Preliminary evaluation of a new ultrasound bone densitometer.

A new ultrasound bone densitometer has been developed that measures ultrasonic properties of the os calcis, namely, the speed of sound (SOS), broadband ultrasound attenuation (BUA), and a proprietary factor derived from SOS and BUA, termed "stiffness." Short-term precision of ultrasound measurements was 1.4% for BUA, 0.2% for SOS, and 1.5% for stiffness in healthy women, and 1.1% for BUA, 0.1% for SOS, and 1.5% for stiffness in osteopenic women. One hundred seven women underwent measurements by ultrasound, together with dual energy X-ray absorptiometry (DXA) bone mineral density (BMD) measurements of the lumbar spine and proximal femur. Correlations between SOS, BUA, and stiffness measurements and DXA BMD measurements were all highly significant (P < 0.001) with r values varying from 0.54 to 0.67. BUA, SOS, and stiffness measurements were all significantly different between normal and osteopenic women even after adjusting for age, height, and weight (P < 0.05, P < 0.001, and P < 0.01, respectively). These results demonstrate that this ultrasound system measures ultrasonic properties of the os calcis with good precision, the measurements correlate moderately well with DXA BMD measurements and they can differentiate between normals and those with osteopenia.