Calcaneal quantitative ultrasound compared with hip and femoral neck dual-energy x-ray absorptiometry in people with a spinal cord injury

Objective: To evaluate the sensitivity and specificity of calcaneal quantitative ultrasound (QUS) measurements for identifying osteoporosis determined by dual-energy x-ray absorptiometry (DXA) at the hip in a spinal cord injury (SCI) population. Design: Cross-sectional retrospective review of data collected in the bone health registry of persons with a disability. Setting: Inpatients and outpatients at a single acute rehabilitation hospital. Participants: A convenience sample of 66 participants, both inpatients and outpatients, with a spinal cord injury. Methods: Calcaneal T scores were determined by ultrasound, and bone density of the lumbar spine, total hip, and femoral neck were determined by DXA. Main Outcome Measurements: Right and left calcaneal QUS T scores and right and left hip and femoral neck DXA T scores. Results: Right and left hip DXA T scores were strongly associated with corresponding right and left calcaneal QUS T scores (right: r = .72, P < .001; left: r = .70, P < .001). Similar associations were found when we evaluated femoral neck T scores and calcaneal QUS T scores. Receiver operating characteristic analysis for evaluating QUS to identify DXA-defined osteoporosis demonstrated an area under the curve of 0.81 for all participants (acute and chronic injury) and 0.68 for those with a chronic SCI. Conclusions: A strong association exists between calcaneal QUS T scores and bone density T scores at the hip measured by DXA. QUS may have a place in the screening of people with SCI 1 year or more after their injury to evaluate their bone status.