Bone Density Measurement

Bone degeneration, i.e., osteoporosis, remains a major public health problem through its association with fragility fractures. Bone mineral density (BMD) measurement is a clinical tool to diagnose osteoporosis or low bone density, predict the risk of fracture, and monitor changes in bone density over time. Assessment of BMD has become as essential element in the early evaluation of patients at risk for osteopenia and osteoporosis. The noninvasive measurement of BMD is done with a variety of technologies for many different skeletal sites. Many image modalities and techniques have been developed to improve the quality and the accuracy of the measurement for bone mineral and dense assessment. There are two major densitometry techniques commonly used in assessing bone density, i.e., radiography-based densitometry and ultrasound-based assessment. Dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) are two current acceptable modalities for bone density testing and the assessment tools for predicting fracture risk. Growing awareness of the impact of osteoporosis on the elderly population and the consequent costs of health care, together with development of new treatments to prevent fractures, have led to a rapid increase in the demand for bone densitometry measurements. The historical development, their working principles, strengths, and limitations of these technologies will be discussed in this article.