen University Hospital, Aachen, Germany.
| | - D Shah
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany.
| | - C Schleich
- Department of Diagnostic and Interventional Radiology, University of Düsseldorf, Düsseldorf, Germany.
| | - L Hitpass
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany.
| | - C Kuhl
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany.
| | - J Thüring
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany.
| | - D Truhn
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany; Institute of Imaging and Computer Vision, RWTH Aachen University, Aachen, Germany.
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15
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Weiger M, Pruessmann KP. Short-T 2 MRI: Principles and recent advances. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:237-270. [PMID: 31779882 DOI: 10.1016/j.pnmrs.2019.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/14/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Among current modalities of biomedical and diagnostic imaging, MRI stands out by virtue of its versatile contrast obtained without ionizing radiation. However, in various cases, e.g., water protons in tissues such as bone, tendon, and lung, MRI performance is limited by the rapid decay of resonance signals associated with short transverse relaxation times T2 or T2*. Efforts to address this shortcoming have led to a variety of specialized short-T2 techniques. Recent progress in this field expands the choice of methods and prompts fresh considerations with regard to instrumentation, data acquisition, and signal processing. In this review, the current status of short-T2 MRI is surveyed. In an attempt to structure the growing range of techniques, the presentation highlights overarching concepts and basic methodological options. The most frequently used approaches are described in detail, including acquisition strategies, image reconstruction, hardware requirements, means of introducing contrast, sources of artifacts, limitations, and applications.
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Affiliation(s)
- Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland.
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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16
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Differentiation of human cartilage degeneration by functional MRI mapping—an ex vivo study. Eur Radiol 2019; 29:6671-6681. [DOI: 10.1007/s00330-019-06283-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 04/25/2019] [Accepted: 05/22/2019] [Indexed: 12/26/2022]
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17
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Pang Y, Palmieri-Smith RM, Malyarenko DI, Swanson SD, Chenevert TL. A unique anisotropic R 2 of collagen degeneration (ARCADE) mapping as an efficient alternative to composite relaxation metric (R 2 -R 1 ρ ) in human knee cartilage study. Magn Reson Med 2019; 81:3763-3774. [PMID: 30793790 DOI: 10.1002/mrm.27621] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/11/2018] [Accepted: 11/09/2018] [Indexed: 12/19/2022]
Abstract
PURPOSE Anisotropic transverse R2 (1/T2 ) relaxation of water proton is sensitive to cartilage degenerative changes. The purpose is to develop an efficient method to extract this relaxation metric in clinical studies. METHODS Anisotropic R2 can be measured inefficiently by standard R2 mapping after removing an isotropic contribution obtained from R1 ρ mapping. In the proposed method, named as a unique anisotropic R2 of collagen degeneration (ARCADE) mapping, an assumed uniform isotropic R2 was estimated at magic angle locations in the deep cartilage, and an anisotropic R2 was thus isolated in a single T2W sagittal image. Five human knees from 4 volunteers were studied with standard R2 and R1 ρ mappings at 3T, and anisotropic R2 derived from ARCADE on the T2W (TE = 48.8 ms) image from R2 mapping was compared with the composite relaxation (R2 - R1 ρ ) using statistical analysis including Student's t-test and Pearson's correlation coefficient. RESULTS Anisotropic R2 (1/s) from ARCADE was highly positively correlated with but not significantly different from standard R2 - R1 ρ (1/s) in the segmented deep (r = 0.83 ± 0.06; 8.3 ± 2.9 vs. 7.3 ± 1.9, P = .50) and the superficial (r = 0.82 ± 0.05; 3.5 ± 2.4 vs. 4.5 ± 1.6, P = .39) zones. However, after eliminating systematic errors by the normalization in terms of zonal contrast, anisotropic R2 was significantly higher (60.2 ± 18.5% vs. 38.4 ± 16.6%, P < .01) than R2 - R1 ρ as predicted. CONCLUSION The proposed anisotropic R2 mapping could be an efficient alternative to the conventional approach, holding great promise in providing both high-resolution morphological and more sensitive transverse relaxation imaging from a single T2W scan in a clinical setting.
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Affiliation(s)
- Yuxi Pang
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - Riann M Palmieri-Smith
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan.,Department of Orthopedic Surgery, University of Michigan, Ann Arbor, Michigan
| | | | - Scott D Swanson
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
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18
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Nebelung S, Sondern B, Jahr H, Tingart M, Knobe M, Thüring J, Kuhl C, Truhn D. Non-invasive T1ρ mapping of the human cartilage response to loading and unloading. Osteoarthritis Cartilage 2018; 26:236-244. [PMID: 29175373 DOI: 10.1016/j.joca.2017.11.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 09/21/2017] [Accepted: 11/13/2017] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To define the physiological response to sequential loading and unloading in histologically intact human articular cartilage using serial T1ρ mapping, as T1ρ is considered to indicate the tissue's macromolecular content. METHOD 18 macroscopically intact cartilage-bone samples were obtained from the central lateral femoral condyles of 18 patients undergoing total knee replacement. Serial T1ρ mapping was performed on a clinical 3.0-T MRI system using a modified prostate coil. Spin-lock multiple gradient-echo sequences prior to, during and after standardized indentation loading (displacement controlled, strain 20%) were used to obtain seven serial T1ρ maps: unloaded (δ0), quasi-statically loaded (indentation1-indentation3) and under subsequent relaxation (relaxation1-relaxation3). After manual segmentation, zonal and regional regions-of-interest were defined. ROI-specific relative changes were calculated and statistically assessed using paired t-tests. Histological (Mankin classification) and biomechanical (unconfined compression) evaluations served as references. RESULTS All samples were histologically and biomechanically grossly intact (Mankin sum: 1.8 ± 1.2; Young's Modulus: 0.7 ± 0.4 MPa). Upon loading, T1ρ consistently increased throughout the entire sample thickness, primarily subpistonally (indentation1 [M ± SD]: 9.5 ± 7.8% [sub-pistonal area, SPA] vs 4.2 ± 5.8% [peri-pistonal area, PPA]; P < 0.001). T1ρ further increased with ongoing loading (indentation3: 14.1 ± 8.1 [SPA] vs 7.7 ± 5.9% [PPA]; P < 0.001). Even upon unloading (i.e., relaxation), T1ρ persistently increased in time. CONCLUSION Serial T1ρ-mapping reveals distinct and complex zonal and regional changes in articular cartilage as a function of loading and unloading. Thereby, longitudinal adaptive processes in hyaline cartilage become evident, which may be used for the tissue's non-invasive functional characterization by T1ρ.
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Affiliation(s)
- S Nebelung
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany.
| | - B Sondern
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany.
| | - H Jahr
- Department of Orthopaedics, Aachen University Hospital, Aachen, Germany.
| | - M Tingart
- Department of Orthopaedics, Aachen University Hospital, Aachen, Germany.
| | - M Knobe
- Department of Orthopaedic Trauma, Aachen University Hospital, Aachen, Germany.
| | - J Thüring
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany.
| | - C Kuhl
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany.
| | - D Truhn
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany.
