In vivo measurement of bone quality in the horse: estimates of precision for ultrasound velocity measurement and single photon absorptiometry.

The in vivo precision of ultrasound velocity measurement and single photon absorptiometry for the assessment of equine bone quality is discussed. In vivo precisions for ultrasound velocity measurements were less than 0.5 per cent, whereas cortical cross-sectional area, compact bone density and modulus of elasticity were around 1 per cent, and bone mineral content and density were just over 2 per cent. Except for ultrasound velocity, substantial improvements could be achieved by taking the mean of five readings for each measurement. The long-term precision of the techniques was also high, with all precision values being less than 3 per cent. The possible sources of variation in ultrasound velocity measurements were also investigated. The method for combining ultrasonic and photon absorptiometric data for equine bone quality assessment has been proven to be highly accurate and precise. There appears to be no reason why the same principles cannot be applied with equal success to the noninvasive assessment of bone quality in humans.