Horber F F, Thomi F, Casez J P, Fonteille J, Jaeger P
Policlinic of Medicine, University Hospital, Berne, Switzerland.
Br J Radiol. 1992 Oct;65(778):895-900. doi: 10.1259/0007-1285-65-778-895.
To evaluate the influence of hydration status on the estimation of body composition using dual-energy X-ray absorptiometry (DXA), six normal volunteers and seven patients on maintenance haemodialysis were investigated using two different DXA machines (Lunar DPX, Hologic QDR 1000/W). Normal volunteers were studied (Hologic QDR 1000/W) before and 1 h after ingestion of breakfast, lunch and dinner (drinking various amounts of liquids at each meal, 0.5-2.4 kg). Whereas bone mineral content and body fat mass did not change, lean body mass of the trunk increased as a consequence of the meals. Conversely in patients on haemodialysis (Lunar DPX), lean body mass decreased in all segments of the body as a consequence of removal of 0.9-4.4 kg of salt-containing fluid by haemodialysis (trunk 61%, legs 30%, arms 5.5% and rest of the body 3.5%), whereas bone mineral content and body fat mass remained unchanged. However, this finding(s) did not hold true in one particular patient with bilateral hip prostheses. Measurement of body composition in eight normal volunteers on the same day with both machines showed similar results for lean and fat mass, whereas bone mineral content was found to be 17% higher using the Lunar DPX. In summary, in centres where both machines are available, follow-up of one individual patient should always be performed using the same equipment. In addition, hydration status and food intake must be taken into account when repetitive measurements of lean body mass are performed in the same patient.
为评估水合状态对使用双能X线吸收法（DXA）估算身体成分的影响，我们使用两台不同的DXA机器（Lunar DPX、Hologic QDR 1000/W）对6名正常志愿者和7名维持性血液透析患者进行了研究。正常志愿者在摄入早餐、午餐和晚餐前（使用Hologic QDR 1000/W）以及摄入后1小时进行研究（每餐饮用不同量的液体，0.5 - 2.4千克）。尽管骨矿物质含量和体脂肪量没有变化，但由于进食，躯干的瘦体重增加。相反，在血液透析患者中（使用Lunar DPX），由于血液透析清除了0.9 - 4.4千克含盐液体，身体所有部位的瘦体重均下降（躯干61%、腿部30%、手臂5.5%以及身体其他部位3.5%），而骨矿物质含量和体脂肪量保持不变。然而，这一发现不适用于一名双侧髋关节置换的特定患者。在同一天使用两台机器对8名正常志愿者进行身体成分测量，结果显示瘦体重和脂肪量相似，而使用Lunar DPX测得的骨矿物质含量高17%。总之，在同时拥有这两台机器的中心，对个体患者进行随访时应始终使用同一设备。此外，在对同一患者重复测量瘦体重时，必须考虑水合状态和食物摄入量。
