Adams J E
Department of Diagnostic Radiology, University of Manchester, UK.
Curr Opin Radiol. 1992;4(6):11-20.
Osteoporosis is a common cause of vertebral and hip fractures and although their occurrence depends on a variety of factors, bone mineral density (BMD) is the most important determinant. Methods of measuring BMD are therefore pertinent to identify individuals with reduced bone mass and at increased risk of fracture, and current techniques provide accurate and precise BMD measurements with low radiation dose. The methods most widely used are single photon absorptiometry; dual photon absorptiometry, which has been replaced by dual energy x-ray absorptiometry; and quantitative CT. Dual energy x-ray absorptiometry permits BMD measurement in the lumbar spine, femoral neck, forearm, and whole body. Bone strength is also related to trabecular width and arrangement. The newer techniques of broadband ultrasound attenuation and MR imaging (T2*) offer potential for investigating both trabecular bone mass and structure, as does high-resolution CT. These methods provide powerful tools for the study of the skeleton in health and disease and have established roles in appropriate clinical circumstances. Although BMD measurement can provide an estimate of fracture risk, there are limitations to fracture prediction in an individual subject, but efforts are being made to improve the discriminatory and predictive aspects of BMD.
骨质疏松症是导致脊椎和髋部骨折的常见原因,尽管骨折的发生取决于多种因素,但骨密度(BMD)是最重要的决定因素。因此,测量骨密度的方法对于识别骨量减少和骨折风险增加的个体至关重要,目前的技术能够以低辐射剂量提供准确、精确的骨密度测量结果。最广泛使用的方法有单光子吸收法;双光子吸收法,现已被双能X线吸收法取代;以及定量CT。双能X线吸收法可用于测量腰椎、股骨颈、前臂和全身的骨密度。骨强度还与骨小梁宽度和排列有关。宽带超声衰减和磁共振成像(T2*)等新技术为研究骨小梁骨量和结构提供了可能,高分辨率CT也是如此。这些方法为研究健康和疾病状态下的骨骼提供了有力工具,并在适当的临床情况下发挥着既定作用。虽然骨密度测量可以提供骨折风险的估计值,但在个体受试者中进行骨折预测存在局限性,不过目前正在努力改进骨密度的鉴别和预测能力。