Osteoporosis Clinical Research Program, University of Wisconsin, Madison, WI, USA.
Osteoporosis Clinical Research Program, University of Wisconsin, Madison, WI, USA.
J Clin Densitom. 2018 Apr-Jun;21(2):303-307. doi: 10.1016/j.jocd.2017.08.003. Epub 2017 Oct 5.
External artifacts can confound dual-energy X-ray absorptiometry (DXA) measurements. It is often accepted that garments free of metal do not affect DXA results; however, little data exist in this regard. It is plausible that some textiles absorb radiation and thereby alter DXA results. We hypothesized that some dense or synthetic textiles, for example, reflective materials, might alter DXA-measured bone and soft tissue mass. Hologic and GE Lunar spine phantoms and a Bioclinica prototype total body phantom were imaged on a GE Lunar iDXA and Prodigy densitometer. Each phantom was scanned 10 times to establish mean values. Subsequently, 2 layers of various fabrics were placed over the entire top surface of the phantom, and 10 scans were performed without repositioning. Samples of natural, synthetic, or embellished fabric (including those with reflective material) and of varying thickness were used. Wilcoxon signed rank tests were used to compare the means between bare phantom and textile-covered phantom. Significant differences were demonstrated often, depending on the scanner, phantom, and textile used. A polyester fabric with reflective strip consistently altered measurements. For example, this fabric increased measured mean lumbar spine bone mineral density and total body bone mineral content by 0.008 g/cm and 3.6 g, respectively (p < 0.01). Similarly, mean total body fat decreased (-173 g) and lean mass increased (+213 g; p < 0.01). Fat and lean mass were also affected by metallic thread, wool, blend denim, and shiny polyester (p < 0.05), and lean mass was affected by cotton denim and sweatshirt material (p < 0.0003). In conclusion, textiles can affect DXA-measured bone mineral density and body composition results. Even small amounts of reflective material could alter mass measurements by ~25% of the least significant change. Clothing made of dense textiles (e.g., wool and denim) or those with reflective material and metallic thread should be avoided during DXA scanning.
外部伪影会干扰双能 X 射线吸收法（DXA）的测量。人们通常认为，不含金属的衣物不会影响 DXA 结果；然而，这方面的数据很少。一些纺织品可能会吸收辐射，从而改变 DXA 的结果。我们假设，一些高密度或合成纺织品，例如反光材料，可能会改变 DXA 测量的骨和软组织质量。Hologic 和 GE Lunar 脊柱体模和 Bioclinica 原型全身体模在 GE Lunar iDXA 和 Prodigy 骨密度仪上进行成像。每个体模扫描 10 次以建立平均值。随后，在体模的整个顶表面放置 2 层各种织物，并在不移位的情况下进行 10 次扫描。使用了天然、合成或装饰性的织物（包括反光材料）的各种样本，厚度也各不相同。Wilcoxon 符号秩检验用于比较裸体模和覆盖有织物的体模之间的平均值。根据使用的扫描仪、体模和织物，往往会显示出显著的差异。一种带有反光条的聚酯织物始终会改变测量结果。例如，这种织物使测量的腰椎骨矿物质密度和全身骨矿物质含量分别增加了 0.008 g/cm 和 3.6 g（p < 0.01）。同样，平均全身脂肪量减少了（-173 克），瘦体重增加了（+213 克；p < 0.01）。脂肪和瘦体重也受到金属线、羊毛、混纺牛仔布和闪亮聚酯的影响（p < 0.05），而瘦体重受到棉牛仔布和运动衫材料的影响（p < 0.0003）。总之，纺织品会影响 DXA 测量的骨矿物质密度和身体成分结果。即使是少量的反光材料也可能会使质量测量值改变约最小有意义变化的 25%。在 DXA 扫描期间，应避免使用高密度纺织品（如羊毛和牛仔布）或反光材料和金属线制成的衣物。
