Fast and reproducible method for the direct quantitation of adipose tissue in newborn infants

Abstract

The role of body fat content and distribution in infants is becoming an area of increasing interest, especially as perception of its function appears to be rapidly evolving. Although a number of methods are available to estimate body fat content in adults, many are of limited use in infants, especially in the context of regional distribution and internal depots. In this study we developed and implemented a whole-body magnetic resonance imaging (MRI)-based protocol that allows fast and reproducible measurements of adipose tissue content in newborn infants, with an intra-observer variability of <2.4% and an inter-observed variability of <7%. The percentage total body fat for this cohort of infants ranged from 13.3-22.6% (mean and standard deviation: 16.6 +/- 2.9%), which agrees closely with published data. Subcutaneous fat accounted for just over 89% of the total body fat, whereas internal fat corresponded to almost 11%, most of which was nonabdominal fat. There were no gender differences in total or regional body fat content. These results show that whole-body MRI can be readily applied to the study of adipose tissue content and distribution in newborn infants. Furthermore, its noninvasive nature makes it an ideal method for longitudinal and interventional studies in newborn infants.

Adipose tissue and metabolic effects: new insight into measurements

“…The reproducibility of MRI for subcutaneous adipose tissue in the infant is between 2.4 and 4.0% and approximately 17% for visceral adipose tissue. 32 As we noted before, tissue composition may vary with age, and in neonates fat content of adipose tissue is 66% and gradually increases to 80% at the age of 13 y. 33 The most common use of MRI in body composition research is the measurement of abdominal adipose tissue distribution, and this technique is capable of distinguishing between subcutaneous and visceral adipose tissue.…”

Altered Adiposity after Extremely Preterm Birth

“…Infants underwent whole-body magnetic resonance imaging as previously described by our group (5). This was performed in natural sleep with the infant positioned supine.…”

“…We have developed the application of whole-body magnetic resonance (MR) AT imaging to newborn infants (5) and have published data on adipose distribution in a separate cohort of term infants (6). The technique is noninvasive and radiation free and enables direct quantification of individual AT compartments.…”

Distribution of Adipose Tissue in the Newborn

“…Subjects were imaged in a 1.5-T Marconi Medical System Eclipse scanner as previously described (3,7). No sedation was used and infants were positioned supine during natural sleep.…”

“…We, and others, have shown that MRI can be used in the direct assessment of adipose tissue content and distribution in neonates (2,3). The technique has been validated in animals and cadavers and can be readily used in longitudinal measurements (4 -7).…”