Evaluation of dual energy x-ray absorptiometry for in situ measurement of bone mineral density of equine metacarpi.

The study aims to validate the efficiency of dual energy x-ray absorptiometry (DEXA) in accurately and precisely measuring the bone mineral density of horses’ forelimbs, specifically the metacarpus, in situ.

Methodology

• The study used 12 forelimbs from 12 randomly selected horses.
• The metacarpi, which is the bone in the forelimbs of horses, were scanned in two different planes and DEXA measurements were taken for six separate regions of interest (ROI).
• The researchers isolated each of these ROI and measured the bone density using Archimedes’ principle, an established method in the physical sciences used to determine density.
• Linear regression analysis, a statistical technique that studies the relationship between two variables, was employed to find the correlation between the two measurements for each ROI.
• To ascertain the coefficient of variation, or the relative variability of the measurement method, an extra metacarpus was measured ten times using both techniques.

Results

• The associations between the DEXA measurements and the bone densities were found to be significantly high in multiple regions of interest.
• These associations improved with the addition of variables such as age, weight, and the thickness of the soft tissue or bone.
• Repeated measurements indicated a low coefficient of variation, suggesting a high level of precision and reproducibility in the DEXA technique.

Conclusions

• The results demonstrate that DEXA can accurately and precisely measure the bone density of the equine metacarpus.
• The study also suggests that DEXA can be successfully used for ongoing in vivo measurements of bone density in the equine metacarpus — that is, measurements conducted on the living horse as opposed to a removed limb.
• The researchers propose that DEXA could be effectively employed in future studies to evaluate how diet or drugs may affect bone density, or to track changes in bone density due to bone remodeling before stress fractures occur.