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19
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Dymerska B, Bohndorf K, Schennach P, Rauscher A, Trattnig S, Robinson SD. In vivo phase imaging of human epiphyseal cartilage at 7 T. Magn Reson Med 2017; 79:2149-2155. [PMID: 28758241 DOI: 10.1002/mrm.26858] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 07/10/2017] [Accepted: 07/11/2017] [Indexed: 12/23/2022]
Abstract
PURPOSE To assess the potential clinical utility of in vivo susceptibility-weighted imaging and quantitative susceptibility mapping of growth cartilage in the juvenile human knee at 7 T. METHODS High-resolution gradient-echo images of the knees of six healthy children and adolescents aged 6 to 15 were acquired with a 28-channel coil at 7 T. Phase images from the coils were combined using a short echo-time reference scan method (COMPOSER). RESULTS Veins oriented perpendicular to the static B0 field appeared doubled in susceptibility-weighted imaging, but not quantitative susceptibility mapping. Veins and layers in the cartilage were visible in all children up to the age of 13. CONCLUSIONS Phase imaging using susceptibility-weighted imaging and quantitative susceptibility mapping allows the in vivo visualization of veins and layers in human growth cartilage. Magn Reson Med 79:2149-2155, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Barbara Dymerska
- High Field Magnetic Resonance Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria
| | - Klaus Bohndorf
- High Field Magnetic Resonance Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria
| | - Paul Schennach
- High Field Magnetic Resonance Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria
| | - Alexander Rauscher
- UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Siegfried Trattnig
- High Field Magnetic Resonance Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria
| | - Simon D Robinson
- High Field Magnetic Resonance Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria
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20
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Linka K, Itskov M, Truhn D, Nebelung S, Thüring J. T2 MR imaging vs. computational modeling of human articular cartilage tissue functionality. J Mech Behav Biomed Mater 2017; 74:477-487. [PMID: 28760354 DOI: 10.1016/j.jmbbm.2017.07.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/10/2017] [Accepted: 07/18/2017] [Indexed: 12/31/2022]
Abstract
The detection of early stages of cartilage degeneration remains diagnostically challenging. One promising non-invasive approach is to functionally assess the tissue response to loading by serial magnetic resonance (MR) imaging in terms of T2 mapping under simultaneous mechanical loading. As yet, however, it is not clear which cartilage component contributes to the tissue functionality as assessed by quantitative T2 mapping. To this end, quantitative T2 maps of histologically intact cartilage samples (n=8) were generated using a clinical 3.0-T MR imaging system. Using displacement-controlled quasi-static indentation loading, serial T2 mapping was performed at three defined strain levels and loading-induced relative changes were determined in distinct regions-of-interest. Samples underwent conventional biomechanical testing (by unconfined compression) as well as histological assessment (by Mankin scoring) for reference purposes. Moreover, an anisotropic hyperelastic constitutive model of cartilage was implemented into a finite element (FE) code for cross-referencing. In efforts to simulate the evolution of compositional and structural intra-tissue changes under quasi-static loading, the indentation-induced changes in quantitative T2 maps were referenced to underlying changes in cartilage composition and structure. These changes were parameterized as cartilage fluid, proteoglycan and collagen content as well as collagen orientation. On a pixel-wise basis, each individual component correlation with T2 relaxation times was determined by Spearman's ρs and significant correlations were found between T2 relaxation times and all four tissue parameters for all indentation strain levels. Thus, the biological changes in functional MR Imaging parameters such as T2 can further be characterized to strengthen the scientific basis of functional MRI techniques with regards to their perspective clinical applications.
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Affiliation(s)
- Kevin Linka
- Department of Continuum Mechanics, RWTH Aachen University, Kackertstr. 9, 52072 Aachen, Germany.
| | - Mikhail Itskov
- Department of Continuum Mechanics, RWTH Aachen University, Kackertstr. 9, 52072 Aachen, Germany
| | - Daniel Truhn
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Pauwelsstr. 30, 52074 Aachen, Germany
| | - Sven Nebelung
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Pauwelsstr. 30, 52074 Aachen, Germany
| | - Johannes Thüring
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Pauwelsstr. 30, 52074 Aachen, Germany
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21
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Nebelung S, Post M, Raith S, Fischer H, Knobe M, Braun B, Prescher A, Tingart M, Thüring J, Bruners P, Jahr H, Kuhl C, Truhn D. Functional in situ assessment of human articular cartilage using MRI: a whole-knee joint loading device. Biomech Model Mechanobiol 2017; 16:1971-1986. [PMID: 28685238 DOI: 10.1007/s10237-017-0932-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 06/23/2017] [Indexed: 12/22/2022]
Abstract
The response to loading of human articular cartilage as assessed by magnetic resonance imaging (MRI) remains to be defined in relation to histology and biomechanics. Therefore, an MRI-compatible whole-knee joint loading device for the functional in situ assessment of cartilage was developed and validated in this study. A formalin-fixed human knee was scanned by computed tomography in its native configuration and digitally processed to create femoral and tibial bone models. The bone models were covered by artificial femoral and tibial articular cartilage layers in their native configuration using cartilage-mimicking polyvinyl siloxane. A standardized defect of 8 mm diameter was created within the artificial cartilage layer at the central medial femoral condyle, into which native cartilage samples of similar dimensions were placed. After describing its design and specifications, the comprehensive validation of the device was performed using a hydraulic force gauge and digital electronic pressure-sensitive sensors. Displacement-controlled quasi-static uniaxial loading to 2.5 mm [Formula: see text] and 5.0 mm [Formula: see text] of the mobile tibia versus the immobile femur resulted in forces of [Formula: see text] N [Formula: see text] and [Formula: see text] N [Formula: see text] (on the entire joint) and local pressures of [Formula: see text] MPa [Formula: see text] and [Formula: see text] MPa [Formula: see text] (at the site of the cartilage sample). Upon confirming the MRI compatibility of the set-up, the response to loading of macroscopically intact human articular cartilage samples ([Formula: see text]) was assessed on a clinical 3.0-T MR imaging system using clinical standard proton-density turbo-spin echo sequences and T2-weighted multi-spin echo sequences. Serial imaging was performed at the unloaded state [Formula: see text] and at consecutive loading positions (i.e. at [Formula: see text] and [Formula: see text]. Biomechanical unconfined compression testing (Young's modulus) and histological assessment (Mankin score) served as the standards of reference. All samples were histologically intact (Mankin score, [Formula: see text]) and biomechanically reasonably homogeneous (Young's modulus, [Formula: see text] MPa). They could be visualized in their entirety by MRI and significant decreases in sample height [[Formula: see text]: [Formula: see text] mm; [Formula: see text]: [Formula: see text] mm; [Formula: see text]: [Formula: see text] mm; [Formula: see text] (repeated-measures ANOVA)] as well as pronounced T2 signal decay indicative of tissue pressurization were found as a function of compressive loading. In conclusion, our compression device has been validated for the noninvasive response-to-loading assessment of human articular cartilage by MRI in a close-to-physiological experimental setting. Thus, in a basic research context cartilage may be functionally evaluated beyond mere static analysis and in reference to histology and biomechanics.
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Affiliation(s)
- Sven Nebelung
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Pauwelsstrasse 30, 52074, Aachen, Germany.
| | - Manuel Post
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Stefan Raith
- Department of Dental Materials and Biomaterials Research, Aachen University Hospital, Aachen, Germany
| | - Horst Fischer
- Department of Dental Materials and Biomaterials Research, Aachen University Hospital, Aachen, Germany
| | - Matthias Knobe
- Department of Orthopaedic Trauma, Aachen University Hospital, Aachen, Germany
| | - Benedikt Braun
- Department of Trauma, Hand and Reconstructive Surgery, Saarland University Hospital, Homburg, Germany
| | - Andreas Prescher
- Institute of Molecular and Cellular Anatomy, Aachen University Hospital, Aachen, Germany
| | - Markus Tingart
- Department of Orthopaedics, Aachen University Hospital, Aachen, Germany
| | - Johannes Thüring
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Philipp Bruners
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Holger Jahr
- Department of Orthopaedics, Aachen University Hospital, Aachen, Germany
| | - Christiane Kuhl
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Daniel Truhn
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Pauwelsstrasse 30, 52074, Aachen, Germany
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Yuen J, Hung J, Wiggermann V, Robinson SD, McCormack R, d'Entremont AG, Rauscher A. Multi-echo GRE imaging of knee cartilage. J Magn Reson Imaging 2016; 45:1502-1513. [PMID: 27564991 DOI: 10.1002/jmri.25438] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/08/2016] [Indexed: 12/24/2022] Open
Abstract
PURPOSE To visualize healthy and abnormal articular cartilage, we investigated the potential of using the 3D multi-echo gradient echo (GRE) signal's magnitude and frequency and maps of T2* relaxation. MATERIALS AND METHODS After optimizing imaging parameters in five healthy volunteers, 3D multi-echo GRE magnetic resonance (MR) images were acquired at 3T in four patients with chondral damage prior to their arthroscopic surgery. Average magnitude and frequency information was extracted from the GRE images, and T2* maps were generated. Cartilage abnormalities were confirmed after arthroscopy and were graded using the Outerbridge classification scheme. Regions of interest were identified on average magnitude GRE images and compared to arthroscopy. RESULTS All four patients presented with regions of Outerbridge Grade I and II cartilage damage on arthroscopy. One patient had Grade III changes. Grade I, II, and III changes were detectable on average magnitude and T2* maps, while Grade II and higher changes were also observable on MR frequency maps. For average magnitude images of healthy volunteers, the signal-to-noise ratio of the magnitude image averaged over three echoes was 4.26 ± 0.32, 12.26 ± 1.09, 14.31 ± 1.93, and 13.36 ± 1.13 in bone, femoral, tibial, and patellar cartilage, respectively. CONCLUSION This proof-of-principle study demonstrates the feasibility of using different imaging contrasts from the 3D multi-echo GRE scan to visualize abnormalities of the articular cartilage. © 2016 International Society for Magnetic Resonance in Medicine Level of Evidence: 1 J. MAGN. RESON. IMAGING 2017;45:1502-1513.
