Houchun Harry Hu1, Daniel L. Smith, Jr. 2, Tim R. Nagy2, Michael I. Goran3, Krishna S. Nayak1
1Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA; 2Department of Nutritional Sciences, University of Alabama, Birmingham, AL, USA; 3Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA
The fat-signal fraction derived from IDEAL-MRI is used to discriminate white (WAT) and brown adipose tissue (BAT) depots in mice. We found in both excised tissue samples and in vivo that WAT has a fat-signal fraction range of 90-93%. In contrast, BAT exhibits a much wider and significantly lower range of 39-62%. Analysis from high-resolution (0.6 mm isotropic) 3T results in whole juvenile and adult mice clearly identified BAT in the interscapular region, as well as perirenal and intercostal sites. We thus conclude that BAT can be non-invasively identified based on MRI measurements of IDEAL fat-signal fraction.