Branca Rosa Tamara, He Ting, Zhang Le, Floyd Carlos S, Freeman Matthew, White Christian, Burant Alex
Department of Physics and Astronomy, Biomedical Research Imaging Center, and
Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; and.
Proc Natl Acad Sci U S A. 2014 Dec 16;111(50):18001-6. doi: 10.1073/pnas.1403697111. Epub 2014 Dec 1.
The study of brown adipose tissue (BAT) in human weight regulation has been constrained by the lack of a noninvasive tool for measuring this tissue and its function in vivo. Existing imaging modalities are nonspecific and intrinsically insensitive to the less active, lipid-rich BAT of obese subjects, the target population for BAT studies. We demonstrate noninvasive imaging of BAT in mice by hyperpolarized xenon gas MRI. We detect a greater than 15-fold increase in xenon uptake by BAT during stimulation of BAT thermogenesis, which enables us to acquire background-free maps of the tissue in both lean and obese mouse phenotypes. We also demonstrate in vivo MR thermometry of BAT by hyperpolarized xenon gas. Finally, we use the linear temperature dependence of the chemical shift of xenon dissolved in adipose tissue to directly measure BAT temperature and to track thermogenic activity in vivo.
由于缺乏一种用于在体内测量棕色脂肪组织（BAT）及其功能的非侵入性工具，人类体重调节中棕色脂肪组织的研究受到了限制。现有的成像方式不具有特异性，并且对肥胖受试者中活性较低、富含脂质的BAT（BAT研究的目标人群）本质上不敏感。我们通过超极化氙气磁共振成像（MRI）展示了小鼠BAT的非侵入性成像。在刺激BAT产热过程中，我们检测到BAT对氙气的摄取增加了15倍以上，这使我们能够获取瘦型和肥胖型小鼠表型中该组织的无背景图谱。我们还通过超极化氙气展示了BAT的体内磁共振测温。最后，我们利用溶解在脂肪组织中的氙气化学位移的线性温度依赖性，直接测量BAT温度并追踪体内的产热活动。
