An update on the assessment of osteoporosis using radiologic techniques.

In this article, the currently available radiologic techniques for assessing osteoporosis are reviewed. Density measurements of the skeleton using dual X-ray absorptiometry (DXA) are clinically indicated for the assessment of osteoporosis and for the evaluation of therapies. DXA is the most widely used technique for identifying patients with osteoporosis. Quantitative computed tomography (QCT) is the only method, which provides a volumetric density. Unlike DXA, QCT allows for selective trabecular measurement and is less sensitive to degenerative diseases of the spine. The analysis of bone structure in conjunction with bone density is an exciting new field in the assessment of osteoporosis. High-resolution multi-slice CT and micro-CT are useful tools for the assessment of bone microarchitecture. A growing literature indicates that quantitative ultrasound (QUS) techniques are capable of assessing fracture risk. Although the ease of use and the absence of ionizing radiation make QUS attractive, the specific role of QUS techniques in clinical practice needs further determination. Considerable progress has been made in the development of MR techniques for assessing osteoporosis during the last few years. In addition to relaxometry techniques, high-resolution MR imaging, diffusion MR imaging and in-vivo MR spectroscopy may be used to quantify trabecular bone architecture and mineral composition.