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Cari M Whyne - One of the best experts on this subject based on the ideXlab platform.

  • high resolution Bone Material Property assignment yields robust subject specific finite element models of complex thin Bone structures
    Journal of Biomechanics, 2016
    Co-Authors: Amirreza Pakdel, Jeffrey A Fialkov, Cari M Whyne
    Abstract:

    Accurate finite element (FE) modeling of complex skeletal anatomy requires high resolution in both meshing and the heterogeneous mapping of Material properties onto the generated mesh. This study introduces Node-based elastic Modulus Assignment with Partial-volume correction (NMAP) as a new approach for FE Material Property assignment to thin Bone structures. The NMAP approach incorporates point spread function based deblurring of CT images, partial-volume correction of CT image voxel intensities and anisotropic interpolation and mapping of CT intensity assignment to FE mesh nodes. The NMAP procedure combined with a derived craniomaxillo-facial skeleton (CMFS) specific density-isotropic elastic modulus relationship was applied to produce specimen-specific FE models of 6 cadaveric heads. The NMAP procedure successfully generated models of the complex thin Bone structures with surface elastic moduli reflective of cortical Bone Material properties. The specimen-specific CMFS FE models were able to accurately predict experimental strains measured under in vitro temporalis and masseter muscle loading (r=0.93, slope=1.01, n=5). The strength of this correlation represents a robust validation for CMFS FE modeling that can be used to better understand load transfer in this complex musculoskeletal system. The developed methodology offers a systematic process-flow able to address the complexity of the CMFS that can be further applied to create high-fidelity models of any musculoskeletal anatomy.

Amirreza Pakdel - One of the best experts on this subject based on the ideXlab platform.

  • high resolution Bone Material Property assignment yields robust subject specific finite element models of complex thin Bone structures
    Journal of Biomechanics, 2016
    Co-Authors: Amirreza Pakdel, Jeffrey A Fialkov, Cari M Whyne
    Abstract:

    Accurate finite element (FE) modeling of complex skeletal anatomy requires high resolution in both meshing and the heterogeneous mapping of Material properties onto the generated mesh. This study introduces Node-based elastic Modulus Assignment with Partial-volume correction (NMAP) as a new approach for FE Material Property assignment to thin Bone structures. The NMAP approach incorporates point spread function based deblurring of CT images, partial-volume correction of CT image voxel intensities and anisotropic interpolation and mapping of CT intensity assignment to FE mesh nodes. The NMAP procedure combined with a derived craniomaxillo-facial skeleton (CMFS) specific density-isotropic elastic modulus relationship was applied to produce specimen-specific FE models of 6 cadaveric heads. The NMAP procedure successfully generated models of the complex thin Bone structures with surface elastic moduli reflective of cortical Bone Material properties. The specimen-specific CMFS FE models were able to accurately predict experimental strains measured under in vitro temporalis and masseter muscle loading (r=0.93, slope=1.01, n=5). The strength of this correlation represents a robust validation for CMFS FE modeling that can be used to better understand load transfer in this complex musculoskeletal system. The developed methodology offers a systematic process-flow able to address the complexity of the CMFS that can be further applied to create high-fidelity models of any musculoskeletal anatomy.

Jeffrey A Fialkov - One of the best experts on this subject based on the ideXlab platform.

  • high resolution Bone Material Property assignment yields robust subject specific finite element models of complex thin Bone structures
    Journal of Biomechanics, 2016
    Co-Authors: Amirreza Pakdel, Jeffrey A Fialkov, Cari M Whyne
    Abstract:

