Pulse-echo ultrasonometry can be used as a pre-screen for hip osteoporosis before dual-energy x-ray absorptiometry (DXA), potentially allowing DXA to be avoided for the majority of post-menopausal women. Pulse-echo ultrasound measures of tibia cortical thickness are also associated with radiographically confirmed prior fractures, independent of femoral neck bone mineral density.
Introduction: To estimate how well a pulse-echo ultrasound device discriminates those who have from those who do not have hip osteoporosis (femoral neck bone mineral density [BMD] or total hip BMD T-score ≤ -2.5), and to estimate the association of pulse-echo ultrasound measures with prevalent (radiographically confirmed) clinical fractures.
Methods: Five hundred fifty-five post-menopausal women age 50 to 89 had femoral neck and total hip BMD measured by dual-energy x-ray absorptiometry (DXA), and pulse-echo ultrasound measures of distal radius, proximal tibia, distal tibia cortical thickness, and multi- and single-site density indices (DI). Using previously published threshold ultrasound values, we estimated the proportion of women who would avoid a follow-up DXA after pulse-echo ultrasonometry, and the sensitivity and specificity of this for the detection of hip osteoporosis. Logistic regression models were used to estimate the associations of pulse-echo ultrasound measures with radiographically confirmed clinical fractures within the prior 5 years.
Results: Using multi-site and single-site DI measures, follow-up DXA could be avoided for 73 and 69 % of individuals, respectively, while detecting hip osteoporosis with 80-82 % sensitivity and 81 % specificity. Radiographically confirmed prior fracture was associated with ultrasound measures of single-site DI (odds ratio (OR) 1.55, 95 % confidence interval (CI). 1.06 to 2.26) and proximal tibia cortical thickness (OR 1.47, 95 % CI 1.10 to 1.96), adjusted for age, body mass index, and femoral neck BMD.
Conclusions: Pulse-echo ultrasonometry can be used as an initial screening test for hip osteoporosis. Prospective studies of how well pulse-echo ultrasound measures predict subsequent clinical fractures are warranted.
Keywords: Bone mineral density; Cortical thickness; Osteoporosis; Pulse-echo ultrasound; Quantitative ultrasound.