Richard Gabriel, Noll Christophe, Archambault Mélanie, Lebel Réjean, Tremblay Luc, Ait-Mohand Samia, Guérin Brigitte, Blondin Denis P, Carpentier André C, Lepage Martin
Sherbrooke Molecular Imaging Center, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, Quebec, Canada.
Division of Endocrinology, Department of Medicine, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Quebec, Canada.
Magn Reson Med. 2021 Mar;85(3):1625-1642. doi: 10.1002/mrm.28535. Epub 2020 Oct 3.
Determine if dynamic contrast enhanced (DCE) -MRI and/or 68 gallium 1,4,7,10-tetraazacyclododecane N, N', N″, N‴-tretraacetic acid ( Ga-DOTA) positron emission tomography (PET) can assess perfusion in rat brown adipose tissue (BAT). Evaluate changes in perfusion between cold-stimulated and heat-inhibited BAT. Determine if the C-acetate pharmacokinetic model can be constrained with perfusion information to improve assessment of BAT oxidative metabolism.
Rats were split into three groups. In group 1 (N = 6), DCE-MRI with gadobutrol was compared directly to Ga-DOTA PET following exposure to 10 °C for 48 h. C-Acetate PET was also performed to assess oxidation. In group 2 (N = 4), only Ga-DOTA PET was acquired following exposure to 10 °C for 48 h. Finally, in group 3 (N = 10), perfusion was assessed with DCE-MRI in rats exposed to 10 °C or 30 °C for 48 h, and oxidation was measured with C-acetate. Perfusion was quantified with a two-compartment pharmacokinetic model, while oxidation was assessed by a four-compartment model.
DCE-MRI and Ga-DOTA PET provided similar perfusion measures, but a decrease in the perfusion signal was noted with longer imaging sessions. Exposure to 10 °C or 30 °C did not affect the perfusion measures, but the C-acetate signal increased in BAT at 10 °C. Without prior information about blood volume, the C-acetate compartment model overestimated blood volume and underestimated oxidation in 10 °C BAT.
Precise assessment of oxidation via C-acetate PET requires prior information about blood volume which can be obtained by DCE-MRI or Ga-DOTA PET. Since perfusion can change rapidly, simultaneous PET-MRI would be preferred.
确定动态对比增强（DCE）-磁共振成像（MRI）和/或68镓-1,4,7,10-四氮杂环十二烷-N,N',N″,N‴-四乙酸（Ga-DOTA）正电子发射断层扫描（PET）能否评估大鼠棕色脂肪组织（BAT）的灌注情况。评估冷刺激和热抑制的BAT之间灌注的变化。确定碳-11乙酸盐药代动力学模型是否可以通过灌注信息进行约束，以改善对BAT氧化代谢的评估。
将大鼠分为三组。在第1组（N = 6）中，在暴露于10°C 48小时后，将使用钆布醇的DCE-MRI与Ga-DOTA PET直接进行比较。还进行了碳-11乙酸盐PET以评估氧化情况。在第2组（N = 4）中，仅在暴露于10°C 48小时后采集Ga-DOTA PET。最后，在第3组（N = 10）中，对暴露于10°C或30°C 48小时的大鼠用DCE-MRI评估灌注情况，并用碳-11乙酸盐测量氧化情况。用双室药代动力学模型对灌注进行定量，而用四室模型评估氧化情况。
DCE-MRI和Ga-DOTA PET提供了相似的灌注测量值，但随着成像时间延长，灌注信号有所下降。暴露于10°C或30°C不影响灌注测量值，但在10°C时BAT中的碳-11乙酸盐信号增加。在没有血容量的先验信息的情况下，碳-11乙酸盐隔室模型高估了10°C BAT中的血容量并低估了氧化情况。
通过碳-11乙酸盐PET精确评估氧化需要血容量的先验信息，这可以通过DCE-MRI或Ga-DOTA PET获得。由于灌注变化迅速，PET-MRI同步检查更为可取。