    Accurate finite element (FE) modeling of complex skeletal anatomy requires high resolution in both meshing and the heterogeneous mapping of Material properties onto the generated mesh. This study introduces Node-based elastic Modulus Assignment with Partial-volume correction (NMAP) as a new approach for FE Material Property assignment to thin Bone structures. The NMAP approach incorporates point spread function based deblurring of CT images, partial-volume correction of CT image voxel intensities and anisotropic interpolation and mapping of CT intensity assignment to FE mesh nodes. The NMAP procedure combined with a derived craniomaxillo-facial skeleton (CMFS) specific density-isotropic elastic modulus relationship was applied to produce specimen-specific FE models of 6 cadaveric heads. The NMAP procedure successfully generated models of the complex thin Bone structures with surface elastic moduli reflective of cortical Bone Material properties. The specimen-specific CMFS FE models were able to accurately predict experimental strains measured under in vitro temporalis and masseter muscle loading (r=0.93, slope=1.01, n=5). The strength of this correlation represents a robust validation for CMFS FE modeling that can be used to better understand load transfer in this complex musculoskeletal system. The developed methodology offers a systematic process-flow able to address the complexity of the CMFS that can be further applied to create high-fidelity models of any musculoskeletal anatomy.

L Y Dai - One of the best experts on this subject based on the ideXlab platform.

  • spinal cord injury causes more damage to Bone mass Bone structure biomechanical properties and Bone metabolism than sciatic neurectomy in young rats
    Osteoporosis International, 2006
    Co-Authors: Shengdan Jiang, Leisheng Jiang, L Y Dai
    Abstract:

    Although both spinal cord injury (SCI) and sciatic neurectomy (NX) can cause osteopaenia in young rats, the effects of these two injuries on cortical and cancellous Bone may differ. The objective of this study was to compare the effects of SCI and NX on Bone weight, Bone Material Property, Bone mass, Bone geometry, trabecular microarchitecture, mechanical strength and Bone turnover in young rats. Thirty six-week-old male Sprague-Dawley rats were randomised into three groups (10 per group): SCI, bilateral sciatic NX and untreated control (CON). All rats were killed on day 21. Bone mineral density (BMD) was studied using dual-energy X-ray absorptiometry (DXA). At death, the right proximal tibial metaphysis and the fourth lumbar vertebra were examined for Bone structural geometric analysis by micro-computed tomography (CT) and then processed for histomorphometry to assess Bone cell activity. Serum N-terminal telopeptide of type I collagen (NTX) and osteocalcin (OC) levels were analysed by enzyme-linked immunosorbent assay (ELISA). Biomechanical strength properties of the femur and humerus were measured by three-point bending, and the third lumbar vertebra and the proximal end of tibia were tested by compression. BMD in the sublesional areas of SCI rats was significantly lower than that of NX rats (proximal tibia, 0.176±0.018 g/cm2 vs. 0.224±0.015 g/cm2, P<0.001). Bone volume (BV/TV), trabecular number (Tb.N) and thickness (Tb.Th) in the tibial second spongiosa of SCI rats were significantly less than those in NX rats (BV/TV: 7.15±1.18% vs. 12.32±1.83%, P<0.001; Tb.N: 1.23±0.22 vs. 2.38±0.45, P<0.001; Tb.Th: 33.73±5.15 μm vs. 42.80±7.44 μm, P<0.01) and trabecular separation (Tb.Sp: 1,053.37±164.24 μm vs. 748.32±129.36 μm, P<0.01) was significantly greater than in NX rats. Furthermore, poorer trabecular connectivity was found in SCI rats than in NX rats (number of nodes, N.Nd/TV: 1.04±0.09 vs. 3.29±0.53; number of terminus, N.Tm/TV: 28.53±3.17 vs. 21.64±2.31, P<0.01). The Bone formation rate of the tibial second spongiosa in SCI rats was significantly higher than in NX rats (2.06±0.13 vs. 1.53±0.09, P<0.001) and, also, the eroded surface in SCI rats was significantly higher than in NX rats (13.42±1.24 vs. 10.36±1.07, P<0.001). In addition, biomechanical tests showed that SCI rats had poorer biomechanical properties of the femur, proximal tibia and fourth lumbar vertebra than in NX rats. There were significantly higher levels of OC in SCI rats compared with NX rats (30.19±1.17 vs. 21.15±1.76, P<0.001). Also, serum NTX levels were significantly higher than in NX rats (51.60±2.61 vs. 33.85±1.93, P<0.001). SCI caused more damage to Bone mass, Bone structure, biomechanical properties and Bone metabolism than NX in young rats. This suggests that different mechanisms may underlie osteopaenia following SCI and NX.

