Comparison of broadband ultrasonic attenuation of the os calcis and quantitative computed tomography of the distal radius.

The measurement of broadband ultrasonic attenuation (BUA) in the os calcis, which consists of predominantly trabecular bone, has been compared by others with single photon absorptiometry of forearm cortical bone. We have compared BUA in 24 female subjects with the separate measurement of trabecular and cortical bone in the distal radius using quantitative computed tomography (QCT). BUA was highly significantly correlated with each of the measurements in the radius (P less than 0.001). Paradoxically, BUA was found to be best correlated with the bone mass per unit length in the radial shaft (r = 0.85) rather than with radial trabecular bone (r = 0.66). The degree of correlation was not sufficient to predict radial bone mass accurately in individuals. Broadband ultrasonic attenuation, however, appears to be a useful measurement of bone in the appendicular skeleton.