Sarcopenia is defined as the loss of muscle mass or function and has been associated with increased morbidity and mortality in a variety of diseased populations. Sarcopenia results from a higher rate of muscle protein degradation compared to protein synthesis and is an important marker of metabolic status related to nutrition and physical activity. The diagnosis of sarcopenia is accomplished by clinical assessment demonstrating decreased muscle function and radiographic confirmation of decreased muscle mass, via dual X-ray absorptiometry, bioelectric impedance or cross-sectional imaging with CT or MRI. However, normative data for skeletal muscle mass are lacking, especially for children and young adults. Additionally, studies of skeletal muscle mass by cross-sectional imaging in children are scarce. Here, we review the concept of sarcopenia with an emphasis on its relevance in the pediatric population.

中文翻译：

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骨骼肌质量的量化：肌肉减少症是儿童和成人总体健康的标志。

肌肉减少症被定义为肌肉质量或功能的丧失，并与各种患病人群的发病率和死亡率增加相关。与蛋白质合成相比，肌肉减少症是由于肌肉蛋白质降解率更高，并且是与营养和身体活动有关的代谢状态的重要标志。肌肉减少症的诊断是通过临床评估来完成的，该评估通过双X线吸收法，生物电阻抗或CT或MRI断层成像来证明肌肉功能下降，并通过射线照相证实肌肉质量下降。但是，缺乏骨骼肌质量的规范数据，尤其是对于儿童和年轻人。此外，通过横截面成像对儿童进行骨骼肌质量的研究很少。这里，