Picaud J C, Rigo J, Nyamugabo K, Milet J, Senterre J
Department of Neonatology, University of Liège, Belgium.
Am J Clin Nutr. 1996 Feb;63(2):157-63. doi: 10.1093/ajcn/63.2.157.
The reproducibility, accuracy, and precision of dual-energy X-ray absorptiometry (DXA) was assessed by scanning 13 piglets (1471-5507 g) in triplicate. In four piglets, fat content was increased with porcine lard around the abdomen; additional measurements were performed on these animals. Reproducibility in DXA measurements from the animals without added fat was 0.09% for body weight, 1.95% for bone mineral content (BMC), and 5.35% for fat content. DXA estimates of body weight, BMC, and fat content were significantly correlated with scale body weight, ash weight, chemical calcium, and chemical fat. Body weight was measured accurately but fat content was overestimated by DXA. Mean BMC estimated by DXA represented 48% of ash weight and 215% of calcium content. The precision of DXA was 0.23% for body weight, 10.99% for ash weight, and 4.44% for calcium content. The precision of DXA for fat content was poor. However, for measurements performed in piglets with > 250 g fat, the precision was 8.85%. Thirty appropriate-forgestational-age term human neonates (birth weight: 3188 +/- 217 g) were scanned once during the first week of life. BMC and fat content were 54 +/- 6 and 470 +/- 92 g, respectively, which corresponded to 26.4 +/- 2.6 g calcium and 427 +/- 82 g fat. These were close to the reference values previously determined by chemical analysis. This study suggests that DXA is accurate and reliable for measurement of calcium and fat contents in human neonates. Further refinements would be beneficial for determining fat content in preterm human infants.
通过对13头体重1471 - 5507克的仔猪进行三次扫描，评估了双能X线吸收法（DXA）的可重复性、准确性和精密度。在4头仔猪中，通过在腹部周围涂抹猪油增加脂肪含量；对这些动物进行了额外测量。未添加脂肪的动物DXA测量的体重可重复性为0.09%，骨矿物质含量（BMC）为1.95%，脂肪含量为5.35%。DXA对体重、BMC和脂肪含量的估计与秤量体重、灰分重量、化学钙和化学脂肪显著相关。体重测量准确，但DXA高估了脂肪含量。DXA估计的平均BMC占灰分重量的48%，钙含量的215%。DXA的精密度对于体重为0.23%，灰分重量为10.99%，钙含量为4.44%。DXA对脂肪含量的精密度较差。然而，对于体重超过250克脂肪的仔猪进行测量时，精密度为8.85%。对30名足月适于胎龄的新生儿（出生体重：3188±217克）在出生后第一周进行了一次扫描。BMC和脂肪含量分别为54±6克和470±92克，分别对应26.4±2.6克钙和427±82克脂肪。这些数值接近先前通过化学分析确定的参考值。本研究表明，DXA对于测量人类新生儿的钙和脂肪含量是准确可靠的。进一步改进对于确定早产儿的脂肪含量将是有益的。
