Ultrasound in the evaluation of osteoporosis: a comparison with bone mineral density at distal radius

It is proven that, from a technical point of view, ultrasound transmission velocity (UTV) measurement can easily be taken at the distal end of the radius. The reproducibility of UTV is good (coefficient of variation 0.3% intraoperator and 0.5% interoperator). 248 normal and 65 osteoporotic women were then studied to establish the range of UTV values and to compare the ability of UTV and bone mineral density (BMD) measurement, taken at the same skeletal sites, to detect osteoporotic fragility. Osteoporosis was defined by the presence of atraumatic vertebral fractures on an X-ray of the spine. Ultrasound velocity averaged 1570.5 +/- 43.3 m s-1 in normal and 1519.2 +/- 15.2 m s-1 in osteoporotic women; the difference is also statistically significant (p < 0.01) for BMD. Both BMD and UTV decline after menopause and are significantly correlated with age. A weak correlation (r = 0.68) was found between UTV and BMD; this supports the thesis that ultrasound velocity measures bone mass as well as other fragility components of bone distinct from the decrease of mass. Receiver operating characteristic (ROC) curve analysis showed that UTV discriminates between normal and osteoporotic patients at least as well as radial BMD, indicating that UTV is a new available diagnostic modality which can be used to screen osteoporotic subjects.