Trabecular homogeneity index derived from plain radiograph to evaluate bone quality

Area of Science:

• Orthopedics
• Radiology
• Biomedical Engineering

Background:

• Bone quality assessment is crucial for predicting fracture risk.
• Radiographic texture analysis offers a novel approach to evaluate bone architecture.
• Trabecular bone homogeneity is a key determinant of bone strength.

Purpose of the Study:

• To validate an algorithm for calculating trabecular homogeneity index (HI) in the proximal femur from hip radiographs.
• To assess the correlation of HI with femoral strength, bone mineral density (BMD), and volumetric trabecular structure.
• To evaluate the potential of HI in identifying bones at high risk of fracture.

Main Methods:

• A semiautomatic algorithm was developed to calculate HI in the femoral neck and trochanteric areas from 178 hip radiographs.
• Corresponding CT scans were used to determine volumetric trabecular structure parameters.
• Femoral strength was measured via experimental side-impact testing, and BMD was assessed using DXA.

Main Results:

• The trabecular homogeneity index (HI) explained 50% of the experimental failure load (R² = 0.50), improving to 58% for cervical fractures.
• HI demonstrated similar accuracy to BMD in discriminating bones at high risk of fracture (AUC = 0.87).
• HI showed strong correlations with site-specific BMD (R² = 0.66 for the neck) and volumetric parameters.

Conclusions:

• The validated algorithm provides a reliable method for assessing trabecular homogeneity index (HI) from hip radiographs.
• HI is a valuable predictor of femoral strength and fracture risk, comparable to BMD.
• This radiographic texture analysis technique offers a promising, non-invasive tool for bone quality assessment.