title: Portable A-Mode Ultrasound for Body Composition Assessment in Adolescents.
abstract: OBJECTIVE
  Ultrasound (US) imaging is a low-cost, highly feasible alternative method for monitoring the nutritional status of a population; however, only a few studies have tested the body composition agreement between US and reference standard methods, especially in adolescents. The purposes of this study were to assess the agreement of portable US with a reference standard method, dual-energy x-ray absorptiometry (DXA), for body fat percentage (BF%) in adolescents and to verify whether the use of a new mathematical model, based on the anatomic thickness obtained by US, is capable of improving BF% prediction.
  
  
  METHODS
  This research was a descriptive study. Measures of total body mass, BF% on DXA, and BF% on US were collected from 105 adolescents.
  
  
  RESULTS
  The participants included 71 male adolescents (median age ± interquartile range, 14.0 ± 2.0 years) and 34 female adolescents (13.0 ± 2.3 years). Ultrasound yielded significantly lower BF% values than DXA for male (mean ± SD, US, 9.6% ± 6.6%; DXA, 20.0% ± 7.2%; R= 0.848; P< .05) and female (US, 22.5% ± 5.7%; DXA, 30.3% ± 4.9%; R = 0.495; P < .05) participants. In addition, Bland-Altman analysis showed low concordance. When a multivariate regression was tested, the results improved for both sexes (US, 20.3% ± 4.6%; R= 0.848; P= .503) and female participants (US, 29.0% ± 5.7%; R = 0.712; P = .993) with a standard estimate of error of 1.57%.
  
  
  CONCLUSIONS
  This study has shown that US applied in a specific regression for BF% prediction in adolescents has a strong correlation with DXA as well as concordance with Bland-Altman analysis.
authors.affiliation: Graduate Program in Electrical and Computer Engineering, Federal University of Technology-Paraná, Curitiba, Brazil.
authors.forename: Wagner Luis
authors.initials: WL
authors.lastname: Ripka
authors.affiliation: Graduate Program in Biomedical Engineering, Federal University of Technology-Paraná, Curitiba, Brazil.
authors.forename: Leandra
authors.initials: L
authors.lastname: Ulbricht
authors.affiliation: Graduate Program in Biomedical Engineering, Federal University of Technology-Paraná, Curitiba, Brazil.
authors.forename: Lucas
authors.initials: L
authors.lastname: Menghin
authors.affiliation: Graduate Program in Electrical and Computer Engineering, Federal University of Technology-Paraná, Curitiba, Brazil.
authors.forename: Pedro Miguel
authors.initials: PM
authors.lastname: Gewehr
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging*; D000293:Adolescent; D001823:Body Composition; D001837:Body Weights and Measures / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods*
keywords: adolescents; body composition; dual-energy x-ray absorptiometry; fat mass; ultrasound