Finite element analysis of trabecular bone microstructure using CT imaging and continuum mechanical modeling.

Area of Science:

• Biomedical Engineering
• Orthopedics
• Radiology

Background:

• Osteoporosis is characterized by bone loss and microstructural degeneration, increasing fracture risk.
• Finite element (FE) modeling estimates trabecular bone (Tb) modulus using imaging like micro-CT, MRI, and HR-pQCT.
• Accurate assessment of bone mechanical properties is crucial for managing osteoporosis.

Purpose of the Study:

• To validate voxel-based continuum finite element analysis (FEA) for predicting Tb modulus from clinical CT imaging.
• To compare FEA predictions with micro-CT and experimental measurements.
• To assess the feasibility of using FEA under in vivo-like imaging conditions.

Main Methods:

• Voxel-based continuum FEA was applied to distal tibial CT scans using linear and nonlinear models.
• CT numbers were calibrated to bone mineral density (BMD) and calcium hydroxyapatite (CHA) density.
• Mechanical properties were assigned to voxel elements based on ash-density; FEA simulated axial compressive loading.

Main Results:

• CT-derived Tb modulus showed high linear correlation with micro-CT (r=0.87-0.90) and experimental values (r=0.80-0.87).
• Linear FEA modeling demonstrated comparable correlation to nonlinear modeling.
• High reproducibility (ICC=0.98) was observed for computed modulus values.

Conclusions:

• Voxel-based continuum FEA provides surrogate measures of Tb modulus from CT imaging without Tb/marrow segmentation.
• This method accounts for bone distribution at the microstructural level.
• The approach extends FEA applications to assess bone mechanical properties from lower-resolution imaging.