[Bone density measurement: quantitative ultrasound of the calcaneus and distal radius. A comparison with dual spectrum X-ray absorptiometry].

BACKGROUND AND OBJECTIVE: Quantitative ultrasound (QUS) has been successfully used for more than a decade in predicting the risk of osteoporotic fractures. However, the "gold standard" in the diagnosis of osteoporosis is dual-energy X-ray absorptiometry (DXA). The aim of this study was to perform QUS at the calcaneus and distal radius, as well as DXA over the lumbar spine and proximal femur in women and to compare both QUS results with the DXA ones. PATIENTS AND METHODS: 230 postmenopausal Bulgarian women, aged between 42 and 80 years, took part in this study. QUS was performed ar the calcaneus and the radius. At the calcaneus the "quantitative ultrasound index" (QUI) was used, but at the radius the speed of sound (SOS) T-scores (SD's under the mean value for young healthy adults) were calculated. RESULTS: The highest accuracy was observed at the radius (coefficient of variance 0.59 %), followed by that for the total hip (0.95 %). The lowest mean T-scores were found at the lumbar spine (-1.94), followed by the calcaneus (-1.85) und radius (-1.74). The correlation coefficients between calcaneal QUI and BMD of the lumbar spine and proximal femur were 0,285 and 0.442 (p=0.059 and 0.001, respectively); the corresponding values for radial SOS were 0.201 and 0.061 (p=0.019 and 0.513, respectively: no significant difference). T-scores of -1.0 for the Sahara device and of -0.5 for the Sunlight device identified women without spinal osteoporosis with a 90% probability. CONCLUSIONS: Women with normal bone density of the proximal femur were better identified using transverse QUS at the calcaneus. Both QUS techniques (transverse and axial) are well suited for identifying women without osteoporosis of the lumbar spine.