Objective: Ultrasonic techniques have been used to assess the mechanical properties of bone. Recently, a new ultrasonic bone instrument, which measured the SOS (speed of sound) at the tibial shaft, has been introduced (Sound Scan 2000, Myriad Ultrasound Systems Ltd.). The aim of this work was to investigate the correlation of tibial SOS with bone mineral density (BMD).
Methods: The tibial SOS was measured in 213 healthy women (aged 22-83 years) and 56 female primary osteoporosis with vertebral fractures (aged 53-82 years). Values of SOS were compared with BMD assessed by dual energy x-ray absorptiometry (DEXA) at spine and hip sites and single photon absorptiometry (SPA) at the distal forearm.
Results: Tibial SOS correlated more closely with the BMD of lumbar, hip and forearm (r = 0.387-0.928, P < 0.001). The tibia SOS values and the BMD values measured by the DEXA and SPA were negatively correlated to age and years since menopause. In particular, they were obviously lower in the group of 50 years old. The tibial SOS of vertebral fracture group was significantly lower than that of well-matched non-fracture-group (n = 104, aged 51-84 years).
Conclusions: Tibial SOS was significantly correlated with BMD measured by DEXA or SPA respectively and able to discriminate patients with vertebral fracture from the age-matched controls.