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Affiliation(s)
- Joanna Yuen
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada.,Department of Pediatrics, University of British Columbia, Vancouver, Canada.,Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - Jachin Hung
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - Vanessa Wiggermann
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada.,Department of Pediatrics, University of British Columbia, Vancouver, Canada.,Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - Simon D Robinson
- High Field Magnetic Resonance Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Robert McCormack
- Department of Orthopaedics, University of British Columbia, Vancouver, Canada
| | - Agnes G d'Entremont
- Department of Mechanical Engineering, University of British Columbia, Vancouver, Canada.,Centre for Hip Health and Mobility, University of British Columbia, Vancouver, Canada.,Child and Family Research Institute, University of British Columbia, Vancouver, Canada
| | - Alexander Rauscher
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada.,Department of Pediatrics, University of British Columbia, Vancouver, Canada.,Child and Family Research Institute, University of British Columbia, Vancouver, Canada
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Zhuang Z, Lee JH, Badar F, Xu J, Xia Y. The influences of different spatial resolutions on the characteristics of T2 relaxation times in articular cartilage: A coarse-graining study of the microscopic magnetic resonance imaging data. Microsc Res Tech 2016; 79:754-65. [PMID: 27297720 DOI: 10.1002/jemt.22694] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/23/2016] [Accepted: 05/25/2016] [Indexed: 11/09/2022]
Abstract
Microscopic magnetic resonance imaging (µMRI) T2 data from canine cartilage at different tibial locations were analyzed to investigate the influences of spatial resolution and pixel position on the T2 sensitivity to osteoarthritis (OA). Five experimental factors were investigated: inaccurate pixel position, different pixel resolutions, different specimen orientations in the magnetic field, topographical variations over the tibial surface, and different OA stages. A number of significant trends were identified in this analysis, which shows the subtle but substantial influences to our abilities of detecting OA due to T2 changes. In particular, any deviation in locating the cartilage pixels may result in erratic values near the cartilage surface. Significant differences were found in T2 values between nearly any two comparison-groups under all resolutions both in the meniscus-covered and -uncovered areas, which were also showed interaction between the OA degradation stages. This multiresolution project should help to improve the detection sensitivities of MRI toward cartilage degeneration. Microsc. Res. Tech. 79:754-765, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Zhiguo Zhuang
- Department of Radiology, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People's Republic of China.,Department of Physics and Center for Biomedical Research, Oakland University, Rochester, Michigan
| | - Ji Hyun Lee
- Department of Physics and Center for Biomedical Research, Oakland University, Rochester, Michigan
| | - Farid Badar
- Department of Physics and Center for Biomedical Research, Oakland University, Rochester, Michigan
| | - Jianrong Xu
- Department of Radiology, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Yang Xia
- Department of Physics and Center for Biomedical Research, Oakland University, Rochester, Michigan
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Sakai N, Hashimoto C, Yarimitsu S, Sawae Y, Komori M, Murakami T. A functional effect of the superficial mechanical properties of articular cartilage as a load bearing system in a sliding condition. BIOSURFACE AND BIOTRIBOLOGY 2016. [DOI: 10.1016/j.bsbt.2016.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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UTE bi-component analysis of T2* relaxation in articular cartilage. Osteoarthritis Cartilage 2016; 24:364-73. [PMID: 26382110 PMCID: PMC4898889 DOI: 10.1016/j.joca.2015.08.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 07/22/2015] [Accepted: 08/29/2015] [Indexed: 02/02/2023]
Abstract
OBJECTIVES To determine T2* relaxation in articular cartilage using ultrashort echo time (UTE) imaging and bi-component analysis, with an emphasis on the deep radial and calcified cartilage. METHODS Ten patellar samples were imaged using two-dimensional (2D) UTE and Car-Purcell-Meiboom-Gill (CPMG) sequences. UTE images were fitted with a bi-component model to calculate T2* and relative fractions. CPMG images were fitted with a single-component model to calculate T2. The high signal line above the subchondral bone was regarded as the deep radial and calcified cartilage. Depth and orientation dependence of T2*, fraction and T2 were analyzed with histopathology and polarized light microscopy (PLM), confirming normal regions of articular cartilage. An interleaved multi-echo UTE acquisition scheme was proposed for in vivo applications (n = 5). RESULTS The short T2* values remained relatively constant across the cartilage depth while the long T2* values and long T2* fractions tended to increase from subchondral bone to the superficial cartilage. Long T2*s and T2s showed significant magic angle effect for all layers of cartilage from the medial to lateral facets, while the short T2* values and T2* fractions are insensitive to the magic angle effect. The deep radial and calcified cartilage showed a mean short T2* of 0.80 ± 0.05 ms and short T2* fraction of 39.93 ± 3.05% in vitro, and a mean short T2* of 0.93 ± 0.58 ms and short T2* fraction of 35.03 ± 4.09% in vivo. CONCLUSION UTE bi-component analysis can characterize the short and long T2* values and fractions across the cartilage depth, including the deep radial and calcified cartilage. The short T2* values and T2* fractions are magic angle insensitive.
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Hinderer S, Brauchle E, Schenke-Layland K. Generation and Assessment of Functional Biomaterial Scaffolds for Applications in Cardiovascular Tissue Engineering and Regenerative Medicine. Adv Healthc Mater 2015; 4:2326-41. [PMID: 25778713 PMCID: PMC4745029 DOI: 10.1002/adhm.201400762] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 02/11/2015] [Indexed: 12/27/2022]
Abstract
Current clinically applicable tissue and organ replacement therapies are limited in the field of cardiovascular regenerative medicine. The available options do not regenerate damaged tissues and organs, and, in the majority of the cases, show insufficient restoration of tissue function. To date, anticoagulant drug-free heart valve replacements or growing valves for pediatric patients, hemocompatible and thrombus-free vascular substitutes that are smaller than 6 mm, and stem cell-recruiting delivery systems that induce myocardial regeneration are still only visions of researchers and medical professionals worldwide and far from being the standard of clinical treatment. The design of functional off-the-shelf biomaterials as well as automatable and up-scalable biomaterial processing methods are the focus of current research endeavors and of great interest for fields of tissue engineering and regenerative medicine. Here, various approaches that aim to overcome the current limitations are reviewed, focusing on biomaterials design and generation methods for myocardium, heart valves, and blood vessels. Furthermore, novel contact- and marker-free biomaterial and extracellular matrix assessment methods are highlighted.
