骨质疏松管理进展教材.pptVIP

Quantitative ultrasonography (QUS)?—? does not measure BMD, but instead measures the transmission of ultrasound through accessible limb bones or the reflectance of the ultrasound waves from the bone surface. Quantitative computed tomography? (QCT): measures volumetric BMD (vBMD) in mg/cm3, most often at the spine. Unlike DXA, QCT can isolate trabecular bone from its envelope of cortical bone. The studies are split regarding its superiority to DXA. Emerging technologies?: High resolution microCT and microMRI allow noninvasive three-dimensional evaluation of bone microarchitecture. These techniques are used primarily in research settings. Other imaging techniques: ?In 2008, a WHO task force introduced a Fracture Risk Assessment Tool (FRAX), which estimates the 10-year probability of hip fracture or major osteoporotic fractures combined (hip, spine, shoulder, or wrist) for an untreated patient using femoral neck T-score or Z-score and easily obtainable clinical risk factors for fracture 50. FRAX is based upon data collected from large prospective observational studies of men and women of different ethnicities and from different world regions in which clinical risk factors, BMD, and fractures were evaluated 51,52 . FRAX has been validated in 11 independent cohorts, mainly comprised of women 53. The statistical power of this large dataset allows estimation of fracture probability from an individuals set of risk factors. The country-specific FRAX prediction algorithm is available online at (http://www.shef.ac.uk/FRAX/). 54 In the United States, cost-effectiveness modeling suggests that the 10-year hip fracture probability at which treatment becomes cost-effective (intervention threshold) ranges from 2.5 to 4.7 percent for women and from 2.4 to 4.9 percent in men, depending upon age and assuming annual treatment costs of $600 and a willingness-to-pay threshold of $60,000 . 55 FRAX score Uses: They can give some indication about the future risk for bone loss and fr