Blake G M, Fogelman I
Department of Nuclear Medicine, Guy's Hospital, London, United Kingdom.
Semin Nucl Med. 1997 Jul;27(3):248-60. doi: 10.1016/s0001-2998(97)80027-x.
Dual-energy x-ray absorptiometry (DXA) is widely used for identifying patients with osteoporosis, making decisions about the commencement of preventive therapy, and following up response to treatment. It is important that radiologists and nuclear medicine physicians issuing clinical reports present clear interpretations that aid the primary care physician in making decisions affecting treatment. This review discusses the principles behind the interpretation of bone mineral density (BMD) studies. After a World Health Organization report published in 1994, osteoporosis is often diagnosed on the basis of the patient's T-score value (difference of BMD from young adult mean normalized to the population SD). T-scores are a measure of current fracture risk. There are problems relating to the use of T-scores in the elderly, and we argue that decisions about treatment are generally best made on the basis of the Z-score value (difference of BMD from age-matched mean normalized to the population SD) because this measures the patient's fracture risk relative to his or her peers. Recent studies confirm that the posteroanterior (PA) projection lumbar spine scan is still the optimum measurement site for monitoring response to treatment. A BMD change of 4.5% is required to register a statistically significant change.
双能X线吸收法（DXA）被广泛用于识别骨质疏松症患者、决定预防性治疗的开始以及跟踪治疗反应。出具临床报告的放射科医生和核医学医生给出清晰的解读很重要，这有助于初级保健医生做出影响治疗的决策。本综述讨论了骨密度（BMD）研究解读背后的原理。1994年世界卫生组织发布报告后，骨质疏松症常根据患者的T值（BMD与年轻成人平均值之差，经人群标准差标准化）进行诊断。T值是当前骨折风险的一种度量。在老年人中使用T值存在问题，我们认为治疗决策通常最好基于Z值（BMD与年龄匹配平均值之差，经人群标准差标准化）做出，因为这衡量了患者相对于其同龄人骨折的风险。最近的研究证实，后前位（PA）腰椎扫描仍是监测治疗反应的最佳测量部位。需要4.5%的BMD变化才能记录有统计学意义的变化。
