Kaysen George A, Zhu Fansan, Sarkar Shubho, Heymsfield Steven B, Wong Jack, Kaitwatcharachai Charoen, Kuhlmann Martin K, Levin Nathan W
Renal Research Institute, New York, NY, USA.
Am J Clin Nutr. 2005 Nov;82(5):988-95. doi: 10.1093/ajcn/82.5.988.
Skeletal muscle mass can be measured noninvasively with magnetic resonance imaging (MRI), but this is time-consuming and expensive.
We evaluated the use of multifrequency bioimpedance spectroscopy (BIS) measurements of intracellular volume (ICV) to model total-body skeletal muscle mass (TBMM) and limb skeletal muscle mass in hemodialysis patients.
TBMM was measured by MRI in 20 male and 18 female hemodialysis patients with a median (range) age of 54 y (33-73 y), weight of 78.9 kg (43.2-120 kg), and body mass index (BMI; in kg/m2) of 27.3 (19.4-46.6). We measured total body water (TBW) by using D2O dilution, extracellular volume (ECV) as bromide space, and ICV as TBW minus bromide space. Total body potassium (TBK) measured as 40K was used as an independent model of TBMM. BIS was used to measure whole-body TBW (ankle to wrist) and TBW in the arms and legs. BIS-estimated ICV was used to construct models to calculate limb muscle mass and TBMM. The latter was compared with models derived from isotopic methods.
BIS yielded a model for TBMM [TBMM = 9.52 + 0.331 x ICV + 2.77 (male) + 0.180 x weight (kg) - 0.133 x age] (R2 = 0.937, P < 0.0001) as precise as TBK-measured TBMM [TBMM = 1.29 + 0.00453 x TBK (mEq) + 1.46 (male) + 0.144 x weight (kg) - 0.0565 x age] (R2 = 0.930, P < 0.0001) or isotopic methods. BIS models were also developed for measuring leg and arm muscle mass.
BIS provides an estimate of TBMM that correlates well with isotopic methods in approximating values obtained by MRI and can be used to estimate limb muscle mass.
骨骼肌质量可以通过磁共振成像（MRI）进行无创测量，但这种方法既耗时又昂贵。
我们评估了使用多频生物电阻抗光谱法（BIS）测量细胞内体积（ICV）来建立血液透析患者全身骨骼肌质量（TBMM）和肢体骨骼肌质量模型的可行性。
对20名男性和18名女性血液透析患者进行研究，他们的年龄中位数（范围）为54岁（33 - 73岁），体重为78.9千克（43.2 - 120千克），体重指数（BMI；单位：kg/m²）为27.3（19.4 - 46.6）。通过重水（D2O）稀释法测量总体水（TBW），以溴离子分布空间作为细胞外体积（ECV），以总体水减去溴离子分布空间作为细胞内体积（ICV）。以40K测量的全身钾（TBK）作为全身骨骼肌质量的独立模型。使用BIS测量全身（脚踝到手腕）以及手臂和腿部的总体水。用BIS估算的细胞内体积构建模型来计算肢体肌肉质量和全身骨骼肌质量。将后者与同位素方法得出的模型进行比较。
BIS得出了一个全身骨骼肌质量模型[TBMM = 9.52 + 0.331×ICV + 2.77（男性）+ 0.180×体重（kg） - 0.133×年龄]（R² = 0.937，P < 0.0001），其精确程度与通过全身钾测量的全身骨骼肌质量模型[TBMM = 1.29 + 0.00453×TBK（毫当量）+ 1.46（男性）+ 0.144×体重（kg） - 0.0565×年龄]（R² = 0.930，P < 0.0001）或同位素方法相当。还开发了用于测量腿部和手臂肌肉质量的BIS模型。
BIS提供的全身骨骼肌质量估计值与同位素方法密切相关，在近似MRI获得的值方面表现良好，并且可用于估计肢体肌肉质量。
