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Assessment of the 3-D shape and mechanics of the proximal femur using a shape template and a bone mineral density image

Väänänen, Sami; Isaksson, Hanna LU ; Julkunen, Petro; Sirola, Joonas; Kröger, Heikki and Jurvelin, Jukka (2011) In Biomechanics and Modeling in Mechanobiology 10(4). p.529-538
Abstract
Measurement of bone mineral density (BMD) by DXA (dual-energy X-ray absorptiometry) is generally considered to be the clinical golden standard technique to diagnose osteoporosis. However, BMD alone is only a moderate predictor of fracture risk. Finite element analyses of bone mechanics can contribute to a more accurate prediction of fracture risk. In this study, we applied a method to estimate the 3D geometrical shape of bone based on a 2D BMD image and a femur shape template. Proximal femurs of eighteen human cadavers were imaged with computed tomography (CT) and divided into two groups. Image data from the first group (N = 9) were applied to create a shape template by using the general Procrustes analysis and thin plate splines. This... (More)
Measurement of bone mineral density (BMD) by DXA (dual-energy X-ray absorptiometry) is generally considered to be the clinical golden standard technique to diagnose osteoporosis. However, BMD alone is only a moderate predictor of fracture risk. Finite element analyses of bone mechanics can contribute to a more accurate prediction of fracture risk. In this study, we applied a method to estimate the 3D geometrical shape of bone based on a 2D BMD image and a femur shape template. Proximal femurs of eighteen human cadavers were imaged with computed tomography (CT) and divided into two groups. Image data from the first group (N = 9) were applied to create a shape template by using the general Procrustes analysis and thin plate splines. This template was then applied to estimate the shape of the femurs in the second group (N = 9), using the 2D BMD image projected from the CT image, and the geometrical errors of the shape estimation method were evaluated. Finally, finite element analysis with stance loading condition was conducted based on the original CT and the estimated geometrical shape to evaluate the effect of the geometrical errors on the outcome of the simulations. The volumetric errors induced by the shape estimation method itself were low (<0.6%). Increasing the number of bone specimens used for the template decreased the geometrical errors. When nine bones were used for the template, the mean distance difference (±SD) between the estimated and the CT shape surfaces was 1.2 ± 0.3 mm, indicating that the method was feasible for estimating the shape of the proximal femur. Small errors in geometry led systematically to larger errors in the mechanical simulations. The method could provide more information of the mechanical characteristics of bone based on 2D BMD radiography and could ultimately lead to more sensitive diagnosis of osteoporosis. (Less)
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author
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type
Contribution to journal
publication status
published
subject
in
Biomechanics and Modeling in Mechanobiology
volume
10
issue
4
pages
529 - 538
publisher
Springer
external identifiers
  • scopus:80054070019
ISSN
1617-7940
DOI
10.1007/s10237-010-0253-3
language
English
LU publication?
no
id
01a0d240-4ffc-4097-b7a7-bd5cc36e6d46 (old id 2277198)
date added to LUP
2012-01-27 09:37:22
date last changed
2017-01-01 04:04:52
@article{01a0d240-4ffc-4097-b7a7-bd5cc36e6d46,
  abstract     = {Measurement of bone mineral density (BMD) by DXA (dual-energy X-ray absorptiometry) is generally considered to be the clinical golden standard technique to diagnose osteoporosis. However, BMD alone is only a moderate predictor of fracture risk. Finite element analyses of bone mechanics can contribute to a more accurate prediction of fracture risk. In this study, we applied a method to estimate the 3D geometrical shape of bone based on a 2D BMD image and a femur shape template. Proximal femurs of eighteen human cadavers were imaged with computed tomography (CT) and divided into two groups. Image data from the first group (N = 9) were applied to create a shape template by using the general Procrustes analysis and thin plate splines. This template was then applied to estimate the shape of the femurs in the second group (N = 9), using the 2D BMD image projected from the CT image, and the geometrical errors of the shape estimation method were evaluated. Finally, finite element analysis with stance loading condition was conducted based on the original CT and the estimated geometrical shape to evaluate the effect of the geometrical errors on the outcome of the simulations. The volumetric errors induced by the shape estimation method itself were low (&lt;0.6%). Increasing the number of bone specimens used for the template decreased the geometrical errors. When nine bones were used for the template, the mean distance difference (±SD) between the estimated and the CT shape surfaces was 1.2 ± 0.3 mm, indicating that the method was feasible for estimating the shape of the proximal femur. Small errors in geometry led systematically to larger errors in the mechanical simulations. The method could provide more information of the mechanical characteristics of bone based on 2D BMD radiography and could ultimately lead to more sensitive diagnosis of osteoporosis.},
  author       = {Väänänen, Sami and Isaksson, Hanna and Julkunen, Petro and Sirola, Joonas and Kröger, Heikki and Jurvelin, Jukka},
  issn         = {1617-7940},
  language     = {eng},
  number       = {4},
  pages        = {529--538},
  publisher    = {Springer},
  series       = {Biomechanics and Modeling in Mechanobiology},
  title        = {Assessment of the 3-D shape and mechanics of the proximal femur using a shape template and a bone mineral density image},
  url          = {http://dx.doi.org/10.1007/s10237-010-0253-3},
  volume       = {10},
  year         = {2011},
}