Hip fracture discrimination by the Achilles Insight QUS imaging device

The importance of osteoporosis as a major health problem is well recognized. Its major clinical manifestation is low energy fractures. Considerable effort has been directed towards search of noninvasive methods for assessing osteoporotic fracture risk. The aim of this study was to evaluate the ability of quantitative ultrasound (QUS) variables measured by a new heel QUS imaging device to discriminate between postmenopausal women with and without hip fracture. The subjects included 30 postmenopausal female patients with hip fracture and 30 age-matched healthy women. Measurements were acquired using the Achilles Insight QUS imaging device. Bone mineral density (BMD) measurements were carried out using the Lunar Prodigy DXA scanner. Achilles Insight provides images of the heel bone and measures broadband ultrasound attenuation (BUA) and speed of sound (SOS) values in a circular region of interest. A third QUS variable, the stiffness index (SI) was also determined. The short-term precision for healthy subjects was 2.05%, 0.17% and 1.91% for BUA, SOS and SI, respectively. Corresponding values for patients with fractures were 1.80%, 0.16% and 2.04%. All QUS variables measured using the Achilles Insight were significant discriminators of hip fractures (area under ROC curve=0.77, 0.74 and 0.77 for BUA, SOS and SI, respectively). BMD measurements of the hip had the greatest discriminatory ability (area under ROC curve=0.88). Statistically significant differences were found between the area under the ROC curve of BMD and the corresponding curves of the QUS variables (P<0.05 for each of the three comparisons). QUS variables measured by Achilles Insight can be expected to be useful as indicators of the risk of hip fracture in postmenopausal women.