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

Abstract

Objective - To determine the accuracy and precision of dual energy x-ray absorptiometry (DEXA) for measuring bone mineral density in horses in situ. Sample Population - 12 randomly selected forelimbs from 12 horses. Procedure - Metacarpi were scanned in 2 planes and DEXA measurements obtained for 6 regions of interest (ROI). Each ROI was isolated and bone density measured by Archimedes' principle. Linear regression analysis was used to determine the correlation between the 2 measurements at each ROI. An additional metacarpus was measured 10 times to determine the coefficient of variation for both techniques. Results - Dual energy x-ray absorptiometry and bone density were significantly associated at multiple ROI. The addition of age, weight, and soft tissue or bone thickness improved these associations. Repeated measurements had a low coefficient of variation. Conclusions and Clinical Relevance - Dual energy x-ray absorptiometry can be used to accurately and precisely measure the bone density in the equine metacarpus. Dual energy x-ray absorptiometry appears suitable for serial in vivo measurement of bone density of the equine metacarpus. Dual energy x-ray absorptiometry may be used for studies to evaluate the effects of diet or drugs on bone density or density changes from bone remodeling that develop prior to stress fractures.