Margulies Lauren, Horlick Mary, Thornton John C, Wang Jack, Ioannidou Elli, Heymsfield Steven B
Body Composition Unit, St. Luke's-Roosevelt Hospital, and Columbia University, New York, NY 10025, USA.
J Clin Densitom. 2005 Fall;8(3):298-304. doi: 10.1385/jcd:8:3:298.
The use of dual-energy X-ray absorptiometry (DXA) in pediatrics is increasing. It is safe, readily available, and easily performed, but there is little information on reproducibility. The aim of this study is to evaluate the reproducibility of whole body DXA scans in children. Total and regional bone mineral density, bone mineral content, nonbone, lean fat mass, and percent fat were measured twice by whole body DXA (GE Lunar Prodigy) in 49 subjects (5 to 17 yr). Within each subject, between subjects, and reading standard deviations for each body component were evaluated as well as intraclass correlations (IC) and coefficients of variation (CV). Total body measurements had better IC and CV than regional results from the whole body scan, with legs and arms better than trunk and spine. IC values were >or=0.989 for total body, >or=0.976 for legs and arms, and >or=0.875 for trunk and spine. CV values ranged 0.18 to 1.97% for total body, and 0.96 to 6.91% for regional measures. These values confirm that body composition and bone mass by DXA are highly reproducible among pediatric subjects. The results of this study can be used by clinicians and researchers for interpretation of longitudinal observations and for power calculations.
双能X线吸收法（DXA）在儿科中的应用正在增加。它安全、易于获得且操作简便，但关于其可重复性的信息较少。本研究的目的是评估儿童全身DXA扫描的可重复性。对49名受试者（5至17岁）使用全身DXA（GE Lunar Prodigy）测量了全身及局部的骨矿物质密度、骨矿物质含量、非骨组织、瘦体重、脂肪量和脂肪百分比，各测量两次。评估了每个受试者内部、不同受试者之间以及每个身体成分的读数标准差，以及组内相关系数（IC）和变异系数（CV）。全身测量的IC和CV优于全身扫描的局部结果，腿部和手臂的结果优于躯干和脊柱。全身的IC值≥0.989，腿部和手臂的IC值≥0.976，躯干和脊柱的IC值≥0.875。全身的CV值范围为0.18%至1.97%，局部测量的CV值范围为0.96%至6.91%。这些值证实了DXA测量的身体成分和骨量在儿科受试者中具有高度可重复性。本研究结果可供临床医生和研究人员用于纵向观察的解释和功效计算。
