QUANTITATIVE ULTRASOUND ASSESSMENT OF BONE IN PATIENTS WITH PRIMARY HYPERPARATHYROIDISM

Quantitative ultrasound measurements were done in a group of 26 patients (4 males and 22 females, aged 55.4 +/- 14.2 years) with primary hyperparathyroidism, and the results were compared with bone mineral density (BMD) carried out at various skeletal sites. Speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness were measured with the Achilles ultrasound bone densitometer (Lunar Corp., Madison, WI). Mean +/- SD values of SOS, BUA, and stiffness in patients with primary hyperparathyroidism were 1522 +/- 38 m/seconds, 111 +/- 16 dB/MHz, and 80.4 +/- 19.8%, respectively. There were significant differences of mean T-score BUA values (-0.63 +/- 1.11) compared with corresponding T-score BMD values found at ultradistal (-1.85 +/- 1.73, P < 0.01), proximal radius (-2.40 +/- 2.13, P < 0.001), and total femoral (-1.60 +/- 1.32, P < 0.001) sites. Correlation coefficients between both SOS and BUA values with BMD measurements at specific skeletal sites varied, but stiffness correlated moderately (0.6-0.9) with BMD. Our data strongly indicate that in patients with primary hyperparathyroidism, bone structure of some skeletal sites, as evaluated by BUA measurement, is compromised to a lesser extent than BMD. In this respect it is interesting to note the lack of significant differences (in terms of mean T-score values) in the comparison of two sites of mostly trabecular composition, that is, the lumbar level (-1.17 +/- 1.54) and the femoral Ward's triangle (-0.99 +/- 1.25). Our results seem to lend further support to the hypothesis that in primary hyperparathyroidism cancellous bone architecture might be preferentially maintained. Quantitative ultrasound techniques appear to complement, and could possibly substitute for, existing bone densitometry examinations.