Non-invasive mapping of brown adipose tissue activity with magnetic resonance imaging
Zimeng Cai, Qiaoling Zhong, Yanqiu Feng, Qian Wang, Zuoman Zhang, Cailv Wei, Zhinan Yin, Changhong Liang, Chong Wee Liew, Lawrence Kazak, Aaron M. Cypess, Zaiyi Liu, Kejia Cai
Abstract
Abstract Thermogenic brown adipose tissue (BAT) has a positive impact on whole-body metabolism. However, in vivo mapping of BAT activity typically relies on techniques involving ionizing radiation, such as [ 18 F]fluorodeoxyglucose ([ 18 F]FDG) positron emission tomography (PET) and computed tomography (CT). Here we report a noninvasive metabolic magnetic resonance imaging (MRI) approach based on creatine chemical exchange saturation transfer (Cr-CEST) contrast to assess in vivo BAT activity in rodents and humans. In male rats, a single dose of the β 3 -adrenoceptor agonist (CL 316,243) or norepinephrine, as well as cold exposure, triggered a robust elevation of the Cr-CEST MRI signal, which was consistent with the [ 18 F]FDG PET and CT data and 1 H nuclear magnetic resonance measurements of creatine concentration in BAT. We further show that Cr-CEST MRI detects cold-stimulated BAT activation in humans (both males and females) using a 3T clinical scanner, with data-matching results from [ 18 F]FDG PET and CT measurements. This study establishes Cr-CEST MRI as a promising noninvasive and radiation-free approach for in vivo mapping of BAT activity.