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Affiliation(s)
- Svenja Hinderer
- Department of Cell and Tissue Engineering, Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB), Nobelstrasse 12, Stuttgart, 70569, Germany
- Department of Women's Health, Research Institute for Women's Health, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen, 72076, Germany
| | - Eva Brauchle
- Department of Cell and Tissue Engineering, Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB), Nobelstrasse 12, Stuttgart, 70569, Germany
- Department of Women's Health, Research Institute for Women's Health, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen, 72076, Germany
- Institute of Interfacial Process Engineering and Plasma Technology (IGVP), University of Stuttgart, Nobelstrasse 12, Stuttgart, 70569, Germany
| | - Katja Schenke-Layland
- Department of Cell and Tissue Engineering, Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB), Nobelstrasse 12, Stuttgart, 70569, Germany
- Department of Women's Health, Research Institute for Women's Health, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen, 72076, Germany
- Department of Medicine/Cardiology, Cardiovascular Research Laboratories, David Geffen School of Medicine at the, University of California Los Angeles (UCLA), Los Angeles, CA, USA
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Mabuma J, Schwarze M, Hurschler C, Markert B, Ehlers W. Effects of osteoarthritis and pathological walking on contact stresses in femoral cartilage. Biomech Model Mechanobiol 2015; 14:1167-80. [DOI: 10.1007/s10237-015-0663-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 02/26/2015] [Indexed: 11/30/2022]
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Brown DS, Durkan MG, Foss EW, Szumowski J, Crawford DC. Temporal in vivo assessment of fresh osteochondral allograft transplants to the distal aspect of the femur by dGEMRIC (delayed gadolinium-enhanced MRI of cartilage) and zonal T2 mapping MRI. J Bone Joint Surg Am 2014; 96:564-72. [PMID: 24695923 DOI: 10.2106/jbjs.k.01456] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Zonal T2 mapping and dGEMRIC (delayed gadolinium-enhanced magnetic resonance imaging of cartilage) are diagnostic quantitative techniques to evaluate the biochemical health of articular cartilage. We adapted these techniques to investigate the results of osteochondral allograft transplantation and correlated the findings with patient-reported outcomes. METHODS Nine patients with contained ICRS (International Cartilage Repair Society) grade-4 defects of the articular portion of a femoral condyle were treated with fresh osteochondral allografts and were evaluated prospectively with dGEMRIC and T2 mapping before and after gadolinium administration. The KOOS (Knee Injury Osteoarthritis Outcome Score) and IKDC (International Knee Documentation Committee) subjective scores were obtained at baseline and at one and two years postoperatively. For quantitative T2 mapping, regions of interest were drawn in the deep and superficial layers of allograft and control cartilage. For dGEMRIC analyses, the relaxation rate, post-gadolinium change in relaxation rate, and ratio between changes in the allograft and control regions of interest were calculated from T1 values. RESULTS The mean ratio between the post-gadolinium changes in the allograft and control cartilage was 1.13 at one year and 1.55 at two years, and the ratio increased in eight of nine patients from one to two years. There was no difference between the mean T2 values in the deep zone of the allograft and control cartilage at one or two years (p > 0.05), but mean T2 values were higher in the superficial zone of the allograft cartilage at one (p < 0.0001) and two (p < 0.028) years. The mean improvement from baseline was significant at one and two years for the IKDC and all five KOOS subdomains (p < 0.05). All or nearly all patients showed improvements in all clinical outcomes scores at one year. CONCLUSIONS Functional MRI techniques can be applied to noninvasively assess the biochemical health of cartilage after osteochondral allograft transplantation. The MRI findings correlated with certain patient-reported outcomes in the early postoperative period. Relative glycosaminoglycan content and the collagen structure of allograft cartilage may undergo time-dependent degeneration. A patient's perception of clinical outcome and quality of life is likely multifactorial and is impacted by more than the health of the allograft cartilage.
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Affiliation(s)
- Dawson S Brown
- Departments of Orthopaedics and Rehabilitation (D.S.B. and D.C.C.) and Radiology (E.W.F. and J.S.), Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Mail Code OP31, Portland, OR 97239. E-mail address for D.C. Crawford:
| | | | - Erik W Foss
- Departments of Orthopaedics and Rehabilitation (D.S.B. and D.C.C.) and Radiology (E.W.F. and J.S.), Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Mail Code OP31, Portland, OR 97239. E-mail address for D.C. Crawford:
| | - Jerzy Szumowski
- Departments of Orthopaedics and Rehabilitation (D.S.B. and D.C.C.) and Radiology (E.W.F. and J.S.), Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Mail Code OP31, Portland, OR 97239. E-mail address for D.C. Crawford:
| | - Dennis C Crawford
- Departments of Orthopaedics and Rehabilitation (D.S.B. and D.C.C.) and Radiology (E.W.F. and J.S.), Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Mail Code OP31, Portland, OR 97239. E-mail address for D.C. Crawford:
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Garnov N, Gründer W, Thörmer G, Trampel R, Turner R, Kahn T, Busse H. In vivo MRI analysis of depth-dependent ultrastructure in human knee cartilage at 7 T. NMR IN BIOMEDICINE 2013; 26:1412-1419. [PMID: 23801556 DOI: 10.1002/nbm.2968] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 02/26/2013] [Accepted: 04/01/2013] [Indexed: 06/02/2023]
Abstract
Signal intensities of T2-weighted magnetic resonance images depend on the local fiber arrangement in hyaline cartilage. The aims of this study were to determine whether angle-sensitive MRI at 7 T can be used to quantify the cartilage ultrastructure of the knee in vivo and to assess potential differences with age. Ten younger (21-30) and ten older (55-76 years old) healthy volunteers were imaged with a T2-weighted spin-echo sequence in a 7 T whole-body MRI. A "fascicle" model was assumed to describe the depth-dependent fiber arrangement of cartilage. The R/T boundary positions between radial and transitional zones were assessed from intensity profiles in small regions of interest in the femur and tibia, and normalized to cartilage thickness using logistic curve fits. The quality of our highly resolved (0.3 × 0.3 × 1.0 mm(3)) MR cartilage images were high enough for quantitative analysis (goodness of fit R(2) = 0.91 ± 0.09). Between younger and older subjects, normalized positions of the R/T boundary, with value 0 at the bone-cartilage interface and 1 at the cartilage surface, were significantly (p < 0.05) different in femoral (0.51 ± 0.12 versus 0.41 ± 0.10), but not in tibial cartilage (0.65 ± 0.11 versus 0.57 ± 0.09, p = 0.119). Within both age groups, differences between femoral and tibial R/T boundaries were significant. Using a fascicle model and angle-sensitive MRI, the depth-dependent anisotropic fiber arrangement of knee cartilage could be assessed in vivo from a single 7 T MR image. The derived quantitative parameter, thickness of the radial zone, may serve as an indicator of the structural integrity of cartilage. This method may potentially be suitable to detect and monitor early osteoarthritis because the progressive disintegration of the anisotropic network is also indicative of arthritic changes in cartilage.
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Affiliation(s)
- Nikita Garnov
- Department of Diagnostic and Interventional Radiology, Leipzig University Hospital, Liebigstrasse 20, Leipzig, Germany
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Garnov N, Busse H, Gründer W. Angle-sensitive MRI for quantitative analysis of fiber-network deformations in compressed cartilage. Magn Reson Med 2013; 70:225-31. [PMID: 23716388 DOI: 10.1002/mrm.24795] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 04/11/2013] [Accepted: 04/14/2013] [Indexed: 11/10/2022]
Abstract
PURPOSE To demonstrate the feasibility of a novel experimental method to quantitatively analyze fiber-network deformation in compressed cartilage by angle-sensitive magnetic resonance imaging (MRI) of cartilage. METHODS Three knee cartilage samples of an adult sheep were imaged in a high-resolution MRI scanner at 7 T. Main fiber orientation and its "offset" from the direction perpendicular to the bone-cartilage boundary were derived from MR images taken at different orientations with respect to B0. Bending of the collagen fibers was determined from weight-bearing MRI with the load (up to 1.0 MPa) applied over the whole sample surface. A "fascicle" model of the cartilage ultrastructure was assumed to analyze characteristic intensity variations in T2-weighted images under load. RESULTS T2-weighted MR images showed a strong variation of the signal intensities with sample orientation. In the T2-weighted weight-bearing series, regions of high signal intensity underwent shifts from the lateral to the central parts in all three cartilage samples. The bending of the collagen fibers was determined to be 27.2°, 35.4°, and 40.0° per MPa, respectively. CONCLUSION Assuming a "fascicle" model, the presented MRI method provides quantitative measures of structural adjustments in compressed cartilage. Our preliminary analysis suggests that cartilage fiber deformation includes both bending and crimping.
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Affiliation(s)
- Nikita Garnov
- Department of Diagnostic and Interventional Radiology Leipzig University Hospital Liebigstrasse 20 Leipzig Germany.
