[Recent development and clinical application of bone mineral measurements]

Over the past decade, methodologies for the assessment of bone mineral density have markedly progressed, so that any sites of the skeleton now can be measured with high degree of accuracy and precision with safety. The number of devices distributed in Japan rapidly increased for the last 5 years and the total number installed nationwide reached over 7000 as with 1998. There are variety of techniques: microdensitometry (MD) or radiographic absorptiometry (RA), single X-ray absorptiometry (SXA), dual X-ray absorptiometry (DXA), quantitative CT (QCT), peripheral QCT, and quantitative ultrasonometry (QUS). There are, however, no such single technique as to fulfill the entire clinical requirements, since the time of initiation of bone loss, and the speed of bone loss are quite different from site to site of the skeleton, so that the correlations of bone density measured by each technique are not sufficiently high (gamma = 0.5-0.8) to predict BMD of other bones by measuring one bone. Since the relatively large amounts of data on the prediction of fracture (hip, spine and others) by these techniques have been accumulated, a specific guideline regarding the appropriate application of these techniques, including multiple combination measurements, should be established based on the worldwide consensus.