Ultrasound velocity and attenuation at different skeletal sites compared with bone mineral density measured using dual energy X-ray absorptiometry

Measurements of ultrasound velocity were performed in the tibia in a group of 89 female subjects (mean age 50.6 years). Velocity and broadband ultrasound attenuation (BUA) measurements were performed in the os-calcis in a group of 100 male and female subjects (mean age 55.8 years). Dual energy X-ray absorptiometry (DEXA) scans were also performed on all of these subjects enabling measurements of lumbar spine and femoral neck bone mineral density (BMD) to be obtained. In two small subgroups of the above groups, each comprising 20 subjects, measurements of tibial BMD and os-calcis BMD were also performed. Tibial BMD and ultrasound velocity were found to be well correlated (r = 0.71), although both spine and femoral neck BMD were poorly correlated with ultrasound velocity in the tibia (r = 0.299 and 0.072, respectively). BUA of the os-calcis was moderately correlated with BMD al the same site (r = 0.44) and showed similar or slightly better correlations with BMD measurements of the lumbar spine and femoral neck (r = 0.410 and 0.537, respectively). Ultrasound velocity in the os-calcis was well correlated with os-calcis BMD (r = 0.729) but only moderately correlated with spine and femoral neck BMD (r = 0.470 and 0.498, respectively). This study suggests that BUA and ultrasound velocity measurements of the os-calcis are better predictors of BMD at the critical skeletal sites of the lumbar spine and femoral neck than ultrasound velocity in the tibia. Ultrasound velocity in the tibia and the os-calcis was found to be a good predictor of the BMD in the measured bone.