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A review of the combination of experimental measurements and fibril-reinforced modeling for investigation of articular cartilage and chondrocyte response to loading. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2013; 2013:326150. [PMID: 23653665 PMCID: PMC3638701 DOI: 10.1155/2013/326150] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 01/11/2013] [Accepted: 02/23/2013] [Indexed: 11/17/2022]
Abstract
The function of articular cartilage depends on its structure and composition, sensitively impaired in disease (e.g. osteoarthritis, OA). Responses of chondrocytes to tissue loading are modulated by the structure. Altered cell responses as an effect of OA may regulate cartilage mechanotransduction and cell biosynthesis. To be able to evaluate cell responses and factors affecting the onset and progression of OA, local tissue and cell stresses and strains in cartilage need to be characterized. This is extremely challenging with the presently available experimental techniques and therefore computational modeling is required. Modern models of articular cartilage are inhomogeneous and anisotropic, and they include many aspects of the real tissue structure and composition. In this paper, we provide an overview of the computational applications that have been developed for modeling the mechanics of articular cartilage at the tissue and cellular level. We concentrate on the use of fibril-reinforced models of cartilage. Furthermore, we introduce practical considerations for modeling applications, including also experimental tests that can be combined with the modeling approach. At the end, we discuss the prospects for patient-specific models when aiming to use finite element modeling analysis and evaluation of articular cartilage function, cellular responses, failure points, OA progression, and rehabilitation.
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Hanifi A, Bi X, Yang X, Kavukcuoglu B, Lin PC, DiCarlo E, Spencer RG, Bostrom MP, Pleshko N. Infrared fiber optic probe evaluation of degenerative cartilage correlates to histological grading. Am J Sports Med 2012; 40:2853-61. [PMID: 23108637 PMCID: PMC4235670 DOI: 10.1177/0363546512462009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Osteoarthritis (OA), a degenerative cartilage disease, results in alterations of the chemical and structural properties of tissue. Arthroscopic evaluation of full-depth tissue composition is limited and would require tissue harvesting, which is inappropriate in daily routine. Fourier transform infrared (FT-IR) spectroscopy is a modality based on molecular vibrations of matrix components that can be used in conjunction with fiber optics to acquire quantitative compositional data from the cartilage matrix. PURPOSE To develop a model based on infrared spectra of articular cartilage to predict the histological Mankin score as an indicator of tissue quality. STUDY DESIGN Comparative laboratory study. METHODS Infrared fiber optic probe (IFOP) spectra were collected from nearly normal and more degraded regions of tibial plateau articular cartilage harvested during knee arthroplasty (N = 61). Each region was graded using a modified Mankin score. A multivariate partial least squares algorithm using second-derivative spectra was developed to predict the histological modified Mankin score. RESULTS The partial least squares model derived from IFOP spectra predicted the modified Mankin score with a prediction error of approximately 1.4, which resulted in approximately 72% of the Mankin-scored tissues being predicted correctly and 96% being predicted within 1 grade of their true score. CONCLUSION These data demonstrate that IFOP spectral parameters correlate with histological tissue grade and can be used to provide information on tissue composition. CLINICAL RELEVANCE Infrared fiber optic probe studies have significant potential for the evaluation of cartilage tissue quality without the need for tissue harvest. Combined with arthroscopy, IFOP analysis could facilitate the definition of tissue margins in debridement procedures.
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Affiliation(s)
- Arash Hanifi
- Department of Bioengineering, Temple University, Philadelphia, PA 19122
| | - Xiaohong Bi
- Research Division, Hospital for Special Surgery, New York, NY10021
| | - Xu Yang
- Research Division, Hospital for Special Surgery, New York, NY10021
| | - Beril Kavukcuoglu
- Department of Bioengineering, Temple University, Philadelphia, PA 19122
| | - Ping Chang Lin
- The National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - Edward DiCarlo
- Research Division, Hospital for Special Surgery, New York, NY10021
| | - Richard G. Spencer
- The National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | | | - Nancy Pleshko
- Department of Bioengineering, Temple University, Philadelphia, PA 19122
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Seidel T, Hammer N, Garnov N, Schneider G, Steinke H. An algorithm for the calculation of three-dimensional collagen fiber orientation in ligaments using angle-sensitive MRI. Magn Reson Med 2012; 69:1595-602. [PMID: 22826018 DOI: 10.1002/mrm.24408] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/07/2012] [Accepted: 06/18/2012] [Indexed: 11/07/2022]
Abstract
A method based on angle-sensitive magnetic resonance imaging for determining unknown orientations of collagen fibers in ligaments is presented. Collagen fibers were stepwise rotated around two independent axes within a 3T magnetic resonance tomograph (from 0° to 180°, step size=10°). Analyzing the magnetic resonance signal intensity of each voxel as a function of the rotation angle, directions were calculated by means of a computational algorithm. The accuracy of the algorithm was validated using 1000 random test directions, revealing an average deviation of 4.4° (median±standard deviation: 2.7°±9°). Subsequently, the presented method was applied to three specimens of the human iliotibial tract mounted in different directions in a rotatable plastic box. Polarized light microscopy was used to verify parallel alignment of the collagen fibers in the three specimens. The calculated directions were compared with the directions of the specimens. Analyzing each voxel separately, average deviations (median±standard deviation) in the three specimens were: 11.2° (3.6°±20.4°), 12° (5°±24.1°), and 20.4° (8.7°±27°). If the magnetic resonance signal intensity of each voxel was averaged with the intensity of immediately neighboring voxels, average deviations (median±standard deviation) were 8.5° (3.6°±17.4°), 6.2° (0°±18°), and 9.2° (5°±19.2°). The presented method has the potential to be applied in situ to anatomical structures like cartilage, ligaments, tendons and fascia.
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Affiliation(s)
- Thomas Seidel
- Institute of Anatomy, University of Leipzig, and Department of Diagnostic and Interventional Radiology, Leipzig University Hospital, Leipzig, Germany
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Damion RA, Pawaskar SS, Ries ME, Ingham E, Williams S, Jin Z, Radjenovic A. Spin-lattice relaxation rates and water content of freeze-dried articular cartilage. Osteoarthritis Cartilage 2012; 20:184-90. [PMID: 22197886 DOI: 10.1016/j.joca.2011.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 11/14/2011] [Accepted: 12/12/2011] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Nuclear magnetic resonance (NMR) spin-lattice relaxation rates were measured in bovine and porcine articular cartilage as a function of water content. METHODS Water content was varied by freeze-drying samples for short periods of time (up to 15 min). The samples were weighed at all stages of drying so that water content could be quantified. Spin-lattice relaxation rates were measured using magnetic resonance imaging (MRI). RESULTS Linear correlations were observed between relaxation rate and two measures of inverse water content: (1) solid-to-water ratio (ρ), expressed as a ratio of the mass of the solid component of the cartilage (m(s)) and the mass of water at each freeze-drying time point (m(w)), and (2) a ratio of the total mass of the fully-hydrated cartilage and m(w) (1/w). These correlations did not appear significantly different for the bovine and porcine data. However, fitting the data to a piecewise-linear model revealed differences between these two species. We interpret the first two segments of the piecewise model as the depletion of different water phases but conjecture that the third segment is partially caused by changes in relaxation rates as a result of a reduction in macromolecular mobilities. CONCLUSIONS Whilst we can produce linear correlations which broadly describe the dependence of the measured spin-lattice relaxation rate on (inverse) water content, the linear model seems to obscure a more complicated relationship which potentially provides us with more information about the structure of articular cartilage and its extracellular water.
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Affiliation(s)
- R A Damion
- School of Physics & Astronomy, University of Leeds, Leeds LS2 9JT, UK
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Närhi T, Siitonen U, Lehto LJ, Hyttinen MM, Arokoski JPA, Brama PA, Jurvelin JS, Helminen HJ, Julkunen P. Minor influence of lifelong voluntary exercise on composition, structure, and incidence of osteoarthritis in tibial articular cartilage of mice compared with major effects caused by growth, maturation, and aging. Connect Tissue Res 2011; 52:380-92. [PMID: 21405978 DOI: 10.3109/03008207.2010.544428] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We investigated the effects of lifelong voluntary exercise on articular cartilage of mice. At the age of 4 weeks C57BL mice (n = 152) were divided into two groups, with one group serving as a sedentary control whereas the other was allowed free access to a running wheel from the age of 1 month onward. Mice were euthanized at four different time points (1, 2, 6, and 18 months of age). Articular cartilage samples were gathered from the load-bearing area of the tibial medial plateaus, and osteoarthritis was graded. Additionally, the proteoglycan content distribution was assessed using digital densitometry, collagen fibril orientation, and parallelism with polarized light microscopy, and collagen content using Fourier transform infrared imaging spectroscopy. The incidence of osteoarthritis increased with aging, but exercise had no effect on this trend. Furthermore, the structure and composition revealed significant growth, maturation, and age-dependent properties. Exercise exerted a minor effect on collagen fibril orientation in the superficial zone. Fibril orientation at 2 months of age was more perpendicular to surface (p < 0.05) in controls compared with runners, whereas the situation was reversed at the age of 18 months (p < 0.05). The collagen content of the superficial zone was higher (p < 0.01) at the age of 18 months in controls compared with runners but the proteoglycan content did not display any exercise-dependent changes. In conclusion, growth, maturation, and aging exerted a clear effect on integrity, structure, and composition of medial tibial plateau articular cartilage in mice, whereas lifelong voluntary exercise had only a minor effect on collagen architecture and content.
