Assessment of EchoMRI-AH versus dual-energy X-ray absorptiometry by iDXA to measure human body composition (original) (raw)

Background-Comparison of percent fat mass across different body composition analysis devices is important given variation in technology accuracy and precision, as well as the growing need for cross-validation of devices often applied across longitudinal studies. Subjects/Methods-We compared EchoMRI-AH and Lunar iDXA quantification of percent body fat (PBF) in 84 adults (43M, 41F) with mean age 39.7±15.9 y and BMI 26.2±5.3 kg/m 2. Results-PBF correlated strongly between devices (r>0.95, p<0.0001). A prediction equation was derived in half of the subjects, and the other half were used to cross-validate the proposed equation (EchoMRI-AH PBF=[0.94*iDXA PBF]+[0.14*Age]+[3.3*Female]−8.83). Mean PBF difference (predicted-measured) in the validation group was not different from 0 (diff=0.27%, 95%CI: −0.42-0.96, p=0.430). Bland-Altman plots showed a bias with higher measured PBF on EchoMRI-AH versus iDXA in all 84 subjects (β=0.13, p<0.0001). Conclusions-The proposed prediction equation was valid in our cross-validation sample, and has the potential to be applied across multicenter studies.