Optimizing DXA to assess skeletal health: Key concepts for clinicians

Context: The diagnosis of osteoporosis and assessment of fracture risk prior to a sentinel fracture was transformed by the widespread clinical use of dual-energy X-ray absorptiometry (DXA) for the assessment of bone mineral density (BMD). Evidence Acquisition: This review is based on a collection of primary and review literature gathered from a PubMed search of “dual energy X-ray absorptiometry,” “trabecular bone score,” and “atypical femur fracture” among other keywords. PubMed searches were supplemented by the authors’ prior knowledge of the subject. Evidence Synthesis: While uncertainty exists for some aspects of osteoporosis care, patient and clinician familiarity with BMD assessment for screening and monitoring is firmly established. Beyond BMD, lateral spine images obtained with DXA can diagnose osteoporosis and refine fracture risk through the detection of unrecognized vertebral fractures. In addition, analysis of DXA lumbar spine images can reflect changes in trabecular bone microarchitecture, a component of bone “quality” that predicts risk of fracture independent of BMD. Finally, monitoring of bone health by DXA may be extended to include assessment of the femoral cortices for rare but serious adverse effects associated with antiresorptive therapies. Conclusions: Increasing technologic sophistication requires additional consideration for how DXA imaging is performed, interpreted and applied to patient care. As with any test, clinicians must be familiar with DXA performance, pitfalls in analysis, and interpretation within each clinical context in which DXA is applied. With this perspective, care providers will be well positioned to contribute to continuous improvement of DXA performance and, in turn, quality of osteoporosis care.