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Affiliation(s)
- Tommi Närhi
- Department of Anatomy, Institute of Biomedicine, University of Eastern Finland , Kuopio , Finland
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Sung MS, Jeong CH, Lim YS, Yoo WJ, Chung SK, Jung NY. Periosteal autograft for articular cartilage defects in dogs: MR imaging and ultrasonography of the repair process. Acta Radiol 2011; 52:181-90. [PMID: 21498347 DOI: 10.1258/ar.2010.100087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Autologous periosteal grafting is used as treatment for cartilage defects. PURPOSE To assess the role of MR imaging and ultrasonography in the evaluation of the post-graft repair process with imaging and histologic correlation. MATERIAL AND METHODS Periosteal grafts obtained from the tibia of eight dogs were transplanted to the experimental cartilage defects in the femoral condyles (15 knees). The control group was comprised of three dogs (five knees). MR imaging using 4.7T and ultrasonography of the grafted specimens was performed at one, two, four, eight, and 16 weeks after transplantation. The animals were sacrificed at the time of imaging at the previously specified intervals. Histologic analysis with imaging correlation was subsequently performed. RESULTS All specimens taken from one to 16 weeks demonstrated periosteal proliferation in the graft. At one week, experimental cartilage defects were no longer present on MR imaging. Area of high signal intensity (SI) in the defect was present which corresponded to hemorrhage, edema, and fibrosis on histology. At two, four, and eight weeks, all but two graft demonstrated heterogeneous high SI on T2-weighted image, consistent with immature cartilage. At 16 weeks, all grafts showed heterogeneous isointense to adjacent cartilage on all sequences, which corresponded to dominant mature cartilage. The repair tissue near the exposed subchondral bone revealed heterogeneous high SI on T2-weighted images. This corresponded to the fibrosis with vascular penetration and edema. In the control group, no cartilage repair was noted within cartilage defects. The serial MR features of the grafted area correlated well with the histologic findings. Serial sonographic findings were not sufficient to provide the regenerated cartilage maturity. CONCLUSION MR imaging is capable of depicting the repair characteristics following periosteal grafting for articular cartilage defects. MR imaging may provide useful information in the assessment of the graft appearance with definite implications regarding the degree and success of incorporation.
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Affiliation(s)
| | - Chang Hoon Jeong
- Department of Orthopedic Surgery, The Catholic University of Korea, College of Medicine, Bucheon St Mary's Hospital, Sosa-dong, Bucheon, Kyunggi-do, 420-717, Korea
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Zheng S, Xia Y, Badar F. Further studies on the anisotropic distribution of collagen in articular cartilage by μMRI. Magn Reson Med 2011; 65:656-63. [PMID: 20939069 PMCID: PMC3021642 DOI: 10.1002/mrm.22648] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 08/16/2010] [Accepted: 08/26/2010] [Indexed: 11/08/2022]
Abstract
To further study the anisotropic distribution of the collagen matrix in articular cartilage, microscopic magnetic resonance imaging experiments were carried out on articular cartilages from the central load-bearing area of three canine humeral heads at 13 μm resolution across the depth of tissue. Quantitative T2 images were acquired when the tissue blocks were rotated, relative to B0, along two orthogonal directions, both perpendicular to the normal axis of the articular surface. The T2 relaxation rate (R2) was modeled, by three fibril structural configurations (solid cone, funnel, and fan), to represent the anisotropy of the collagen fibrils in cartilage from the articular surface to the cartilage/bone interface. A set of complex and depth-dependent characteristics of collagen distribution was found in articular cartilage. In particular, there were two anisotropic components in the superficial zone and an asymmetrical component in the radial zone of cartilage. A complex model of the three-dimensional fibril architecture in articular cartilage is proposed, which has a leaf-like or layer-like structure in the radial zone, arises in a radial manner from the subchondral bone, spreads and arches passing the isotropic transitional zone, and exhibits two distinct anisotropic components (vertical and transverse) in the surface portion of the tissue.
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Affiliation(s)
| | - Yang Xia
- Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI 48309
| | - Farid Badar
- Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI 48309
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Julkunen P, Halmesmäki EP, Iivarinen J, Rieppo L, Närhi T, Marjanen J, Rieppo J, Arokoski J, Brama PA, Jurvelin JS, Helminen HJ. Effects of growth and exercise on composition, structural maturation and appearance of osteoarthritis in articular cartilage of hamsters. J Anat 2010; 217:262-74. [PMID: 20646109 DOI: 10.1111/j.1469-7580.2010.01270.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Articular cartilage composition and structure are maintained and remodeled by chondrocytes under the influence of loading. Exercise-induced changes in the composition, structure, mechanical properties and tissue integrity of growing and aging hamster articular cartilage were investigated. Articular cartilage samples (n = 191) were harvested from the proximal tibiae of hamsters aged 1, 3, 6, 12 and 15 months. The hamsters were divided into runners and controls. The runners had free access to a running wheel between 1 and 3 months (runner groups 3-, 12- and 15-month-old hamsters) or 1 and 6 months (runner group 6-month-old hamsters) of age. Control animals were subjected to a sedentary lifestyle. Mechanical indentation tests and depth-wise compositional and structural analyses were performed for the cartilage samples. Furthermore, the integrity of articular cartilage was assessed using histological osteoarthritis grading. Exercise affected the collagen network organization after a 5-month exercise period, especially in the middle and deep zones. However, no effect on the mechanical properties was detected after exercise. Before the age of 12 months, the runners showed less osteoarthritis than the controls, whereas at 15 months of age the situation was reversed. It is concluded that, in hamsters, physical exercise at a young age enhances cartilage maturation and alters the depth-wise cartilage structure and composition. This may be considered beneficial. However, exercise at a young age demonstrated adverse effects on cartilage at a later age with a significant increase in the incidence of osteoarthritis.
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Affiliation(s)
- Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.
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van Turnhout MC, Schipper H, Engel B, Buist W, Kranenbarg S, van Leeuwen JL. Postnatal development of collagen structure in ovine articular cartilage. BMC DEVELOPMENTAL BIOLOGY 2010; 10:62. [PMID: 20529268 PMCID: PMC2906441 DOI: 10.1186/1471-213x-10-62] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 06/07/2010] [Indexed: 12/01/2022]
Abstract
Background Articular cartilage (AC) is the layer of tissue that covers the articulating ends of the bones in diarthrodial joints. Across species, adult AC shows an arcade-like structure with collagen predominantly perpendicular to the subchondral bone near the bone, and collagen predominantly parallel to the articular surface near the articular surface. Recent studies into collagen fibre orientation in stillborn and juvenile animals showed that this structure is absent at birth. Since the collagen structure is an important factor for AC mechanics, the absence of the adult Benninghoff structure has implications for perinatal AC mechanobiology. The current objective is to quantify the dynamics of collagen network development in a model animal from birth to maturity. We further aim to show the presence or absence of zonal differentiation at birth, and to assess differences in collagen network development between different anatomical sites of a single joint surface. We use quantitative polarised light microscopy to investigate properties of the collagen network and we use the sheep (Ovis aries) as our model animal. Results Predominant collagen orientation is parallel to the articular surface throughout the tissue depth for perinatal cartilage. This remodels to the Benninghoff structure before the sheep reach sexual maturity. Remodelling of predominant collagen orientation starts at a depth just below the future transitional zone. Tissue retardance shows a minimum near the articular surface at all ages, which indicates the presence of zonal differentiation at all ages. The absolute position of this minimum does change between birth and maturity. Between different anatomical sites, we find differences in the dynamics of collagen remodelling, but no differences in adult collagen structure. Conclusions The collagen network in articular cartilage remodels between birth and sexual maturity from a network with predominant orientation parallel to the articular surface to a Benninghoff network. The retardance minimum near, but not at, the articular surface at all ages shows that a zonal differentiation is already present in the perinatal animals. In these animals, the zonal differentiation can not be correlated to the collagen network orientation. We find no difference in adult collagen structure in the nearly congruent metacarpophalangeal joint, but we do find differences in the dynamics of collagen network remodelling.
