Prediction of vertebral body compressive fracture using quantitative computed tomography

Area of Science:

• Orthopedic research
• Biomechanical engineering
• Medical imaging

Background:

• Accurate assessment of vertebral bone strength is crucial for fracture risk prediction.
• Quantitative computed tomography (QCT) is a non-invasive imaging technique used to assess bone mineral density.
• The relationship between QCT values, bone density, and vertebral compressive strength requires further elucidation.

Purpose of the Study:

• To evaluate the correlation between QCT measurements and apparent bone density in human lumbar vertebrae.
• To determine the relationship between apparent bone density and vertebral compressive strength.
• To assess the direct predictive capability of QCT values for vertebral compressive strength.

Main Methods:

• In vitro quantitative computed tomography (QCT) was performed on human lumbar vertebrae (L1, L3).
• Dibasic potassium phosphate phantom used for QCT calibration.
• Uniaxial compression tests to failure were conducted on vertebral bodies.
• Cortical shell integrity's effect on compressive strength was investigated.

Main Results:

• QCT numbers strongly correlated with apparent bone density (R2 = 0.89, p < 0.0001).
• Apparent bone density highly correlated with vertebral compressive strength (R2 = 0.82, p < 0.0001).
• Direct correlation between QCT values and compressive strength was suggestive but not statistically significant (R2 = 0.46, p < 0.061).

Conclusions:

• Apparent bone density is a reliable predictor of vertebral compressive strength.
• QCT values are strongly indicative of bone density but not direct predictors of vertebral strength.
• The vertebral cortical shell plays a modest role in compressive strength, with its removal causing ~10% reduction in load to failure.