Shengdan Jiang - One of the best experts on this subject based on the ideXlab platform.

  • spinal cord injury causes more damage to Bone mass Bone structure biomechanical properties and Bone metabolism than sciatic neurectomy in young rats
    Osteoporosis International, 2006
    Co-Authors: Shengdan Jiang, Leisheng Jiang, L Y Dai
    Abstract:

    Although both spinal cord injury (SCI) and sciatic neurectomy (NX) can cause osteopaenia in young rats, the effects of these two injuries on cortical and cancellous Bone may differ. The objective of this study was to compare the effects of SCI and NX on Bone weight, Bone Material Property, Bone mass, Bone geometry, trabecular microarchitecture, mechanical strength and Bone turnover in young rats. Thirty six-week-old male Sprague-Dawley rats were randomised into three groups (10 per group): SCI, bilateral sciatic NX and untreated control (CON). All rats were killed on day 21. Bone mineral density (BMD) was studied using dual-energy X-ray absorptiometry (DXA). At death, the right proximal tibial metaphysis and the fourth lumbar vertebra were examined for Bone structural geometric analysis by micro-computed tomography (CT) and then processed for histomorphometry to assess Bone cell activity. Serum N-terminal telopeptide of type I collagen (NTX) and osteocalcin (OC) levels were analysed by enzyme-linked immunosorbent assay (ELISA). Biomechanical strength properties of the femur and humerus were measured by three-point bending, and the third lumbar vertebra and the proximal end of tibia were tested by compression. BMD in the sublesional areas of SCI rats was significantly lower than that of NX rats (proximal tibia, 0.176±0.018 g/cm2 vs. 0.224±0.015 g/cm2, P<0.001). Bone volume (BV/TV), trabecular number (Tb.N) and thickness (Tb.Th) in the tibial second spongiosa of SCI rats were significantly less than those in NX rats (BV/TV: 7.15±1.18% vs. 12.32±1.83%, P<0.001; Tb.N: 1.23±0.22 vs. 2.38±0.45, P<0.001; Tb.Th: 33.73±5.15 μm vs. 42.80±7.44 μm, P<0.01) and trabecular separation (Tb.Sp: 1,053.37±164.24 μm vs. 748.32±129.36 μm, P<0.01) was significantly greater than in NX rats. Furthermore, poorer trabecular connectivity was found in SCI rats than in NX rats (number of nodes, N.Nd/TV: 1.04±0.09 vs. 3.29±0.53; number of terminus, N.Tm/TV: 28.53±3.17 vs. 21.64±2.31, P<0.01). The Bone formation rate of the tibial second spongiosa in SCI rats was significantly higher than in NX rats (2.06±0.13 vs. 1.53±0.09, P<0.001) and, also, the eroded surface in SCI rats was significantly higher than in NX rats (13.42±1.24 vs. 10.36±1.07, P<0.001). In addition, biomechanical tests showed that SCI rats had poorer biomechanical properties of the femur, proximal tibia and fourth lumbar vertebra than in NX rats. There were significantly higher levels of OC in SCI rats compared with NX rats (30.19±1.17 vs. 21.15±1.76, P<0.001). Also, serum NTX levels were significantly higher than in NX rats (51.60±2.61 vs. 33.85±1.93, P<0.001). SCI caused more damage to Bone mass, Bone structure, biomechanical properties and Bone metabolism than NX in young rats. This suggests that different mechanisms may underlie osteopaenia following SCI and NX.