Development and Validation of an Older Occupant Finite Element Model of a Mid-Sized Male for Investigation of Age-related Injury Risk

Schoell, Samantha L.; Weaver, Ashley A.; Urban, Jillian E.; Jones, Derek A.; Stitzel, Joel D.; Hwang, Eun Ju; Reed, Matthew P.; Rupp, Jonathan D.; Hu, Jingwen

doi:10.4271/2015-22-0014

Cited by 25 publications

(17 citation statements)

References 69 publications

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“…Thin-plate spline radial basis function interpolation with a relaxation algorithm was used to morph existing atlas FE models of the Global Human Body Models Consortium M50-O v4.4 femur and the Total Human Model for Safety AM50 v4.02 lumbar spine to each subject-specific geometry. (42,(46)(47)(48)(49) Homologous landmarks collected using image segmentation and registration from analogous locations in the atlas and subject-specific geometries were used to derive an interpolation function and coefficients to morph the atlas FE models' nodal coordinates to each subject geometry. (50) Subject-specific vBMD (r CT ) was used to adjust the elastic modulus of the femoral cortex [E, GPa; Equation (1)] (51,52) and vertebral trabecular bone [E, MPa; Equation (2)] (53) in the FE models.…”

Section: Biomarkers Of Bone Turnovermentioning

confidence: 99%

Effect of Exercise Modality During Weight Loss on Bone Health in Older Adults With Obesity and Cardiovascular Disease or Metabolic Syndrome: A Randomized Controlled Trial

Beavers

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Weaver

et al. 2018

Journal of Bone and Mineral Research

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The objective of this study was to determine the ability of either aerobic or resistance training to counter weight-loss-associated bone loss in older adults. There were 187 older adults (67 years, 70% women, 64% white) with obesity (BMI = 34.5 ± 3.7 kg/m ) and cardiovascular disease and/or metabolic syndrome who were randomized to participate in an 18-month, community-based trial, with a follow-up assessment at 30 months. Intervention arms included: weight loss alone (WL; 7% to 10% baseline weight), WL plus aerobic training (WL + AT), and WL plus resistance training (WL + RT), as well as DXA-acquired total hip, femoral neck, and lumbar spine areal bone mineral density (aBMD), and trabecular bone score (TBS). Biomarkers of bone turnover (procollagen type 1 N-terminal propeptide, C-terminal telopeptide of type 1 collagen) were measured at baseline, 6, 18, and 30 (aBMD and TBS only) months. CT-acquired hip and spine volumetric BMD (vBMD), cortical thickness, and bone strength were measured in a subset at baseline (n = 55) and 18 months. Total hip aBMD was reduced by 2% in all groups at 18 months, with a primary analysis showing no significant treatment effects for any DXA, biomarker, or CT outcome. After adjustment for WL and follow-up at 30 months, secondary analyses revealed that total hip [-0.018 (-0.023 to -0.012) g/cm versus -0.025 (-0.031 to -0.019) g/cm ; p = 0.05] and femoral neck [-0.01 (-0.009 to 0.008) g/cm versus -0.011 (-0.020 to -0.002) g/cm ; p = 0.06] aBMD estimates were modestly attenuated in the WL + RT group compared with the WL group. Additionally, lumbar spine aBMD was increased in the WL [0.015 (0.007 to 0.024) g/cm ] and the WL + RT [0.009 (0.000 to 0.017) g/cm ] groups compared with the WL + AT [-0.003 (-0.012 to 0.005)g/cm ] group; both p ≤ 0.01. Community-based exercise does not prevent bone loss during active WL in older adults; however, adding RT may help minimize long-term hip bone loss. © 2018 American Society for Bone and Mineral Research.

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Section: Biomarkers Of Bone Turnovermentioning

confidence: 99%

Effect of Exercise Modality During Weight Loss on Bone Health in Older Adults With Obesity and Cardiovascular Disease or Metabolic Syndrome: A Randomized Controlled Trial

Beavers

Walkup

Weaver

et al. 2018

Journal of Bone and Mineral Research

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“…With the application of this technique, detailed human body models can be constructed and validated to improve the accuracy of injury prediction in computational simulation of thoracic trauma. Specific age-based models that have been developed can be improved by incorporating accurate rib cortical thickness data collected from clinical-CT scans [16,18,21,22,46]. A clinical application of the CDM algorithm would be to apply the methods presented to a wide range of ages and regress rib cortical thickness with age and use the results to improve existing age-based regression functions in the literature [47].…”

Section: Discussionmentioning

confidence: 99%

“…Finite element (FE) human body models have been developed to better understand the injury mechanisms leading to rib fractures [19,20]. Several age-specific thoracic FE models incorporate material properties and geometries representing young adults versus older adults [16,18,21,22]. Most FE models use simplified cortical shells with constant thickness even though rib cortical thickness varies by anatomical region (anterior, lateral, and posterior) and cross-sectional quadrant (superior, interior, inferior, and exterior) [26–35].…”

