Ultrasound attenuation imaging in the os calcis: an improved method.

A complete assessment of the broadband ultrasonic attenuation (BUA) distribution within the os calcis was made using an ultrasonic mechanical scanning device with focused transducers. Measurements were performed on 12 os calces removed from fresh female cadavers. We present the first images of BUA of the os calcis. Reasonably high quality images were obtained compared to computed tomography. The resolution provided by the focused transducers is approximately 4 or 5 mm in the focal zone. Compared to dual energy X-ray absorptiometry (DEXA) or quantitative computed tomography, ultrasound imaging of the os calcis offers the possibility of controlling the placement, size and shape of the region of interest and to use multiple measurement sites. DEXA was used systematically to measure the bone mineral density (BMD) of the os calces. A highly significant correlation between BMD and BUA was found (r = 0.97 p < 0.001).