Applications of bone densitometry for osteoporosis.

Over the past decade, growing awareness of the impact of osteoporosis on the elderly population and the availability of new treatments to prevent fractures have stimulated the rapid development of new radiologic techniques to assist in diagnosis. With the ability to perform high precision measurements of bone mineral density (BMD) in the spine and hip, dual X-ray absorptiometry (DXA) is well suited to meet this latter need. However, there is continuing interest in smaller, cheaper systems for assessing the peripheral skeleton that include DXA scanning of the distal forearm and a variety of devices for performing quantitative ultrasound (QUS) measurements on bone. Alongside the new equipment, new guidelines have been developed to assist in the interpretation of bone densitometry studies and, following a report by a World Health Organization working group, osteoporosis is increasingly diagnosed on the basis of the patient's T-score value (difference of BMD from young adult mean normalized to the population SD). For the future, wider provision of bone densitometry services is required to properly target the new treatments now becoming available. Since it is unlikely that conventional DXA can meet these needs, QUS is an attractive alternative, especially because this technique is now proven in its ability to predict fracture risk in the elderly and FDA approval is imminent.