Houchun Harry Hu1, 2, Catherine D. G. Hines3, Scott B. Reeder4
1Radiology, Children's Hospital of Los Angeles, University of Southern California, Los Angeles, CA, United States; 2Electrical Engineering, University of Southern California, Los Angeles, CA, United States; 3Merck Research Laboratories, West Point, PA, United States; 4Radiology, Medical Physics, Biomedical Engineering, and Medicine, University of Wisconsin-Madison, Madison, WI, United States
We utilized a chemical-shift water-fat MRI technique to characterize T2* and proton density fat-fraction (PDFF) differences between interscapular brown (BAT) and gonadal white (WAT) adipose tissues in lean and genetically obese mice. Lean mice (n=6) and two groups of obese ob/ob mice placed on four-week (n=6) and eight-week (n=8) diets were studied. Comparing within each group, BAT T2* and PDFFs were consistently lower than WAT (p<0.001). Comparing across groups, longer BAT T2* and greater BAT PDFFs were measured in older and more obese ob/ob mice than lean mice (p<0.001). Collectively, these observations reflect the lean groups greater BAT thermogenic activity.