Concurrent validity of the Sahara Portable Bone Sonometer

Abstract

Osteoporosis is a contemporary health issue in today’s society. Bone mineral density tests have the ability to detect low bone density before a fracture occurs. Presently dual-energy X-ray absorptiometry (DXA) is common method used to measure bone mineral density. In recent years, quantitative ultrasonography (ultrasound) has been used as a screening device at health fairs and other venues to estimate bone mineral density. The use of ultrasound offers several advantages: it exposes individuals to no radiation, it is inexpensive, and requires less tester skill and oversight than DXA. PURPOSE: To assess the accuracy of calcaneal ultrasound as a screening method compared to total body dual-energy X-ray absorptiometry. METHODS: A total of 44 men between the ages of 18-25 years (21.6 + 1.41) completed both a total body dual-energy X-ray absorptiometry (DXA) (GE Lunar) scan and an ultrasound (Hologic Sahara) calcaneus scan in a single visit. Correlation coefficients were calculated to determine the relationship between the two devices. Independent sample t-tests were used to determine if the two devices produced significantly different raw values. Bland-Altman plots were used to visually display agreement between devices. RESULTS: The ultrasound device had a weak relationship to the DXA (r = 0.514, p < 0.01). Comparing the absolute agreement between the two devices, the ultrasound device was consistently conservative. It provided mean values 0.689 g/cm2 less than the DXA. It produced values that were significantly lower (1.31 + 0.13 g/cm2 vs 0.62 + 0.14 g/cm2, p < 0.01). CONCLUSIONS: In this study, the ultrasound device produced values significantly lower than the values produced by the DXA. Ultrasound should not be used for individuals requiring high amounts of precision in their measurements. It however could be useful as a device in the screening and estimating of bone mineral density.