Validation of Quantitative Magnetic Resonance Body Composition Analysis for Infants Using Piglet Model

Abstract

ABSTRACT:A study was conducted to validate the use of a quantitative magnetic resonance (QMR) device for measuring the body composition of infants and neonates weighing Ͻ12 kg using the pig as a model. A total of 25 piglets weighing between 2 and 12 kg were studied. Body composition was assessed by QMR, dual-energy x-ray absorptiometry (DXA), and whole-body chemical analysis (CA) of carcass for lipid and water content. The precision, mean and SD of repeated measurements, of QMR to estimate fat mass (FM), lean mass (LM), and total body water (TBW) for five consecutive scans with reposition was 12.5, 32.0, and 36.0 g, respectively. QMR measures of FM, LM, and TBW were highly and significantly correlated with CA of carcass. In terms of accuracy, mean difference between QMR and CA (percent of mean value for CA), QMR overestimated FM by 40 g (4.7%), overestimated LM by 114.9 g (2.1%), and underestimated TBW by 134.6 g (3.1%). This study concludes that QMR provides precise and accurate measures of FM, LM, and TBW in piglet weighing up to 12 kg. These results suggest that QMR can provide valuable body composition data in longitudinal studies in infants. A ccurate assessment and tracking of infant body composition is useful in evaluating the amount and quality of weight gain, which can provide key information in both clinical and research settings. Body composition analysis (BCA) can be used to monitor and evaluate infant growth patterns, efficacy of nutritional and medical interventions, progression of chronic disease, and recovery from malnutrition (1-5).A large variety of nondestructive BCA methods have been developed, each with its advantages and shortcomings, such as air-displacement plethysmography (ADP) (6), bioelectrical impedance analysis (BIA) (7), dual-energy x-ray absorptiometry (DXA) (8), total-body electrical conductivity (TOBEC) (9), total body potassium (TBK) (10), isotope dilution (11), skin-fold thickness measurements (SFT) (12), multicompartment models (13), computed tomography (CT) (14), MRI (15), magnetic resonance spectroscopy (MRS) (16), and quantitative magnetic resonance (QMR) (17).Common shortcomings include complexity and time needed to obtain results (multicomponent models, TBK, isotope dilution, MRI, and MRS), immobilization requirement (MRI, MRS, CT, and DXA), expensive equipment (MRI, MRS, CT, DXA, QMR, and TOBEC), reliability and correspondence of relations between measured quantities and body components (BIA, TOBEC, ADP, and SFT), radiation exposure (CT and DXA), and potential vulnerability to oversimplification (ADP and SFT).QMR devices stand out in that they are fast and very easy to use, require no sedation or anesthesia, and are free of radiation, while capable of unsurpassed precision and high accuracy. Typical scan times range from Ͻ1 min to Ͻ4 min in different specific devices and applications, and less than half an hour of training is sufficient for a typical user.The QMR method is a branch of nuclear magnetic resonance (NMR), for whole body measurement of fat, lean tissues, free...

In VivoDetermination of Body Composition in Zebrafish (Danio rerio) by Quantitative Magnetic Resonance

“…FM estimates ranged from 0.007 to 0.036 g, while lean mass ranged from 0.065 to 0.243 g. When validating in vivo methods of body composition analysis, the precision for FM is often less than that for FFM. 7,8,20 CV is a function of body mass such that with a fixed measurement error or uncertainty, there is more variance with a smaller body compartment mass compared with larger body composition compartment masses. 8,20 Therefore, the smaller amounts of FM present compared to FFM in the current study may contribute to differences in precision between the body compartments.…”

“…7,8,20 CV is a function of body mass such that with a fixed measurement error or uncertainty, there is more variance with a smaller body compartment mass compared with larger body composition compartment masses. 8,20 Therefore, the smaller amounts of FM present compared to FFM in the current study may contribute to differences in precision between the body compartments. However, it should also follow that as FM increases in the fish, QMR measurements for that component will be more precise.…”

Air-displacement plethysmography for determining body composition in neonates: validation using live piglets

“…Piglets have been used earlier to validate several techniques that are relevant for neonatal care (17)(18)(19), and are considered relevant models for the study of human nutrition (13,20). The %FM for a piglet is only 1% at birth, which corresponds to the %FM of a preterm human infant with a gestational age of 30 wk.…”

“…In addition, the radiation associated with the measurement precludes the performance of multiple DXA scans for the monitoring of infant growth (5). Quantitative nuclear magnetic resonance was found to be accurate, based on a comparison with biochemical analysis in pigs, and was precise for body weights between 3 and 50 kg (R 2 = 0.87) (19). Although quantitative nuclear magnetic resonance is a quick and noninvasive technique just as ADP is, ADP has the additional advantage of being feasible in neonatal intensive care units because of the relatively small size and better mobility of the instrument and the shorter duration required to carry out the measurements.…”

“…Anthropometry was found to lack accuracy (4). A comparison of the measurement of %FFM and %FM using DXA and biochemical analysis found DXA to be accurate for the determination of %FFM but not for %FM (R 2 = 0.36), with a 15% overestimation in the latter (19). In addition, the radiation associated with the measurement precludes the performance of multiple DXA scans for the monitoring of infant growth (5).…”