Comparison of brown and white adipose tissues in infants and children with chemical‐shift‐encoded water‐fat MRI

Abstract

Purpose-To compare fat-signal fractions (FFs) and T 2 * values between brown (BAT) and white (WAT) adipose tissue located within the supraclavicular fossa and subcutaneous depots, respectively.Materials and Methods-Twelve infants and 39 children were studied. Children were divided into lean and overweight/obese sub-groups. Chemical-shift-encoded water-fat MRI was used to quantify FFs and T 2 * metrics in the supraclavicular and adjacent subcutaneous adipose tissue depots. Linear regression and t-tests were performed.Results-Infants had lower supraclavicular FFs than children (p<0.01) but T 2 * values were similar (p=0.5). Lean children exhibited lower supraclavicular FFs and T 2 * values than overweight children (p<0.01). In each individual infant and child, supraclavicular FFs were consistently lower than adjacent subcutaneous FFs. Supraclavicular T 2 * values were consistently lower than subcutaneous T 2 * values in children, but not in infants. FFs in both depots were positively correlated with age and weight in infants (p<0.01). In children, they were correlated with weight and BMI (p<0.01), but not age. Correlations between T 2 * and anthropometric variables existed in children (p<0.01), but were absent in infants.Conclusion-Cross-sectional comparisons suggest variations in FF and T 2 * values in the supraclavicular and subcutaneous depots of infants and children, which are potentially indicative of physiological differences in adipose tissue fat content, amount, and metabolic activity.

Characterizing active and inactive brown adipose tissue in adult humans using PET-CT and MR imaging

“…, and subcutaneous WAT ranges from 22 to 40 s Ϫ1 (30,31). The purpose of this research was to quantify the PET-CT and MRI characteristics of active and inactive clavicular BAT in healthy adult subjects and to compare these with the values in subcutaneous WAT.…”

Magnetic Resonance Imaging of Adipose Tissue in Metabolic Dysfunction

“…This results in a lower fat fraction in BAT compared to WAT. Thus, the most commonly used MRI methods to study BAT in humans are chemical shift-encoding based fat quantification techniques [44,45]. After consideration of the aforementioned confounding factors, chemical shift encodingbased fat quantification techniques can display the PDFF [22].…”

Fat-Referenced MRI: Quanitaive MRI for Tissue Characterizaion and Volume Measurement

“…However, BAT can be depicted by either CT or MRI alone [36]. For MRI, BAT has been characterized by either water-fat imaging [37][38][39][40][41], T * 2 [38,42] or more novel approaches like Zero-Quantum Coherence [43,44]. The field is still in the early stages of mapping the true effects BAT has on the metabolism, and its association with metabolic disease.…”

“…The field is still in the early stages of mapping the true effects BAT has on the metabolism, and its association with metabolic disease. A range of smaller studies have shown metabolic associations, for instance Entringer et al observed that newborn with lower fat fraction in the supraclavicular BAT (sBAT) depot were leaner after 6 months [45], similarly Hu et al observed that sBAT was inversely associated with BMI during childhood [38], and Koksharova et al that BAT was associated with insulin sensitivity in adults [46].…”

“…There are some shifts in T 1 and T 2 of BAT water relative to the WAT water signal [37], but these contrasts may be hard to use in practice. In water-fat MRI, BAT is identified by its location and its lower fat concentration relative to WAT [37][38][39][40][41]. The main drawback of water-fat based BAT imaging is the lack of specificity, as the BAT appearing contrast could originate from combinations of WAT-LT.…”