Aloia J F, Vaswani A, Ma R, Flaster E
Department of Medicine, Winthrop-University Hospital, Mineola, New York 11501, USA.
J Nucl Med. 1995 Aug;36(8):1392-7.
Dual-energy x-ray absorptiometry (DEXA) is a readily available technique that has recently been applied to measurement of body composition. In order to validate this technique, results from DEXA were compared with fat-free mass (FFM) and fat mass (FM) measured by total body levels of potassium (TBK), nitrogen (TBN), water (TBW) and carbon (TBC).
A healthy population of 127 white women and 38 black women with a body mass index of 18-30 were recruited.
Compared with each of the other methods, DEXA overestimated FM and underestimated FFM. The slopes of the FM by DEXA versus the FM from each of the four methods were approximately the same, with a s.e.e. ranging from 2.4 to 3.0 units. The slopes of DEXA in comparison to FFM, however, ranged from 0.61 to 0.74 and were significantly less than unity, with a s.e.e. of 1.6 to 2.4 units.
These findings suggest that at high values of FFM, DEXA is measuring something different from the FFM measured by TBW, TBN and TBK. The program for separating bone and soft tissue and for separating soft tissue into fat and lean at higher values in the DEXA method may need to be adjusted.
双能X线吸收法（DEXA）是一种易于使用的技术，最近已应用于身体成分测量。为了验证该技术，将DEXA的结果与通过全身钾（TBK）、氮（TBN）、水（TBW）和碳（TBC）水平测量的去脂体重（FFM）和脂肪量（FM）进行了比较。
招募了127名体重指数为18 - 30的白人女性和38名黑人女性组成的健康人群。
与其他每种方法相比，DEXA高估了FM并低估了FFM。DEXA测量的FM与四种方法中每种方法测量的FM的斜率大致相同，标准误范围为2.4至3.0单位。然而，DEXA与FFM相比的斜率范围为0.61至0.74，明显小于1，标准误为1.6至2.4单位。
这些发现表明，在FFM值较高时，DEXA测量的是与通过TBW、TBN和TBK测量的FFM不同的东西。DEXA方法中用于分离骨骼和软组织以及在较高值时将软组织分离为脂肪和瘦肉的程序可能需要调整。
