Ultrasound bone densitometry of the os calcis in the diagnosis of osteoporosis

Purpose: We evaluated the speed of sound (SOS) and broadband ultrasound attenuation (BUA) at the os calcis as an indicator of osteoporosis and observed the age-related changes in ultrasound values in normal women, Materials and methods: BUA and SOS were measured in 236 women using the ''Achilles'' densitometer (Lunar, Madison, Ohio), From the BUA and SOS values the BUA/SOS Index (''Stiffness'' Index) is calculated. We investigated 55 female patients with osteoporosis (aged 43-85 years) and 181 healthy women (aged 20-80 years). Results: Ultrasound values for women with osteoporosis were significantly lower than those for the normal control group, The Z-score compared with young normals was higher for the BUA/ SOS Index (-3.1) than for BUA (-2.5) and SOS (-3.0). At a BUA/SOS Index of 68 the sensitivity was 85%, and the specificity was 77% for patients with osteoporotic fractures. We found a significant decline with age in sos (r = -0.55), BUA (r = -0.50) and BUA/SOS Index (r = -0.57). Conclusion: Ultrasound bone densitometry at the os calcis can be used as a screening test in the diagnosis of osteoporosis.