Department of Radioimmunology, Biochemistry, and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland.
J Clin Densitom. 2013 Oct-Dec;16(4):562-9. doi: 10.1016/j.jocd.2013.01.003. Epub 2013 Feb 26.
Dual-energy X-ray absorptiometry (DXA) method is widely used in pediatrics in the study of bone density and body composition. However, there is a limit to how precise DXA can estimate bone and body composition measures in children. The study was aimed to (1) evaluate precision errors for bone mineral density, bone mass and bone area, body composition, and mechanostat parameters, (2) assess the relationships between precision errors and anthropometric parameters, and (3) calculate a "least significant change" and "monitoring time interval" values for DXA measures in children of wide age range (5-18yr) using GE Lunar Prodigy densitometer. It is observed that absolute precision error values were different for thin and standard technical modes of DXA measures and depended on age, body weight, and height. In contrast, relative precision error values expressed in percentages were similar for thin and standard modes (except total body bone mineral density [TBBMD]) and were not related to anthropometric variables (except TBBMD). Concluding, due to stability of percentage coefficient of variation values in wide range of age, the use of precision error expressed in percentages, instead of absolute error, appeared as convenient in pediatric population.
双能 X 射线吸收法（DXA）广泛应用于儿科研究骨密度和身体成分。然而，DXA 在估计儿童的骨骼和身体成分方面的精确性存在一定的限制。本研究旨在：(1) 评估骨矿物质密度、骨量和骨面积、身体成分和力学参数的精密度误差；(2) 评估精密度误差与人体测量参数之间的关系；(3) 使用 GE Lunar Prodigy 密度仪计算年龄范围广泛（5-18 岁）的儿童的 DXA 测量的“最小显著变化”和“监测时间间隔”值。研究结果表明，DXA 测量的薄和标准技术模式的绝对精密度误差值不同，且取决于年龄、体重和身高。相比之下，以百分比表示的相对精密度误差值在薄和标准模式下相似（除全身骨矿物质密度 [TBBMD] 外），且与人体测量变量无关（除 TBBMD 外）。综上所述，由于在广泛的年龄范围内百分比变异系数值的稳定性，使用百分比表示的精密度误差，而不是绝对误差，在儿科人群中似乎更为方便。
