Identification of brown adipose tissue in mice with fat–water IDEAL‐MRI

Journal of Magnetic Resonance Imaging (Impact Factor: 2.79). 05/2010; 31(5):1195 - 1202. DOI: 10.1002/jmri.22162

ABSTRACT Purpose:To investigate the feasibility of using IDEAL (Iterative Decomposition with Echo Asymmetry and Least squares estimation) fat–water imaging and the resultant fat fraction metric in detecting brown adipose tissue (BAT) in mice, and in differentiating BAT from white adipose tissue (WAT).Materials and Methods:Excised WAT and BAT samples and whole-mice carcasses were imaged with a rapid three-dimensional fat–water IDEAL-SPGR sequence on a 3 Tesla scanner using a single-channel wrist coil. An isotropic voxel size of 0.6 mm was used. Excised samples were also scanned with single-voxel proton spectroscopy. Fat fraction images from IDEAL were reconstructed online using research software, and regions of WAT and BAT were quantified.Results:A broad fat fraction range for BAT was observed (40–80%), in comparison to a tighter and higher WAT range of 90–93%, in both excised tissue samples and in situ. Using the fat fraction metric, the interscapular BAT depot in each carcass could be clearly identified, as well as peri-renal and inguinal depots that exhibited a mixed BAT and WAT phenotype appearance.Conclusion:Due to BAT's multi-locular fat distribution and extensive mitochondrial, cytoplasm, and vascular supply, its fat content is significantly less than that of WAT. We have demonstrated that the fat fraction metric from IDEAL-MRI is a sensitive and quantitative approach to noninvasively characterize BAT. J. Magn. Reson. Imaging 2010;31:1195–1202. © 2010 Wiley-Liss, Inc.

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Available from: Tim R Nagy, Aug 14, 2015
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    • "ering thermogenesis in the mutants because the mdm mutation a↵ects muscle. However, we can- 207 not rule out the possibility of di↵erences in nonshivering thermogenesis in brown adipose tissue 208 (Loncˇar, 1991; Klaus et al., 1998; Hu et al., 2010). While distinguishing between the importance 209 of muscle-driven shivering thermogenesis, brown adipose-based nonshivering thermogenesis, and 210 heat produced through other metabolic pathways is dicult, it is clear that the mice are heterother- 211 mic because heat production is quickly surpassed by heat loss. "
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    Journal of Experimental Biology 01/2015; 218(5). DOI:10.1242/jeb.111849 · 3.00 Impact Factor
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    • "The feasibility of using magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) for BAT detection is discussed elsewhere (Hu and Gilsanz, 2011). Of particular note, the distinction of BAT from WAT has been achieved based on their relative fat contents, which produce different signal patterns in chemicalshift–water–fat separation MRI (Hu et al., 2010a,b). Additionally, BAT and WAT were also shown to appear in non-overlapping regions in the HU scale (BAT displaying greater attenuation due to its higher vascularization and water content), even though both tissues are HU-negative and therefore distinguishable from bone and all other HU-positive soft tissues (Hu et al., 2011). "
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