UNLABELLED: Physiologic (18)F-FDG uptake in areas of supraclavicular fat in humans ("USA-Fat") has recently been recognized as (18)F-FDG uptake in apparent brown adipose tissue (BAT) using fused PET/CT technology. In this study, we evaluated (18)F-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 (18)F-FDG injections were examined under various conditions to evaluate (18)F-FDG biodistribution into interscapular BAT and major organs. In series 1, rats were given ketamine-based anesthesia or were exposed to cold (4 degrees C for 4 h) to determine whether these interventions increased (18)F-FDG uptake in BAT. In series 2, anesthetized rats (ketamine-based anesthesia) were given propranolol, reserpine, or diazepam intraperitoneally before (18)F-FDG injection to determine whether the drug reduced (18)F-FDG uptake in BAT. The control and treated groups in series 2 were also evaluated with (18)F-FDG PET/CT imaging. RESULTS: In series 1, anesthesia or exposure to cold increased (18)F-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, (18)F-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 (18)F-FDG uptake in BAT. (18)F-FDG PET/CT findings reflected these biodistribution data: The control and diazepam groups exhibited intense (18)F-FDG uptake in BAT, whereas the propranolol and reserpine groups showed only faint to mild (18)F-FDG uptake in BAT. Among several organs whose (18)F-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 (18)F-FDG uptake under stimulated conditions including exposure to cold and that propranolol or reserpine treatment can remarkably reduce the high (18)F-FDG uptake in BAT. The effect of these drugs on (18)F-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.
UNLABELLED: Physiologic (18)F-FDG uptake in areas of supraclavicular fat in humans ("USA-Fat") has recently been recognized as (18)F-FDG uptake in apparent brown adipose tissue (BAT) using fused PET/CT technology. In this study, we evaluated (18)F-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 (18)F-FDG injections were examined under various conditions to evaluate (18)F-FDG biodistribution into interscapular BAT and major organs. In series 1, rats were given ketamine-based anesthesia or were exposed to cold (4 degrees C for 4 h) to determine whether these interventions increased (18)F-FDG uptake in BAT. In series 2, anesthetized rats (ketamine-based anesthesia) were given propranolol, reserpine, or diazepam intraperitoneally before (18)F-FDG injection to determine whether the drug reduced (18)F-FDG uptake in BAT. The control and treated groups in series 2 were also evaluated with (18)F-FDG PET/CT imaging. RESULTS: In series 1, anesthesia or exposure to cold increased (18)F-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, (18)F-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 (18)F-FDG uptake in BAT. (18)F-FDG PET/CT findings reflected these biodistribution data: The control and diazepam groups exhibited intense (18)F-FDG uptake in BAT, whereas the propranolol and reserpine groups showed only faint to mild (18)F-FDG uptake in BAT. Among several organs whose (18)F-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 (18)F-FDG uptake under stimulated conditions including exposure to cold and that propranolol or reserpine treatment can remarkably reduce the high (18)F-FDG uptake in BAT. The effect of these drugs on (18)F-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.
Authors: Katherine A Zukotynski; Frederic H Fahey; Stephen Laffin; Royal Davis; S Ted Treves; Frederick D Grant; Laura A Drubach Journal: Eur J Nucl Med Mol Imaging Date: 2010-05-27 Impact factor: 9.236
Authors: Shu-fei Lin; Xiaoning Fan; Catherine Weikart Yeckel; David Weinzimmer; Tim Mulnix; Jean-Dominique Gallezot; Richard E Carson; Robert S Sherwin; Yu-Shin Ding Journal: Nucl Med Biol Date: 2012-05-16 Impact factor: 2.408
Authors: Marieke G G Sturkenboom; Otto S Hoekstra; Ernst J Postema; Josée M Zijlstra; Johannes Berkhof; Eric J F Franssen Journal: Mol Imaging Biol Date: 2009-03-27 Impact factor: 3.488
Authors: Manuel Sanchez-Alavez; Iustin V Tabarean; Olivia Osborn; Kayo Mitsukawa; Jean Schaefer; Jeffrey Dubins; Kristina H Holmberg; Izabella Klein; Joe Klaus; Luis F Gomez; Hartmuth Kolb; James Secrest; Jeanine Jochems; Kevin Myashiro; Peter Buckley; John R Hadcock; James Eberwine; Bruno Conti; Tamas Bartfai Journal: Diabetes Date: 2009-10-21 Impact factor: 9.461