Estimation of in vivo cortical bone thickness using ultrasonic waves

Purpose To verify the measurement of cortical bone thickness at the distal radius in vivo using an ultrasonic method. Methods The method for estimating cortical bone thickness was derived from experiments with in vitro bovine specimens. Propagation time of echo waves and propagation time of slow waves were used for the estimation. The outside diameter of cortical bone and the cortical bone thickness at the distal 5.5 % site of radius were measured with the new ultrasonic bone measurement system, and the results were compared with X-ray pQCT clinical measurements. Results There was a high positive correlation ( r : 0.76) between the cortical bone thickness measured by the new ultrasonic system and the X-ray pQCT results. Conclusion We will be able to measure not only cancellous bone density but also cortical bone thickness in vivo using ultrasonic waves (without X-ray) safely and repeatedly.