Reliability of the EchoMRI-Infant System for Water and Fat Measurements in Newborns

OBJECTIVE: The precision and accuracy of a quantitative magnetic resonance (EchoMRI-Infants™) system in newborn was determined. Methods: Canola oil and drinking water phantoms (increments of 10g to 1.9kg) were scanned four times. Instrument reproducibility was assessed from 3 scans (within 10-minutes) in 42 healthy term newborns (12–70 hours post-birth). Instrument precision was determined from the coefficient of variation (CV) of repeated scans for total water, lean, and fat measures for newborns and the mean difference between weight and measurement for phantoms. In newborns, the system accuracy for total body water (TBW) was tested against deuterium dilution (D(2)O). RESULTS: In phantoms, the repeatability and accuracy of fat and water measurements increased as the weight of oil and water increased. TBW was overestimated in amounts >200g. In newborns weighing 3.14kg, fat, lean and TBW were 0.52kg (16.48%), 2.28kg and 2.40kg, respectively. EchoMRI’s reproducibility (CV) was 3.27%, 1.83% and 1.34% for total body fat, lean, and TBW, respectively. EchoMRI-TBW values did not differ from D(2)O; mean difference − 1.95±6.76%, p=0.387; mean bias (limits of agreement) 0.046 kg (−0.30 to 0.39 kg). CONCLUSIONS: EchoMRI infant system’s precision and accuracy for total body fat and lean are better than established techniques and equivalent to D(2)O for TBW in phantoms and newborns.