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Validation of 3d finite element models from simulated Dxa images for Biofidelic simulations of sideways fall impact to the hip

Grassi, Lorenzo LU ; Fleps, Ingmar ; Sahlstedt, Hannicka LU ; Väänänen, Sami P ; Ferguson, Stephen J ; Isaksson, Hanna LU and Helgason, Benedikt (2020) In Bone
Abstract

Computed tomography (CT)-derived finite element (FE) models have been proposed as a tool to improve the current clinical assessment of osteoporosis and personalized hip fracture risk by providing an accurate estimate of femoral strength. However, this solution has two main drawbacks, namely: (i) 3D CT images are needed, whereas 2D dual-energy x-ray absorptiometry (DXA) images are more generally available, and (ii) quasi-static femoral strength is predicted as a surrogate for fracture risk, instead of predicting whether a fall would result in a fracture or not. The aim of this study was to combine a biofidelic fall simulation technique, based on 3D computed tomography (CT) data with an algorithm that reconstructs 3D femoral shape and BMD... (More)

Computed tomography (CT)-derived finite element (FE) models have been proposed as a tool to improve the current clinical assessment of osteoporosis and personalized hip fracture risk by providing an accurate estimate of femoral strength. However, this solution has two main drawbacks, namely: (i) 3D CT images are needed, whereas 2D dual-energy x-ray absorptiometry (DXA) images are more generally available, and (ii) quasi-static femoral strength is predicted as a surrogate for fracture risk, instead of predicting whether a fall would result in a fracture or not. The aim of this study was to combine a biofidelic fall simulation technique, based on 3D computed tomography (CT) data with an algorithm that reconstructs 3D femoral shape and BMD distribution from a 2D DXA image. This approach was evaluated on 11 pelvis-femur constructs for which CT scans, ex vivo sideways fall impact experiments and CT-derived biofidelic FE models were available. Simulated DXA images were used to reconstruct the 3D shape and bone mineral density (BMD) distribution of the left femurs by registering a projection of a statistical shape and appearance model with a genetic optimization algorithm. The 2D-to-3D reconstructed femurs were meshed, and the resulting FE models inserted into a biofidelic FE modeling pipeline for simulating a sideways fall. The median 2D-to-3D reconstruction error was 1.02 mm for the shape and 0.06 g/cm3 for BMD for the 11 specimens. FE models derived from simulated DXAs predicted the outcome of the falls in terms of fracture versus non-fracture with the same accuracy as the CT-derived FE models. This study represents a milestone towards improved assessment of hip fracture risk based on widely available clinical DXA images.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Fracture risk assessment, Biomechanics, Statistical shape model, Validation, Statistical appearance models, Orthopedics
in
Bone
article number
115678
publisher
Elsevier
external identifiers
  • pmid:33022451
ISSN
1873-2763
DOI
10.1016/j.bone.2020.115678
language
English
LU publication?
yes
additional info
Copyright © 2020. Published by Elsevier Inc.
id
7d694d6b-712f-47b0-828a-7c62ba7f7f83
date added to LUP
2020-10-15 08:09:33
date last changed
2020-10-15 15:50:17
@article{7d694d6b-712f-47b0-828a-7c62ba7f7f83,
  abstract     = {<p>Computed tomography (CT)-derived finite element (FE) models have been proposed as a tool to improve the current clinical assessment of osteoporosis and personalized hip fracture risk by providing an accurate estimate of femoral strength. However, this solution has two main drawbacks, namely: (i) 3D CT images are needed, whereas 2D dual-energy x-ray absorptiometry (DXA) images are more generally available, and (ii) quasi-static femoral strength is predicted as a surrogate for fracture risk, instead of predicting whether a fall would result in a fracture or not. The aim of this study was to combine a biofidelic fall simulation technique, based on 3D computed tomography (CT) data with an algorithm that reconstructs 3D femoral shape and BMD distribution from a 2D DXA image. This approach was evaluated on 11 pelvis-femur constructs for which CT scans, ex vivo sideways fall impact experiments and CT-derived biofidelic FE models were available. Simulated DXA images were used to reconstruct the 3D shape and bone mineral density (BMD) distribution of the left femurs by registering a projection of a statistical shape and appearance model with a genetic optimization algorithm. The 2D-to-3D reconstructed femurs were meshed, and the resulting FE models inserted into a biofidelic FE modeling pipeline for simulating a sideways fall. The median 2D-to-3D reconstruction error was 1.02 mm for the shape and 0.06 g/cm3 for BMD for the 11 specimens. FE models derived from simulated DXAs predicted the outcome of the falls in terms of fracture versus non-fracture with the same accuracy as the CT-derived FE models. This study represents a milestone towards improved assessment of hip fracture risk based on widely available clinical DXA images.</p>},
  author       = {Grassi, Lorenzo and Fleps, Ingmar and Sahlstedt, Hannicka and Väänänen, Sami P and Ferguson, Stephen J and Isaksson, Hanna and Helgason, Benedikt},
  issn         = {1873-2763},
  language     = {eng},
  month        = {10},
  publisher    = {Elsevier},
  series       = {Bone},
  title        = {Validation of 3d finite element models from simulated Dxa images for Biofidelic simulations of sideways fall impact to the hip},
  url          = {http://dx.doi.org/10.1016/j.bone.2020.115678},
  doi          = {10.1016/j.bone.2020.115678},
  year         = {2020},
}