Dual X-ray and laser absorptiometry of the calcaneus: comparison with quantitative ultrasound and dual-energy X-ray absorptiometry

The aim of our study was to evaluate the reproducibility and the diagnostic accuracy of a new device for the assessment of bone mineral density (BMD) of the heel, called dual X-ray and laser (DXL Calscan). This technique associates X-ray absorptiometry to the measure of heel thickness with a laser beam. The calcaneus BMD, calcaneus quantitative sonography (QUS), and lumbar spine and total-body BMD, were evaluated in 40 postmenopausal women. On the basis of the BMD T-score measured by dual-energy X-ray absorptiometry (DXA) of L2-L4, 20 women were classified as osteoporotic and 20 women were considered nonosteoporotic according to the WHO classification. The short-term coefficient of variation of the DXL was 2.4% and 1.7% in osteoporotic and nonosteoporotic women, respectively. The calcaneus BMD was lower in osteoporotic than in nonosteoporotic women. Among osteoporotic patients, 14 patients had a T-score lower than -2.5 at Calscan, whereas only 4 patients classified as nonosteoporotic based on the lumbar spine BMD were misclassified by Calscan. In these patients, the sensitivity and specificity of heel ultrasound measurements were 70% and 85%, respectively. The DXL BMD was highly correlated with the total-body BMD, Stiffness at the calcaneus, and the L2-L4 BMD. In conclusion, the new measuring device the Calscan DXL appeared easy to use, the time of examination was relatively short, and the reproducibility was sufficiently good; the diagnostic accuracy and relationships with other devices were good.