U Din Mueez, Raiko Juho, Saari Teemu, Saunavaara Virva, Kudomi Nobu, Solin Olof, Parkkola Riitta, Nuutila Pirjo, Virtanen Kirsi A
Turku PET Centre, Turku University Hospital, 20520 Turku, Finland.
Turku PET Centre, University of Turku, 20520 Turku, Finland.
J Clin Endocrinol Metab. 2017 Jul 1;102(7):2258-2267. doi: 10.1210/jc.2016-2698.
Metabolic imaging studying brown adipose tissue (BAT) physiology has increased, in which computed tomography (CT) is commonly used as an anatomical reference for metabolic positron emission tomography (PET) imaging. However, the capacity of CT to provide metabolic information has been underexploited.
To evaluate whether CT radiodensity of BAT could noninvasively estimate underlying tissue morphology, regarding amount of stored triglycerides. Furthermore, could the alteration in tissue characteristics due to cold stimulus, as a marker for active BAT, be detected with radiodensity? Can BAT be differentiated from white adipose tissue (WAT) solely using CT-based measurements?
DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional study evaluating 66 healthy human subjects with CT, PET, and 1H-magnetic resonance spectroscopy (1H-MRS).
BAT radiodensity was measured with CT. BAT-stored triglyceride content was measured with 1H-MRS. Arterial blood volume in BAT, as a marker of tissue vascularity, was measured with [15O]H2O, along with glucose or fatty acid uptake using [18F]2-fluoro-2-deoxy-D-glucose or 14(R,S)-[18F]fluoro-6-thia-heptadecanoic acid PET imaging, respectively.
BAT radiodensity was found to be correlating with tissue-retained blood and triglyceride content. Cold stimulus induced an increase in BAT radiodensity. Active BAT depots had higher radiodensity than both nonactive BAT and WAT. BAT radiodensity associated with systemic metabolic health parameters.
BAT radiodensity can be used as a marker of underlying tissue morphology. Active BAT can be identified using CT, exploiting tissue composition information. Moreover, BAT radiodensity provides an insight into whole-body systemic metabolic health.
研究棕色脂肪组织（BAT）生理学的代谢成像有所增加，其中计算机断层扫描（CT）通常用作代谢正电子发射断层扫描（PET）成像的解剖学参考。然而，CT提供代谢信息的能力尚未得到充分利用。
评估BAT的CT放射密度是否能够无创地估计潜在的组织形态，即储存的甘油三酯量。此外，作为活跃BAT标记的冷刺激引起的组织特征变化能否通过放射密度检测到？仅使用基于CT的测量能否将BAT与白色脂肪组织（WAT）区分开来？
设计、设置和参与者：一项横断面研究，对66名健康人类受试者进行CT、PET和1H磁共振波谱（1H-MRS）检查。
用CT测量BAT放射密度。用1H-MRS测量BAT储存的甘油三酯含量。用[15O]H2O测量BAT中的动脉血容量作为组织血管化的标记，同时分别使用[18F]2-氟-2-脱氧-D-葡萄糖或14（R，S）-[18F]氟-6-硫十七烷酸PET成像测量葡萄糖或脂肪酸摄取。
发现BAT放射密度与组织保留的血液和甘油三酯含量相关。冷刺激导致BAT放射密度增加。活跃的BAT储存部位的放射密度高于非活跃的BAT和WAT。BAT放射密度与全身代谢健康参数相关。
BAT放射密度可作为潜在组织形态的标记。利用组织成分信息，通过CT可以识别活跃的BAT。此外，BAT放射密度有助于了解全身系统代谢健康状况。
