Low-frequency axial ultrasound velocity correlates with bone mineral density and cortical thickness in the radius and tibia in pre- and postmenopausal women

Summary Axial transmission velocity of a low-frequency first arriving signal ( V LF ) was assessed in the radius and tibia of 254 females, and compared to site-matched pQCT measurements. V LF best correlated with cortical BMD, but significantly also with subcortical BMD and cortical thickness. Correlations were strongest for the radius in postmenopausal females. Introduction Ultrasonic low-frequency (LF; 0.2–0.4 MHz) axial transmission, based on the first arriving signal (FAS), provides enhanced sensitivity to thickness and endosteal properties of cortical wall of the radius and tibia compared to using higher frequencies (e.g., 1 MHz). This improved sensitivity of the LF approach has not yet been clearly confirmed by an in vivo study on adult subjects. The aims of the present study were to evaluate the extent to which LF measurements reflect cortical thickness and bone mineral density, and to assess whether an individual LF measurement can provide a useful estimate for these bone properties. Methods Velocity of the LF FAS ( V LF ) was assessed in the radius and tibia shaft by a new ultrasonometer (CV RMS = 0.5%) in a cross-sectional study involving 159 premenopausal (20–58 years) and 95 postmenopausal females (45–88 years). Site-matched volumetric total bone mineral density (BMD), cortical bone mineral density (CBMD), subcortical bone mineral density (ScBMD) and cortical thickness (CTh) were assessed using pQCT. Results For the postmenopausal females, V LF correlated best with CBMD in the radius ( R = 0.850, p