A Foundational Study on Novel Body Composition Assessment Using Ultrasound in Para-Athletes with Amputee

Abstract

Purpose The purpose of this study was to examine the validity of subcutaneous fat thickness （SFT） and qualitative muscle assessment using ultrasound, and to further investigate their relationships with phase angle （PhA） derived from bioelectrical impedance analysis （BIA）． Methods Twenty-one individuals （16 males and 5 females） who underwent CT scans at our institution were included. Subcutaneous fat thickness was measured at the thigh, upper arm, and waist using ultrasound （US-SFT） and CT images （CT-SFT）．At the thigh, echo intensity （EI） from ultrasound and CT attenuation values were obtained to assess muscle quality, and their correlations with PhA were analyzed. Pearson’s or Spearman’s correlation coefficients were used for statistical analyses. Results A very strong positive correlation was observed between US-SFT and CT-SFT, confirming the validity of ultrasound for measuring subcutaneous fat thickness. A significant negative correlation was also found between lower-limb PhA and both US-SFT and CT-SFT, indicating a localized relationship between subcutaneous fat and PhA. Regarding muscle quality, CT values showed a significant positive correlation with PhA, whereas EI demonstrated only a limited association. Conclusion Ultrasound-derived subcutaneous fat thickness （US-SFT） provides an accurate estimate comparable to that of CT and may serve as a useful alternative indicator, especially for individuals such as those with limb amputation, in whom BIA is difficult to apply. Conversely, for qualitative muscle assessment, CT demonstrated superiority, highlighting the importance of selecting assessment modalities based on specific evaluation goals.