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 [¹⁸F]fluorodeoxyglucose ([¹⁸F]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 β₃-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 [¹⁸F]FDG PET and CT data and ¹H 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 [¹⁸F]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.

产热棕色脂肪组织（BAT）对全身代谢有积极影响。然而，BAT 活性的体内绘图通常依赖于涉及电离辐射的技术，例如[ ¹⁸ F]氟脱氧葡萄糖（[ ¹⁸ F]FDG）正电子发射断层扫描（PET）和计算机断层扫描（CT）。在此，我们报告了一种基于肌酸化学交换饱和转移 (Cr-CEST) 对比的无创代谢磁共振成像 (MRI) 方法，用于评估啮齿动物和人类体内 BAT 活性。在雄性大鼠中，单剂量的 β ₃ -肾上腺素受体激动剂 (CL 316,243) 或去甲肾上腺素以及冷暴露会引发 Cr-CEST MRI 信号的强烈升高，这与 [ ¹⁸ F]FDG PET 一致BAT 中肌酸浓度的 CT 数据和¹ H 核磁共振测量结果。我们进一步表明，Cr-CEST MRI 使用 3T 临床扫描仪检测人类（男性和女性）冷刺激的 BAT 激活，并与 [ ¹⁸ F]FDG PET 和 CT 测量的数据匹配结果。这项研究将 Cr-CEST MRI 确立为一种有前景的无创、无辐射体内 BAT 活性测绘方法。