Elsevier

Magnetic Resonance Imaging

Volume 58, May 2019, Pages 135-142
Magnetic Resonance Imaging

Original contribution
MRI estimates of brown adipose tissue in children – Associations to adiposity, osteocalcin, and thigh muscle volume

https://doi.org/10.1016/j.mri.2019.02.001Get rights and content
Under a Creative Commons license
open access

Highlights

  • The fat fraction of brown adipose tissue is likely negativity correlated to its potential cold-induced activity in humans.

  • This study investigates the fat fraction of brown adipose tissue in 7-year olds.

  • Positive correlations between the fat fraction and measures of adiposity were found.

  • A negative correlation to the insulin-sensitizer osteocalcin was found.

  • With correction for adiposity a negative correlation to thigh muscle volume was found.

Abstract

Context

Brown adipose tissue is of metabolic interest. The tissue is however poorly explored in children.

Methods

Sixty-three 7-year old subjects from the Swedish birth-cohort Halland Health and Growth Study were recruited. Care was taken to include both normal weight and overweight children, but the subjects were otherwise healthy. Only children born full term were included.

Water-fat separated whole-body MRI scans, anthropometric measurements, and measurements of fasting glucose and levels of energy homeostasis related hormones, including the insulin-sensitizer osteocalcin, were performed. The fat fraction (FF) and effective transverse relaxation time (T2*) of suspected brown adipose tissue in the cervical-supraclavicular-axillary fat depot (sBAT) and the FFs of abdominal visceral (VAT) and subcutaneous adipose tissue (SAT) were measured. Volumes of sBAT, abdominal VAT and SAT, and thigh muscle volumes were measured.

Results

The FF in the sBAT depot was lower than in VAT and SAT for all children. In linear correlations including sex and age as explanatory variables, sBAT FF correlated positively with all measures of adiposity (p < 0.01), except for VAT FF and weight, positively with sBAT T2* (p = 0.036), and negatively with osteocalcin (p = 0.017). When adding measures of adiposity as explanatory variables, sBAT FF also correlated negatively with thigh muscle volume (p < 0.01).

Conclusions

Whole-body water-fat MRI of children allows for measurements of sBAT. The FF of sBAT was lower than that of VAT and SAT, indicating presence of BAT. Future studies could confirm whether the observed correlations corresponds to a hormonally active BAT.

Abbreviations

BAT
brown adipose tissue
WAT
White adipose tissue
sBAT
cervical-supraclavicular-axillary fat depot
FF
fat fraction
T2*
effective transverse relaxation time
WHtR
waist-to-height ratio
VAT
visceral adipose tissue
SAT
subcutaneous adipose tissue

Keywords

Brown adipose tissue
Magnetic resonance imaging
Adiposity
Osteocalcin
Muscle volume
Quantitative MRI

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1

These authors contributed equally to this work.