MRI characterization of brown adipose tissue under thermal challenges in normal weight, overweight, and obese young men.
MRI characterization of brown adipose tissue under thermal challenges in normal weight, overweight, and obese young men.
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DOI：
10.1002/jmri.25836
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发表时间：
2018-04
期刊：
影响因子：
--
通讯作者：
Landsberg L
中科院分区：
文献类型：
--
作者：
Deng J;Neff LM;Rubert NC;Zhang B;Shore RM;Samet JD;Nelson PC;Landsberg L
棕色脂肪组织（BAT）在人体中的存在及其在人体代谢中的潜在作用最近已被认识到。18F-FDG PET/CT是目前检测轻度冷暴露后代谢活性BAT中葡萄糖摄取的标准成像方法。MRI已越来越多地用于BAT的表征。目的是在正常体重、超重和肥胖受试者中实施非活动和冷激活状态下BAT表征的定量狄克逊MRI方法。假设BAT的MRI特征将区分非肥胖和肥胖受试者，并且通过MRI检测到的响应于热挑战的BAT激活将与通过PET/CT测量的BAT活性相关。这是一项针对人类受试者的前瞻性研究。15名男性受试者（20.7 ± 1.5岁），包括6名正常体重、5名超重和4名肥胖受试者参加了研究。多回波狄克逊MRI序列在1.5特斯拉扫描仪上进行。在热中性、非颤抖产热和随后的预热条件下采集MR成像。脂肪分数（FF），R2* 和双键（ndb）的数量进行了测量，通过解决一个优化问题，适合同相和异相MR信号强度的脂肪-水干扰模型。由两名MRI物理学家进行成像采集和后处理。在每例受试者中，计算每种热条件下所有BAT ROI内每个体素的FF、R2* 和ndb的狄克逊MRI测量值。使用双样本t检验比较非肥胖（即正常体重/超重）和肥胖受试者之间的平均FF、R2* 和ndb。进行受试者工作特征（ROC）分析以区分非肥胖与肥胖受试者。使用Pearson相关性将响应于热条件变化的BAT MRI测量变化与通过PET/CT测量的高代谢BAT体积/活性进行比较。此外，BAT MRI测量结果与使用皮尔逊相关性的身体肥胖进行了比较。p值（P）< 0.05被认为具有统计学显著性。肥胖者在三种热环境下的FF值均高于非肥胖者，而R2* 值低于非肥胖者（P < 0.01）。ROC分析表明，FF和R2* 是区分非肥胖和肥胖受试者的极好预测因子（100%特异性和100%灵敏度）。通过PET/CT测量，热挑战下的FF变化与高代谢BAT体积（激活期间r =-0.55，P = 0.04，失活期间r = 0.72，P = 0.003）和BAT活性（失活期间r = 0.69，P = 0.006）相关。三种热条件下的FF和R2* 与体脂肪率高度相关（P ≤ 0.002）。BAT的MRI特征在非肥胖和肥胖受试者之间区分为失活和激活状态。通过狄克逊MRI检测到的BAT对热刺激的反应与代谢活性BAT的葡萄糖摄取相关。
The presence of brown adipose tissue (BAT) in humans and its potential role in human metabolism have been recently recognized. 18F-FDG PET/CT is the current standard imaging method to detect glucose uptake in metabolically active BAT after mild cold exposure. MRI has increasingly been exploited in characterization of BAT. The purpose is to implement quantitative Dixon MRI methods for BAT characterization at inactive and cold-activated states in normal weight, overweight, and obese subjects. The hypotheses are that MRI characteristics of BAT would differentiate between non-obese and obese subjects, and activation of BAT in response to thermal challenges that are detected by MRI would be correlated with BAT activity measured by PET/CT. This is a prospective study on human subjects. Fifteen male subjects (20.7 ± 1.5 years old) including 6 normal weight, 5 overweight and 4 obese subjects participated the study. Multi-echo Dixon MRI sequence was performed on a 1.5 Tesla scanner. MR Imaging was acquired under thermoneutral, non-shivering thermogenesis and subsequent warm up conditions. Fat fraction (FF), R2* and the number of double bonds (ndb) were measured by solving an optimization problem that fits in- and out-of-phase MR signal intensities to the fat-water interference models. Imaging acquisition and post-processing were performed by two MRI physicists. In each subject, Dixon MRI measurements of FF, R2* and ndb were calculated for each voxel within all BAT ROIs under each thermal condition. Mean FF, R2* and ndb were compared between non-obese (i.e. normal weight/overweight) and obese subjects using the two sample t-test. Receiver operating characteristic (ROC) analyses were performed to differentiate non-obese vs. obese subjects. BAT MRI measurement changes in response to thermal condition changes were compared with hypermetabolic BAT volume/activity measured by PET/CT using the Pearson’s correlation. In addition, BAT MRI measurements were compared with body adiposity using the Pearson’s correlation. A p-value (P) < 0.05 was considered statistically significant. Obese subjects showed higher FF and lower R2* than non-obese subjects under all three thermal conditions (P < 0.01). ROC analyses demonstrated that FF and R2* were excellent predictors for the differentiation of non-obese from obese subjects (100% specificity and 100% sensitivity). FF changes under thermal challenges were correlated with hypermetabolic BAT volume (r = −0.55, P = 0.04 during activation, and r = 0.72, P = 0.003 during deactivation), and with BAT activity (r = 0.69, P = 0.006 during deactivation), as measured by PET/CT. FF and R2* under all three thermal conditions were highly correlated with body adiposity (P ≤ 0.002). MRI characteristics of BAT differentiated between non-obese and obese subjects in both inactivated and activated states. BAT activation detected by Dixon MRI in response to thermal challenges were correlated with glucose uptake of metabolically active BAT.
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影响因子：
4.9
作者：
Hibi, M.;Oishi, S.;Matsushita, M.;Yoneshiro, T.;Yamaguchi, T.;Usui, C.;Yasunaga, K.;Katsuragi, Y.;Kubota, K.;Tanaka, S.;Saito, M.
通讯作者：
Saito, M.
影响因子：
18.2
作者：
Kajimura S;Saito M
通讯作者：
Saito M
影响因子：
3.7
作者：
Lundstrom, Elin;Strand, Robin;Kullberg, Joel
通讯作者：
Kullberg, Joel
影响因子：
3.3
作者：
Hernando, D.;Haldar, J. P.;Liang, Z. -P.
通讯作者：
Liang, Z. -P.
影响因子：
3.3
作者：
Hernando, Diego;Kellman, P.;Haldar, J. P.;Liang, Z-P.
通讯作者：
Liang, Z-P.