In vivo ultrasonic evaluation of distal part of radius in their early teens

For the evaluation of small radius of early teens, we have improved the ultrasonic bone measurement system, LD-100 (OYO electric)¹, which can evaluate the distal 5.5 % site of the radius of the non-dominant hand. The system measures two longitudinal waves (fast and slow waves) which propagate in the inside cancellous bone. We can also obtain the spatial distribution of wave attenuation during propagation in bone, which can be presented as an attenuation map. In our present teen’s bone evaluation project (ages 12-18, n = 971), we found an open epiphysis at the distal end of radius in some attenuation maps of early teens. The area seems to be the growth plate, which have the ability to lengthen the bone by creating new cartilage within the bone itself. In case of boys, the plates were found at the age of 14 or less. The values of body weights and heights of the teens with the growth plates were smaller than the average, telling that they are growing up. These results show the possibility of growth evaluation using ultrasound techniques. 1. H. Sai, et al., Osteoporos Int. (2010) 21:1781–1790.