Quantitative ultrasonometry (QUS) for the evaluation of osteoporosis risk: reference data for various measurement sites, limitations and application possibilities.

Osteoporosis is a wide-spread disease characterized by low bone mass, deterioration of bone structure and typical fractures, which lead to pain, disability and high costs for health systems. Quantitative Ultrasonometry (QUS) is a new, non-invasive method to study bone density and structure in vivo. This technique has the following advantages: it is safe; it is easy to use, there is no radiation load on the patient, and instruments can be transported and are relatively cheap, as compared with the substantially more expensive methods of traditional osteodensitometry (dual X-ray absorptiometry = DXA, quantitative computed tomography = QCT). For measuring the osteoporosis risk, QUS has the same value as the conventional radiological osteodensitometry methods (QCT, DXA) The combination ofQUS, DXA and QCT improves the message. At present, there are three measurement sites for QUS measurement at the skeleton: the calcaneus, the tibia and the phalanges. The oldest method is the calcaneus measurement, and instruments with and without a water bath are available for this purpose. QUS might be a screening method for osteoporosis. Currently QUS can already be used in clinical practice. It can, for example, be an aid in decision-making for female patients who do not wish to have a postmenopausal hormone replacement therapy (HRT) or who can only barely tolerate doses with a bone-protective effect. In addition, patients can be examined before and after a glucocorticoid therapy with regard to a possible loss in bone mass. As a third possibility, QUS provides a further opportunity for subdividing into development stages patients with an established osteoporosis resulting in fractures, since there is an indication that by means of QUS it may be possible to account for more structural bone changes than with the traditional DXA or QCT methods. Treatment can also be monitored by means of QUS. As prospective studies have shown, increases in SOS by HRT and alendronate and precision error of QUS are lower than expected changes. Due to the greater practicability of QUS (no radiation load, portable instruments), this method ought to be further used in research and clinical settings, and more experience ought to be collected with this method so that wide-ranging experience can help the management of our patients.