[Usefulness of bone densitometry, quantitative computed tomography and quantitative ultrasound in diagnosis and monitoring of osteoporosis treatment].

Bone densitometry is characterized by high sensitivity and specificity in osteoporosis, and new generations of densitometers enable measurements with improved intra- and inter-assay precision. The clinical potential of bone densitometry is well documented and the technique is widely used in clinical practice. It does not, however, allow for measurement of "true" bone density; instead it measures so called serial density (expressed in g/cm2) which is the distribution of bone mass over the flat projection of the skeleton. Limitations of densitometric techniques can be overcome by applying other methods, i.e. quantitative computed tomography (QCT) and ultrasound (US). QCT enables separate measurements of compact and trabecular bone density (expressed in g/cm3), as well as calculation of Strength-Strain Index (SSI), reflecting the mechanical resistance of bone to fracture. US is a non-invasive technique, providing information of fracture risk and bone tissue quality. Both techniques seem very promising and have been extensively studied recently; they are expected to move from clinical research to clinical practice soon.