July - September 2008, Volume 4, Issue 3

Georgescu C, Ilie I, Paul A, Mihu D, Duncea I, Mocanu T, Duncea I

Value of quantitative heel and proximal phalanges ultrasonography versus dual X-ray absorptiometry in women aged 24-80 years

Acta Endo (Buc) 2008, 4 (3): 297-308
doi: 10.4183/aeb.2008.297

Despite several attempts to establish the role of QUS in clinical practice, issues such as definition of osteoporosis based on QUS, screening strategy and therapy efficacy for patients identified by QUS as having high risk of fracture remain a matter of debate. The present study aimed to evaluate the diagnostic agreement between two QUS techniques (heel QUS and proximal phalanges QUS) and DXA in an unselected population of Romanian women aged 24- 80 years, as well as to offer cut-off levels for QUS to distinct between women with or without osteoporosis identified by DXA. In women measured by both DXA and calcaneus QUS (c- QUS), bone mineral density (BMD) moderately correlated with stiffness index (SI) (L1-L4: r=+0.51, p<0.001; femoral neck: r=+0.53, p<0.001; hip: r=+0.57, p<0.001), while in women examined by both DXA and phalanx QUS (ph-QUS), BMD was positively related to amplitude-dependent speed of sound (Ad-SoS) (L1-L4: r=+0.47, p<0.001; femoral neck: r=+0.50, p<0.001; hip: r=+0.38, p<0.001) and ultrasound bone profile index (UBPI) (L1-L4: r=+0.44, p<0.001; femoral neck: r=+0.50, p<0.001; hip: r=+0.38, p<0.001). At a T-score cutoff level of -2.5SD, the high specificity but low sensitivity suggests a low false positive rate of c-QUS as a diagnostic test; still, several patients with the disease may not be correctly diagnosed. At the same cut-off level, ph-QUS showed higher sensitivity and lower specificity. Diagnostic agreement between DXA and QUS was poor, with k-scores ranging from 0.33 to 0.39 for c-QUS and from 0.14 to 0.29 for ph-QUS, respectively. Lowering c-QUS T-score cutoff for lumbar spine osteoporosis screening to -1.5SD and ph-QUS T-score cut-off to -1.9SD, respectively, improved sensitivity and had a minor effect on diagnostic agreement. Regardless of the evaluated site, neither c-QUS nor ph-QUS does represent an adequate predictor of BMD in Romanian women. Changing the diagnostic T-score threshold from -2.5 SD to -1.5 SD and -1.9 SD in subjects examined by c-QUS or ph-QUS, respectively, is followed by improved sensitivity and diagnostic agreement in the identification of patients with vertebral osteoporosis. Cut-off values may allow QUS to be used as a screening tool for spine and femur osteoporosis.

Keywords: dual X-ray absorptiometry, quantitative phalanges ultrasonography, quantitative heel ultrasonography, osteoporosis, fracture

Correspondence: Carmen Georgescu, MD, Clinics of Endocrinology, 3 Louis Pasteur 400349 Cluj-Napoca, Romania Tel: +40 64 595236, Fax: +40 64 429358, E-mail: c_e_georgescu@yahoo.com