Bone material ultrasound velocity is predictive of whole bone strength

In humans, bone strength is assessed indirectly by the noninvasive measurem ent of structure or mass, Recent clinical application of an ultrasonic crit ical-angle reflectometry technique (UCR) has demonstrated the measurement o f the regional and directional distribution of mechanical stiffness. This s tudy investigates the specific question: are these measurements of a local material level property predictive of the strength of whole bone? Maximum v alues of pressure wave velocity and breaking strength were recorded at two locations (midshaft and base of neck) on rat femurs from growing rats. The results demonstrate a strong empirical relationship between material-level ultrasound (US) velocity and whole bone mechanical strength. However, the U S velocity at a specific bone site can be used to assess bone strength at t hat site only, explaining discrepancies in other published studies that neg ate a relationship between strength and US velocity. The results indicate a n important role for US velocity measurement in clinical evaluation of bone health, (C) 2001 World Federation for Ultrasound in Medicine & Biology.