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Affiliation(s)
- Mark C van Turnhout
- Wageningen University, Department of Animal Sciences, Experimental Zoology Group, 6700 AH Wageningen, the Netherlands.
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Contribution of postnatal collagen reorientation to depth-dependent mechanical properties of articular cartilage. Biomech Model Mechanobiol 2010; 10:269-79. [PMID: 20526790 DOI: 10.1007/s10237-010-0233-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 05/20/2010] [Indexed: 10/19/2022]
Abstract
The collagen fibril network is an important factor for the depth-dependent mechanical behaviour of adult articular cartilage (AC). Recent studies show that collagen orientation is parallel to the articular surface throughout the tissue depth in perinatal animals, and that the collagen orientations transform to a depth-dependent arcade-like structure in adult animals. Current understanding on the mechanobiology of postnatal AC development is incomplete. In the current paper, we investigate the contribution of collagen fibril orientation changes to the depth-dependent mechanical properties of AC. We use a composition-based finite element model to simulate in a 1-D confined compression geometry the effects of ten different collagen orientation patterns that were measured in developing sheep. In initial postnatal life, AC is mostly subject to growth and we observe only small changes in depth-dependent mechanical behaviour. Functional adaptation of depth-dependent mechanical behaviour of AC takes place in the second half of life before puberty. Changes in fibril orientation alone increase cartilage stiffness during development through the modulation of swelling strains and osmotic pressures. Changes in stiffness are most pronounced for small stresses and for cartilage adjacent to the bone. We hypothesize that postnatal changes in collagen fibril orientation induce mechanical effects that in turn promote these changes. We further hypothesize that a part of the depth-dependent postnatal increase in collagen content in literature is initiated by the depth-dependent postnatal increase in fibril strain due to collagen fibril reorientation.
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Goebel JC, Bolbos R, Pham M, Galois L, Rengle A, Loeuille D, Netter P, Gillet P, Beuf O, Watrin-Pinzano A. In vivo high-resolution MRI (7T) of femoro-tibial cartilage changes in the rat anterior cruciate ligament transection model of osteoarthritis: a cross-sectional study. Rheumatology (Oxford) 2010; 49:1654-64. [PMID: 20488927 DOI: 10.1093/rheumatology/keq154] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE To assess OA-related changes in mean compartmental femorotibial cartilage thickness in rat knees by three-dimensional (3D) MRI (7T). METHODS MRI was performed in vivo at 7T on OA and untouched contralateral knee joints. Gradient Echo Fast Imaging 3D MR images were acquired sequentially in surgically induced OA (D0) in 40 Wistar rats (anterior cruciate ligament transection). Mean femoral (trochlear, lateral and medial) and tibial (lateral and medial) cartilage thicknesses were quantified from a 2D MRI slide in weight-bearing areas and from a 3D MRI data set. At each time-point [Day (D)8, D14, D21, D40 and D60], eight animals (16 knees) were sacrificed for concomitant histomorphometry. RESULTS As body weight dramatically increased throughout the experiment (+150%, baseline vs endpoint), all compartmental mean cartilage thicknesses noticeably decreased (D8, D14) and then remained relatively stable. Femoral compartments in OA knees were thinner at the end of the experiment than in contralateral age-matched knees. Conversely, lateral and medial tibial cartilages were thicker than controls. Histological correlation was significant only in untouched healthy cartilages (3D better than 2D). CONCLUSIONS 3D MRI (7T) enables in vivo monitoring of compartmental changes in OA-related femorotibial rat cartilage thickness vs contralateral age-matched knees.
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Affiliation(s)
- Jean C Goebel
- UMR 7561 CNRS - Nancy University, Physiopathologie, Pharmacologie et Ingénierie Articulaires, Faculté de Médecine de Nancy, BP 184, Avenue de la Foret de Haye, F54505 Vandoeuvre, France
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Julkunen P, Iivarinen J, Brama PA, Arokoski J, Jurvelin JS, Helminen HJ. Maturation of collagen fibril network structure in tibial and femoral cartilage of rabbits. Osteoarthritis Cartilage 2010; 18:406-15. [PMID: 19941998 DOI: 10.1016/j.joca.2009.11.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 11/04/2009] [Accepted: 11/09/2009] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The structure and composition of articular cartilage change during development and growth, as well as in response to varying loading conditions. These changes modulate the functional properties of cartilage. We studied maturation-related changes in the collagen network organization of cartilage as a function of tissue depth. DESIGN Articular cartilage from the tibial medial plateaus and femoral medial condyles of female New Zealand white rabbits was collected from six age-groups: 4 weeks (n=30), 6 weeks (n=30), 3 months (n=24), 6 months (n=24), 9 months (n=27) and 18 months (n=19). Collagen fibril orientation, parallelism (anisotropy) and optical retardation were analyzed with polarized light microscopy. Differences in the development of depth-wise collagen organization in consecutive age-groups and the two joint locations were compared statistically. RESULTS The collagen fibril network of articular cartilage undergoes significant changes during maturation. The most prominent changes in collagen architecture, as assessed by orientation, parallelism and retardation were noticed between the ages of 4 and 6 weeks in tibial cartilage and between 6 weeks and 3 months in femoral cartilage, i.e., orientation became more perpendicular-to-surface, and parallelism and retardation increased with changes being most prominent in the deep zone. At the age of 6 weeks, tibial cartilage had a more perpendicular-to-surface orientation in the middle and deep zones than femoral cartilage (P<0.001) and higher parallelism throughout the tissue depth (P<0.001), while femoral cartilage exhibited more parallel-to-surface orientation (P<0.01) above the deep zone after maturation. Optical retardation of collagen was higher in tibial than in femoral cartilage at the ages of 4 and 6 weeks (P<0.001), while at older ages, retardation below the superficial zone in the femoral cartilage became higher than in the tibial cartilage. CONCLUSIONS During maturation, there is a significant modulation of collagen organization in articular cartilage which occurs earlier in tibial than in femoral cartilage, and is most pronounced in the deep zone.
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Affiliation(s)
- P Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.
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Julkunen P, Harjula T, Iivarinen J, Marjanen J, Seppänen K, Närhi T, Arokoski J, Lammi MJ, Brama PA, Jurvelin JS, Helminen HJ. Biomechanical, biochemical and structural correlations in immature and mature rabbit articular cartilage. Osteoarthritis Cartilage 2009; 17:1628-38. [PMID: 19615962 DOI: 10.1016/j.joca.2009.07.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 06/18/2009] [Accepted: 07/02/2009] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The structure and composition of articular cartilage change during development and growth. These changes lead to alterations in the mechanical properties of cartilage. In the present study, biomechanical, biochemical and structural relationships of articular cartilage during growth and maturation of rabbits are investigated. DESIGN Articular cartilage specimens from the tibial medial plateaus and femoral medial condyles of female New Zealand white rabbits were collected from seven age-groups; 0 days (n=29), 11 days (n=30), 4 weeks (n=30), 6 weeks (n=30), 3 months (n=24), 6 months (n=24) and 18 months (n=19). The samples underwent mechanical testing under creep indentation. From the mechanical response, instantaneous and equilibrium moduli were determined. Biochemical analyses of tissue collagen, hydroxylysylpyridinoline (HP) and pentosidine (PEN) cross-links in full thickness cartilage samples were conducted. Proteoglycans were investigated depth-wise from the tissue sections by measuring the optical density of Safranin-O-stained samples. Furthermore, depth-wise collagen architecture of articular cartilage was analyzed with polarized light microscopy. Finite element analyses of the samples from different age-groups were conducted to reveal tensile and compressive properties of the fibril network and the matrix of articular cartilage, respectively. RESULTS Tissue thickness decreased from approximately 3 to approximately 0.5mm until the age of 3 months, while the instantaneous modulus increased with age prior to peak at 4-6 weeks. A lower equilibrium modulus was observed before 3-month-age, after which the equilibrium modulus continued to increase. Collagen fibril orientation angle and parallelism index were inversely related to the instantaneous modulus, tensile fibril modulus and tissue thickness. Collagen content and cross-linking were positively related to the equilibrium compressive properties of the tissue. CONCLUSIONS During maturation, significant modulation of tissue structure, composition and mechanical properties takes place. Importantly, the present study provides insight into the mechanical, chemical and structural interactions that lead to functional properties of mature articular cartilage.
