Estimating the density of femoral head trabecular bone from hip fracture patients using computed tomography scan data.

The purpose of this study was to compare computed tomography density (ρ ) obtained using typical clinical computed tomography scan parameters to ash density (ρ ), for the prediction of densities of femoral head trabecular bone from hip fracture patients. An experimental study was conducted to investigate the relationships between ρ and ρ and between each of these densities and ρ and ρ . Seven human femoral heads from hip fracture patients were computed tomography-scanned ex vivo, and 76 cylindrical trabecular bone specimens were collected. Computed tomography density was computed from computed tomography images by using a calibration Hounsfield units-based equation, whereas ρ, ρ and ρ were determined experimentally. A large variation was found in the mean Hounsfield units of the bone cores (HU) with a constant bias from ρ to ρ of 42.5 mg/cm. Computed tomography and ash densities were linearly correlated (R = 0.55, p < 0.001). It was demonstrated that ρ provided a good estimate of ρ (R = 0.78, p < 0.001) and is a strong predictor of ρ (R = 0.99, p < 0.001). In addition, the ρ was linearly related to ρ (R = 0.43, p < 0.001) and ρ (R = 0.56, p < 0.001). In conclusion, mineral density was an appropriate predictor of ρ and ρ , and ρ was not a surrogate for ρ . There were linear relationships between ρ and physical densities; however, following the experimental protocols of this study to determine ρ , considerable scatter was present in the ρ relationships.