Endocrine Abstracts

Areal BMD from Dual energy X-Ray absorptiometry (DXA) accounts for approximately two-thirds of bone strength and is used as a surrogate for bone strength in clinical practice to predict fracture risk. Nevertheless, a more in-depth assessment of bone quality requires second level imaging techniques to assess bone quality parameters. Bone quality is a key parameter in determining bone strength. During time, several non-invasive high-resolution imaging techniques have been developed to visualise bone structure. As bony trabeculae measure 50–200 μm in thickness, the spatial resolution of imaging techniques applied to the the non-invasive evaluation of bone microstructure must be higher than 200 μm to spatially solve the single trabeculae. High-resolution peripheral quantitative computed tomography (HR-pQCT) is a low-dose technique that enable to image bone microarchitecture in vivo at peripheral skeletal sites, such as distal forearm and tibia. Differences and reference data exist for HR-pQCT by age and sex, race/ethnic origin and body composition. We will review the role of HR-pQCT in fractured patients, to highlight those parameters of bone microarchitecture and bone strength useful as predictors of incident fractures, as well as in subject with prevalent fractures. The role of HR-pQCT in monitoring response of anti-osteoporotic therapy will be addressed, as well as its role in patients with secondary osteoporosis and metabolic bone disorders. Finally, novel application of Hr-pQCT will be briefly reviewed. The presentation will then deal with the evaluation and quantification of bone structure and microstructure with current available MRI techniques, also comparing the MRI performance with DXA and CT measurements. Limitation of each technique will be reviewed, as well as their current applicability in clinical practice.