Validation of a Quantitative Magnetic Resonance Method for Measuring Human Body Composition

• Published in: Obesity (Silver Spring, Md.) Md.), 2008-01, Vol.16 (1), p.191-198
• Main Authors: Napolitano, Antonella, Miller, Sam R, Murgatroyd, Peter R, Coward, W. Andrew, Wright, Antony, Finer, Nick, De Bruin, Tjerk W, Bullmore, Edward T, Nunez, Derek, J
• Format: Article
• Language: English
• Subjects: Absorptiometry, Photon; Accuracy; adipocytes; adipose tissue; Adiposity; anthropometric measurements; Body Composition; Body fat; Body Mass Index; Body Water; Canola; fat free mass; fat mass measurement; Female; Hospitals; Human subjects; Humans; Magnetic Resonance Imaging - methods; Male; Metabolism; Methods; nuclear magnetic resonance spectroscopy; Nutrition research; Obesity; overweight; pandemic; Reproducibility of Results; validity; Weight control
• ISSN: 1930-7381; 1930-739X
• DOI: 10.1038/oby.2007.29

Objective: To evaluate a novel quantitative magnetic resonance (QMR) methodology (EchoMRI‐AH, Echo Medical Systems) for measurement of whole‐body fat and lean mass in humans. Methods and Procedures: We have studied (i) the in vitro accuracy and precision by measuring 18 kg Canola oil with and without 9 kg water (ii) the accuracy and precision of measures of simulated fat mass changes in human subjects (n = 10) and (iii) QMR fat and lean mass measurements compared to those obtained using the established 4‐compartment (4‐C) model method (n = 30). Results: (i) QMR represented 18 kg of oil at 40°C as 17.1 kg fat and 1 kg lean while at 30°C 15.8 kg fat and 4.7 kg lean were reported. The s.d. of repeated estimates was 0.13 kg for fat and 0.23 kg for lean mass. Adding 9 kg of water reduced the fat estimates, increased misrepresentation of fat as lean, and degraded the precision. (ii) the simulated change in the fat mass of human volunteers was accurately represented, independently of added water. (iii) compared to the 4‐C model, QMR underestimated fat and over‐estimated lean mass. The extent of difference increased with body mass. The s.d. of repeated measurements increased with adiposity, from 0.25 kg (fat) and 0.51 kg (lean) with BMI 30 kg/m2. Discussion: EchoMRI‐AH prototype showed shortcomings in absolute accuracy and specificity of fat mass measures, but detected simulated body composition change accurately and with precision roughly three times better than current best measures. This methodology should reduce the study duration and cohort number needed to evaluate anti‐obesity interventions.