Imaging Brown Adipose Tissue: Current State and Future Perspective

Brown adipose tissue (BAT) is a specialized type of fat tissue that utilizes various nutrients and is considered a novel therapeutic target for metabolic, disorders, cardiovascular diseases, and certain types of cancer. However, the current standard imaging method for BAT, ¹⁸F-flurodeoxyglucose positron emission tomography computed tomography ([¹⁸F] FDG PET-CT), fails to meet clinical demands due to its prohibitive costs, prolonged imaging times, and radiation exposure, which are significant concerns for longitudinal studies. To overcome these limitations, emerging imaging modalities are being explored, aiming to address these challenges by focusing on alternative biomarkers of BAT, such as lipid content, perfusion, density, thermal emissions, and mitochondrial activity. Advanced imaging methods have been developed for precise imaging, facile operation, and broad applicability. In this review, we provide a brief overview of BAT physiology and function, as well as current advancements in BAT imaging methods, including positron emission tomography, single photon emission computed tomography, magnetic resonance imaging, computed tomography, infrared thermography, optoacoustic imaging, and Xenon-enhanced imaging. Future perspectives, such as the application of artificial intelligence to BAT imaging, are also discussed.