Intense 18F-FDG Uptake in Brown Fat Can Be Reduced Pharmacologically

Journal of Nuclear Medicine

Richard L. Wahl¹  O’Bod Nicely¹  Christian Cohade¹  Takayoshi Ishimori¹  James M. Engles¹  Mitsuaki Tatsumi¹ 

[1] Division of Nuclear Medicine, Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, Maryland Division of Nuclear Medicine, Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, Maryland Division of Nuclear Medicine, Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, Maryland

关键词: brown fat;    ¹⁸F-FDG;    rat;    PET/CT;   

DOI  :  

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

Physiologic 18F-FDG uptake in areas of supraclavicular fat in humans (“USA-Fat”) has recently been recognized as 18F-FDG uptake in apparent brown adipose tissue (BAT) using fused PET/CT technology. In this study, we evaluated 18F-FDG uptake in BAT of rats to determine whether pharmacologic or physiologic interventions affect the uptake, knowing that BAT has a high density of adrenergic innervation. Methods: Seven- to 8-wk-old female Lewis rats receiving intravenous 18F-FDG injections were examined under various conditions to evaluate 18F-FDG biodistribution into interscapular BAT and major organs. In series 1, rats were given ketamine-based anesthesia or were exposed to cold (4°C for 4 h) to determine whether these interventions increased 18F-FDG uptake in BAT. In series 2, anesthetized rats (ketamine-based anesthesia) were given propranolol, reserpine, or diazepam intraperitoneally before 18F-FDG injection to determine whether the drug reduced 18F-FDG uptake in BAT. The control and treated groups in series 2 were also evaluated with 18F-FDG PET/CT imaging. Results: In series 1, anesthesia or exposure to cold increased 18F-FDG uptake in BAT to levels 14-fold and 4.9-fold, respectively, greater than the control nonstimulated values. BAT uptake was high, comparable to that in the brain. In series 2, 18F-FDG uptake in BAT was significantly decreased to less than 30% of the control level after propranolol or reserpine (P < 0.05). Diazepam did not significantly decrease 18F-FDG uptake in BAT. 18F-FDG PET/CT findings reflected these biodistribution data: The control and diazepam groups exhibited intense 18F-FDG uptake in BAT, whereas the propranolol and reserpine groups showed only faint to mild 18F-FDG uptake in BAT. Among several organs whose 18F-FDG uptake was affected after predosing drugs, the heart exhibited considerable decreases in tracer uptake with propranolol or reserpine. Conclusion: This rodent study demonstrated that BAT can exhibit high 18F-FDG uptake under stimulated conditions including exposure to cold and that propranolol or reserpine treatment can remarkably reduce the high 18F-FDG uptake in BAT. The effect of these drugs on 18F-FDG uptake in human BAT, as well as on tracer accumulation in other organs, should carefully be evaluated clinically to minimize the USA-Fat artifact.

【 授权许可】

Unknown