Houchun Harry Hu1, 2, Daniel Larry Smith, Jr. 3, Yongbin Yang3, Guihua Zhai4, Tim R. Nagy3
1Radiology, Children's Hospital of Los Angeles, Los Angeles, CA, United States; 2Electrical Engineering, University of Southern California, Los Angeles, CA, United States; 3Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, United States; 4Radiology, University of Alabama at Birmingham, Birmingham, AL, United States
Brown adipose tissue (BAT) is involved in non-shivering thermogenesis. When stimulated, it metabolizes its fat stores to produce heat and maintain body temperature. We utilize chemical-shift MRI at 9.4T to measure BAT fat content in 3 groups of mice (n=16/group) that were singly housed at 16-cold, 23-room, and 30-warm degrees Celsius over four weeks. We demonstrate that BAT fat-signal fraction measured at week 4 is positively correlated with housing temperature (cold-50.48.0%, room-60.811.9%, hot-79.412.1%) and significantly different between groups (p<0.01). Results demonstrate the differential thermal demand of animals in each group and prove that chemical-shift MRI can reflect BAT activity in vivo.