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Affiliation(s)
- P Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.
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Biomechanical and biochemical characteristics of the mandibular condylar cartilage. Osteoarthritis Cartilage 2009; 17:1408-15. [PMID: 19477310 DOI: 10.1016/j.joca.2009.04.025] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 04/16/2009] [Accepted: 04/29/2009] [Indexed: 02/02/2023]
Abstract
The human masticatory system consists of a mandible which is able to move with respect to the skull at its bilateral temporomandibular joint (TMJ) through contractions of the masticatory muscles. Like other synovial joints, the TMJ is loaded mechanically during function. The articular surface of the mandibular condyle is covered with cartilage that is composed mainly of collagen fibers and proteoglycans. This construction results in a viscoelastic response to loading and enables the cartilage to play an important role as a stress absorber during function. To understand its mechanical functions properly, and to assess its limitations, detailed information about the viscoelastic behavior of the mandibular condylar cartilage is required. The purpose of this paper is to review the fundamental concepts of the biomechanical behavior of the mandibular condylar cartilage. This review consists of four parts. Part 1 is a brief introduction of the structure and function of the mandibular condylar cartilage. In Part 2, the biochemical composition of the mandibular condylar cartilage is summarized. Part 3 explores the biomechanical properties of the mandibular condylar cartilage. Finally, Part 4 relates this behavior to the breakdown mechanism of the mandibular condylar cartilage which is associated with the progression of osteoarthritis in the TMJ.
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Zheng S, Xia Y. The collagen fibril structure in the superficial zone of articular cartilage by microMRI. Osteoarthritis Cartilage 2009; 17:1519-28. [PMID: 19527808 PMCID: PMC2763952 DOI: 10.1016/j.joca.2009.05.013] [Citation(s) in RCA: 23] [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: 03/02/2009] [Revised: 05/11/2009] [Accepted: 05/24/2009] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate the fibril architecture of the collagen matrix in the superficial zone (SZ) of articular cartilage non-destructively by microscopic magnetic resonance imaging (microMRI) T(2) anisotropy. METHOD Six specimens of canine humeral cartilage were rotated in such a way that the normal axis of the articular surface of the cartilage specimen remained stationary and perpendicular to the static magnetic field, over a range of 180 degrees and at a step of 15 degrees. At each rotation angle, a quantitative T(2) image was constructed at 13 microm pixel resolution. RESULTS A set of complex and depth-dependent patterns was found in the microMRI T(2) anisotropy along the depth of the tissue. In the SZ, the T(2) anisotropy is clearly periodic, which demonstrates that the distribution of the collagen fibrils in the SZ is not random. In the transitional zone, the periodicity of the T(2) anisotropy approximately doubles with respect to that in the SZ. In the initial part of the radial zone (RZ), the T(2) anisotropy is also periodic but inverse to that in the SZ. In the deep part of the RZ, the T(2) anisotropy becomes increasingly weaker and eventually disappears. CONCLUSION There exists a certain degree of collagen anisotropy in all zones of articular cartilage. The anisotropic imaging data can be interpreted with the aid of a collagen architecture model.
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Affiliation(s)
- ShaoKuan Zheng
- Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI 48309
| | - Yang Xia
- Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI 48309
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Raya JG, Horng A, Dietrich O, Weber J, Dinges J, Mützel E, Reiser MF, Glaser C. Voxel-based reproducibility of T2 relaxation time in patellar cartilage at 1.5 T with a new validated 3D rigid registration algorithm. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2009; 22:229-39. [DOI: 10.1007/s10334-009-0168-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 03/03/2009] [Accepted: 03/11/2009] [Indexed: 11/29/2022]
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Rieppo J, Hyttinen MM, Halmesmaki E, Ruotsalainen H, Vasara A, Kiviranta I, Jurvelin JS, Helminen HJ. Changes in spatial collagen content and collagen network architecture in porcine articular cartilage during growth and maturation. Osteoarthritis Cartilage 2009; 17:448-55. [PMID: 18849174 DOI: 10.1016/j.joca.2008.09.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 09/02/2008] [Indexed: 02/02/2023]
Abstract
OBJECTIVES The present study was designed to reveal changes in the collagen network architecture and collagen content in cartilage during growth and maturation of pigs. METHODS Femoral groove articular cartilage specimens were collected from 4-, 11- and 21-month-old domestic pigs (n=12 in each group). The animal care conditions were kept constant throughout the study. Polarized light microscopy was used to determine the collagen fibril network birefringence, fibril orientation and parallelism. Infrared spectroscopy was used to monitor changes in the spatial collagen content in cartilage tissue. RESULTS During growth, gradual alterations were recorded in the collagen network properties. At 4 months of age, a major part of the collagen fibrils was oriented parallel to the cartilage surface throughout the tissue. However, the fibril orientation changed considerably as skeletal maturation progressed. At 21 months of age, the fibrils of the deep zone cartilage ran predominantly at right angles to the cartilage surface. The collagen content increased and its depthwise distribution changed during growth and maturation. A significant increase of the collagen network birefringence was observed in the deep tissue at the age of 21 months. CONCLUSIONS The present study revealed dynamic changes of the collagen network during growth and maturation of the pigs. The structure of the collagen network of young pigs gradually approached a network with the classical Benninghoff architecture. The probable explanation for the alterations is growth of the bone epiphysis with simultaneous adaptation of the cartilage to increased joint loading. The maturation of articular cartilage advances gradually with age and offers, in principle, the possibility to influence the quality of the tissue, especially by habitual joint loading. These observations in porcine cartilage may be of significance with respect to the maturation of human articular cartilage.
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Affiliation(s)
- J Rieppo
- Institute of Biomedicine, Anatomy, University of Kuopio, Kuopio, Finland
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MR imaging of cartilage and its repair in the knee - a review. Eur Radiol 2009; 19:1582-94. [DOI: 10.1007/s00330-009-1352-3] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 01/20/2009] [Accepted: 01/26/2009] [Indexed: 02/07/2023]
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Katta J, Jin Z, Ingham E, Fisher J. Biotribology of articular cartilage--a review of the recent advances. Med Eng Phys 2008; 30:1349-63. [PMID: 18993107 DOI: 10.1016/j.medengphy.2008.09.004] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 09/17/2008] [Accepted: 09/22/2008] [Indexed: 11/24/2022]
Abstract
A brief review of the advances in the biotribology of articular cartilage in the last decade or so are presented. The review is limited to experimental friction and wear studies involving articular cartilage. The importance of developing in vitro models as tools not only to understand the cartilage tribological characteristics, but to evaluate current and future cartilage substitution and treatment therapies is discussed.
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Affiliation(s)
- Jayanth Katta
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, West Yorkshire LS2 9JT, UK
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Abstract
Recent technical developments in high-field magnetic resonance (MR) scanners, improvement in radio frequency coil design and gradient performance along with the development of efficient pulse sequences and new methods of enhancing contrast have made high-quality imaging of animal arthritis models feasible. MR can provide high-resolution structural information about the osteoarthritic changes in animal models, and also information about the biophysical properties of cartilage. This paper reviews the MR techniques available for animal knee imaging, and the various MR-derived readouts of knee osteoarthritis in animal models. Pitfalls in interpreting animal joint anatomy and joint composition are highlighted.
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Affiliation(s)
- Yi-Xiang Wang
- Department of Radiology, The Chinese University of Hong Kong, Hong Kong, China.
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