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Jan Wolff

On the limits of finite element models created from (micro)CT datasets and used in studies of bone-implant-related biomechanical problems

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  • Petr Marcián, Brno University of Technology
  • ,
  • Libor Borák, Brno University of Technology
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  • Tomáš Zikmund, Brno University of Technology
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  • Ladislava Horáčková, Masaryk University
  • ,
  • Jozef Kaiser, Brno University of Technology
  • ,
  • Marek Joukal, Masaryk University
  • ,
  • Jan Wolff

Patient-specific approach is gaining a wide popularity in computational simulations of biomechanical systems. Simulations (most often based on the finite element method) are to date routinely created using data from imaging devices such as computed tomography which makes the models seemingly very complex and sophisticated. However, using a computed tomography in finite element calculations does not necessarily enhance the quality or even credibility of the models as these depend on the quality of the input images. Low-resolution (medical-)CT datasets do not always offer detailed representation of trabecular bone in FE models and thus might lead to incorrect calculation of mechanical response to external loading. The effect of image resolution on mechanical simulations of bone-implant interaction has not been thoroughly studied yet. In this study, the effect of image resolution on the modeling procedure and resulting mechanical strains in bone was analyzed on the example of cranial implant. For this purpose, several finite element models of bone interacting with fixation-screws were generated using seven computed tomography datasets of a bone specimen but with different image resolutions (ranging from micro-CT resolution of 25 μm to medical-CT resolution of 1250 μm). The comparative analysis revealed that FE models created from images of low resolution (obtained from medical computed tomography) can produce biased results. There are two main reasons: 1. Medical computed tomography images do not allow generating models with complex trabecular architecture which leads to substituting of the intertrabecular pores with a fictitious mass; 2. Image gray value distribution can be distorted resulting in incorrect mechanical properties of the bone and thus in unrealistic or even completely fictitious mechanical strains. The biased results of calculated mechanical strains can lead to incorrect conclusion, especially when bone-implant interaction is investigated. The image resolution was observed not to significantly affect stresses in the fixation screw itself; however, selection of bone material representation might result in significantly different stresses in the screw.

Original languageEnglish
Article number104393
JournalJournal of the Mechanical Behavior of Biomedical Materials
Number of pages13
Publication statusPublished - May 2021
Externally publishedYes

Bibliographical note

Copyright © 2021 Elsevier Ltd. All rights reserved.

    Research areas

  • Biomechanical Phenomena, Bone Screws, Bone and Bones, Finite Element Analysis, Humans, Stress, Mechanical, X-Ray Microtomography

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