An evaluation of the reproducibility and responsiveness of four 'state-of-the-art' ultrasonic heel bone measurement systems using phantoms

This paper evaluates four modern ultrasonic heel bone scanners: the Osteome ter DTU-one, Hologic Sahara, CUBA Clinical and Lunar Achilles+. Six phantom s, ranging in porosity from 50% to 83%, were used to evaluate the range of values of broadband ultrasonic attenuation (BUA), speed of sound (SOS) and Stiffness/quantitative ultrasound index (where available) from each machine . Differences in inter-system variability between the lowest and highest po rosity phantoms up to a factor of 3.8 were demonstrated. The reproducibilit y of each system was measured using a single phantom and gave values of 0.0 3-0.15% for SOS, 0.39-1.6% for BUA and 0.73-1.11% for Stiffness. This contr asted with values of range normalized standard deviation (CX) of 0.2-1.19% for SOS, 0.71-1.86% for BUA and 0.83-1.12% for Stiffness when the output ra nge of the measurement is taken into account. Measures of all quantities di ffered between machines and care should be taken when expressing and compar ing results from different systems.