Section: Introductionmentioning

confidence: 99%

Comparing rib cortical thickness measurements from computed tomography (CT) and Micro-CT

Hostetler

Stitzel

Weaver

2019

Computers in Biology and Medicine

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Background: The objective of this study was to compare cortical thickness of rib specimens scanned with clinical computed tomography (clinical-CT) at 0.5 and 1.0 mm slice thickness versus micro-CT at 0.05 mm slice thickness. Cortical thickness variation and accuracy was explored by anatomical region (anterior vs. lateral) and cross-sectional quadrants (superior, interior, inferior, and exterior). Methods: A validated cortical thickness algorithm was applied to clinical-CT and micro-CT scans of 17 rib specimens from six male post mortem human subjects aged 42–81 years. Each rib specimen was segmented and the thickness measurements were partitioned into cross-sectional quadrants in the anterior and lateral regions of the rib. Within each rib quadrant, the following were calculated: average thickness ± standard deviation, mean thickness difference between clinical-CT and micro-CT, and a thickness ratio between clinical-CT and micro-CT. Correlations from linear regression and paired-t tests were determined for paired clinical-CT and micro-CT results. Results: On average, the 0.5 mm clinical-CT underestimated the micro-CT thickness by 0.005 mm, while the 1.0 mm clinical-CT overestimated the micro-CT thickness by 0.149 mm. Thickness derived from 0.5 mm clinical-CT showed greater significant linear correlations (p < 0.05) with micro-CT thickness compared to 1.0 mm clinical-CT. Conclusions: The small mean differences and thickness ratios near 1 show validation for the cortical thickness algorithm when applied to rib clinical-CT scans. Using clinical-CT scans as way to accurately measure rib cortical thickness offers a non-invasive way to analyze millions of CT scans collected each year from males and females of all ages.

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“…Subject-specific FE models of the proximal femur were developed using morphing techniques to accelerate the development of the models as described by previous literature [ 27 – 30 ]. The morphing procedure involves the use of radial basis function interpolation using the thin-plate spline basis function and a relaxation algorithm to morph an existing FE model to a subject-specific geometry [ 31 – 33 ].…”

Section: Methodsmentioning

confidence: 99%

Development of Subject-Specific Proximal Femur Finite Element Models Of Older Adults with Obesity to Evaluate the Effects of Weight Loss on Bone Strength

et al. 2018

J Osteopor Phys Act

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Study background Recommendation of intentional weight loss in older adults remains controversial, due in part to the loss of bone mineral density (BMD) known to accompany weight loss. While finite element (FE) models have been used to assess bone strength, these methods have not been used to study the effects of weight loss. The purpose of this study is to develop subject-specific FE models of the proximal femur and study the effect of intentional weight loss on bone strength. Methods Computed tomography (CT) scans of the proximal femur of 25 overweight and obese (mean BMI=29.7 ± 4.0 kg/m2), older adults (mean age=65.6 ± 4.1 years) undergoing an 18-month intentional weight loss intervention were obtained at baseline and post-intervention. Measures of volumetric BMD (vBMD) and variable cortical thickness were derived from each subject CT scan and directly mapped to baseline and post-intervention models. Subject-specific FE models were developed using morphing techniques. Bone strength was estimated through simulation of a single-limb stance and sideways fall configuration. Results After weight loss intervention, there were significant decreases from baseline to 18 months in vBMD (total hip: −0.024 ± 0.013 g/cm3; femoral neck: −0.012 ± 0.014 g/cm3), cortical thickness (total hip: −0.044 ± 0.032 mm; femoral neck: −0.026 ± 0.039 mm), and estimated strength (stance: −0.15 ± 0.12 kN; fall: −0.04 ± 0.06 kN). Adjusting for baseline bone measures, body mass, and gender, correlations were found between weight change and change in total hip and femoral neck cortical thickness (all p<0.05). For every 1 kilogram of body mass lost cortical thickness in the total hip and femoral neck decreased by 0.003 mm and 0.004 mm, respectively. No significant correlations were present for the vBMD or strength data. Conclusion The developed subject-specific FE models could be used to better understand the effects of intentional weight loss on bone health.

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Development and Validation of an Older Occupant Finite Element Model of a Mid-Sized Male for Investigation of Age-related Injury Risk

Cited by 25 publications

References 69 publications

Effect of Exercise Modality During Weight Loss on Bone Health in Older Adults With Obesity and Cardiovascular Disease or Metabolic Syndrome: A Randomized Controlled Trial

Effect of Exercise Modality During Weight Loss on Bone Health in Older Adults With Obesity and Cardiovascular Disease or Metabolic Syndrome: A Randomized Controlled Trial

Comparing rib cortical thickness measurements from computed tomography (CT) and Micro-CT

Development of Subject-Specific Proximal Femur Finite Element Models Of Older Adults with Obesity to Evaluate the Effects of Weight Loss on Bone Strength

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