[Quantitative ultrasound. State of the art 1999].

In recent years Quantitative Ultrasound (QUS) approaches have increasingly been used for the assessment of osteoporosis. The development of new technologies has accelerated, and today a number of different devices are commercially available. For a balanced evaluation of the approaches one needs to recognise two issues: There are different applications for QUS, and there are different QUS approaches and devices. Regarding the applications, today the main area for use of QUS approaches is the assessment of a fracture risk. For use in monitoring and diagnosis, further advances and studies are required. Regarding the various approaches, one needs to recognise the differences between the measurement parameters Speed Of Sound (SOS) and Broadband Ultrasound Attenuation (BUA), the different measurement sites and the different technologies employed. Moreover, some of the earlier devices are very well validated whereas newer machines may feature more advanced technology--which, however, needs to be tested and validated. Whatever the choice of a device will be, adequate and regularly performed measures for quality assurance and in-depth knowledge on the general and device specific limitations of the approach are of substantial importance. When used appropriately, QUS devices can play an important role in the assessment of osteoporosis.