Cf. Njeh et al., Comparison of six calcaneal quantitative ultrasound devices: Precision andhip fracture discrimination, OSTEOPOR IN, 11(12), 2000, pp. 1051-1062
Quantitative ultrasound (QUS) is now accepted as a useful tool in the manag
ement of osteoporosis. There are a variety of QUS devices clinically availa
ble with a number of differences among them, including their coupling metho
ds, parameter calculation algorithms and sites of measurement. This study e
valuated the abilities of six calcaneal QUS devices to discriminate between
normal and hip-fractured subjects compared with the established method of
dual-energy X-ray absorptiometry (DXA). The short-term and mid-term precisi
ons of these devices were also determined. Thirty-five women (mean age 74.5
+/- 7.9 years) who had sustained a hip fracture within the past 3 years, a
nd 35 age-matched controls (75.8 +/- 5.6 years) were recruited. Ultrasound
measurements were acquired using six ultrasound devices: three gel-coupled
and three water-coupled devices. Bone mineral density was measured at the h
ip using DXA. Discrimination of fracture patients versus controls was asses
sed using logistic regression analysis (expressed as age- and BMI-adjusted
odds ratios per standard deviation decrease with 95% confidence interval) a
nd receiver operating characteristics (ROC) curve analysis. Measurement pre
cision was standardized to the biological range (sCV). The sCV ranged from
3.14% to 5.5% for speed of sound (SOS) and from 2.45% to 6.01% for broadban
d ultrasound attenuation (BUA). The standardized medium-term precision rang
ed from 4.33% to 8.43% for SOS and from 2.77% to 6.91% for BUA. The pairwis
e Pearson correlation coefficients between different devices was highly sig
nificant (SOS, r = 0.79-0.93; BUA, r = 0.71-0.92). QUS variables correlated
weakly, though significantly, with femoral BMD (SOS, r = 0.30-0.55; BUA, r
= 0.35-0.61). The absolute BUA and SOS values varied among devices. The ge
l-coupled devices generally had a higher SOS than water-coupled devices. Bo
ne mineral density (BMD) and BUA were weakly correlated with weight (r = 0.
48-0.57 for BMD and r = 0.18-0.54 for BUA), whereas SOS was independent of
weight. All the QUS devices gave similar, statistically significant hip fra
cture discrimination for both SOS and BUA measures. The odds ratios for SOS
(2.1-2.8) and BUA (2.4-3.4) were comparable to those for femoral BMD (2.6-
3.5), as were the area under the curve (SOS, 0.65-0.71; BUA, 0.62-0.71; BMD
, 0.65-0.74) from ROC analysis. Within the limitation of the sample size ai
l devices show similar diagnostic sensitivity.