A new material mapping procedure for quantitative computed tomography-based, continuum finite element analyses of the...

Area of Science:

• Biomechanics
• Medical Imaging
• Computational Modeling

Background:

• Quantitative computed tomography (QCT)-based finite element analysis (FEA) of vertebrae is crucial for understanding bone mechanics.
• Current methods face limitations in accuracy and precision due to material property estimation and assignment errors.
• These inaccuracies affect the reliability of FEA in predicting vertebral mechanical behavior.

Purpose of the Study:

• To develop a novel mesh-independent material mapping procedure for QCT-based FEA of vertebrae.
• To enhance the accuracy and reliability of predicting vertebral mechanical behavior.
• To improve the quality of FEA by addressing limitations in material property assignment.

Main Methods:

• Introduced a "material block model" to determine material property distribution based on bone mineral density.
• Mapped these properties onto the finite element mesh independently of element size.
• Conducted sensitivity analyses using calibration phantoms and FE analyses on vertebral models (columns and entire vertebrae).

Main Results:

• Varying material block size showed only marginal changes in bone mineral density predictions.
• Predicted vertebral stiffness decreased with decreasing material block size.
• The influence of material block size on stiffness was greater than that of finite element size.

Conclusions:

• The developed mesh-independent material mapping procedure improves QCT-based FEA of vertebrae.
• This method allows independent selection of material block size for accurate material field representation and finite element size for numerical accuracy.
• The procedure is applicable beyond vertebrae, offering potential improvements for analyses like vertebroplasty and spine metastases.