Biomechanics Laboratory, School of Sports, Center of Sports, Federal University of Santa Catarina, Florianópolis, SC 88040-900, Brazil.
Biomechanics Laboratory, School of Sports, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil; Department of Morphological Sciences, School of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil.
Appl Physiol Nutr Metab. 2021 May;46(5):473-478. doi: 10.1139/apnm-2020-0413. Epub 2020 Nov 6.
We aimed to provide an unbiased estimate of the confounding effect of subcutaneous fat thickness on ultrasound echo intensity (EI) measures of muscle quality. The effect of fat thickness on EI was verified for an approximate range of 0 to 3 cm of fat using exogeneous layers of pork fat over the human tibialis anterior muscle. Sonograms were obtained () with focus constant across fat thickness conditions, and () with focus position adjusted to the muscle region of interest (ROI) position for each fat thickness level. In agreement with our hypothesis, increasing fat between the probe and the ROI resulted in a decrease in EI. This overestimating effect of fat on muscle quality differs between sonograms with constant focus and sonograms with focus position adjusted to the vertical displacement in ROI position that occurs for different levels of fat thickness. Correcting equations to account for the overestimating effect of fat on muscle quality are provided for both focus conditions. This is the first study to systematically analyze the confounding effect of fat thickness as an independent factor and the provided equations can be used for improved accuracy in estimates of muscle quality in obese/overweight subjects/patients. The independent confounding effect of subcutaneous fat thickness on ultrasound (US) estimates of muscle quality was quantified. US estimates of muscle quality depend on whether focus is adjusted to the muscle region of interest or not. Equations for correcting muscle quality estimates are provided.
我们旨在提供一个无偏估计的混杂效应的皮下脂肪厚度对超声回波强度（EI）的肌肉质量措施。脂肪厚度对 EI 的影响进行了验证，近似范围为 0 至 3 厘米的脂肪使用外源性层猪肉前胫骨肌肉。声像图（）与重点不变脂肪厚度条件下，（）与重点位置调整到感兴趣的肌肉区域（ROI）的位置为每一个脂肪厚度水平。与我们的假设一致，增加脂肪之间的探头和 ROI 导致 EI 下降。这种高估脂肪对肌肉质量的影响之间的差异声像图与重点位置不变和 sonograms 调整到垂直位移 ROI 位置发生不同层次的脂肪厚度。校正方程，以弥补高估脂肪对肌肉质量的影响提供了两种重点条件。这是第一项研究系统地分析了混杂效应的脂肪厚度作为一个独立的因素和所提供的方程可用于提高准确性估计肌肉质量在肥胖/超重 subject/patients。皮下脂肪厚度对超声（超声）估计的肌肉质量的独立混杂效应进行了量化。超声估计的肌肉质量取决于是否重点调整到肌肉的感兴趣区域或不。方程提供了纠正肌肉质量估计。
