Magnetic Resonance Imaging Cooling-Reheating Protocol Indicates Decreased Fat Fraction via Lipid Consumption in Suspected Brown Adipose Tissue
Magnetic Resonance Imaging Cooling-Reheating Protocol Indicates Decreased Fat Fraction via Lipid Consumption in Suspected Brown Adipose Tissue
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DOI：
10.1371/journal.pone.0126705
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发表时间：
2015-04-30
期刊：
影响因子：
3.7
通讯作者：
Kullberg, Joel
中科院分区：
文献类型：
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作者：
Lundstrom, Elin;Strand, Robin;Kullberg, Joel
ObjectivesTo评估是否可以使用水脂肪磁共振成像（MRI）冷却-再加热协议，以检测脂质含量和灌注的变化，在主要的人类棕色脂肪组织（BAT）仓库后，三个小时长的温和coldexpos.Materials和MethodsNine志愿者进行了研究，在基线时，经过三个小时长的冷暴露和随后的短期再加热后，与化学位移编码的水脂肪MRI。在半自动分割后，在颈部-锁骨上脂肪组织（被认为是疑似BAT，表示为sBAT）内量化与环境温度相关的脂肪分数（FF）和R-2* 的变化。此外，在皮下脂肪组织（不视为疑似BAT，表示为SAT）中完全自动定量FF和R-2*，以进行比较。通过假设BAT中脂质周转和灌注调节的不同时间尺度，确定这些变化是由绝对脂肪含量的改变引起的，（脂质相关）或绝对含水量改变结果冷暴露后BAT-FF降低（平均百分比变化= -1.94 pp，P = 0.021），而SAT-FF未观察到变化（平均值= 0.23 pp，P = 0.314）。冷暴露后sBAT-R-2* 和SAT-R-2 * 均呈增加趋势（均值= 0.65 s（-1），P = 0.051）和增加趋势（均值= 0.40 s（-1），P = 0.038）。sBAT-FF在再加热后仍然降低（与基线相比，平均值=-1.92pp，P = 0.008），而SAT-FF降低（与冷暴露后相比，平均值=-0.79pp，P = 0.008）。所获得的结果表明，使用冷却-再加热方案来检测颈部-锁骨上脂肪储库的变化，其是主要的人类棕色脂肪组织储库，在脂质含量和灌注方面。
ObjectivesTo evaluate whether a water-fat magnetic resonance imaging (MRI) cooling-reheating protocol could be used to detect changes in lipid content and perfusion in the main human brown adipose tissue (BAT) depot after a three-hour long mild cold exposure.Materials and MethodsNine volunteers were investigated with chemical-shift-encoded water-fat MRI at baseline, after a three-hour long cold exposure and after subsequent short reheating. Changes in fat fraction (FF) and R-2*, related to ambient temperature, were quantified within cervical-supraclavicular adipose tissue (considered as suspected BAT, denoted sBAT) after semi-automatic segmentation. In addition, FF and R-2* were quantified fully automatically in subcutaneous adipose tissue (not considered as suspected BAT, denoted SAT) for comparison. By assuming different time scales for the regulation of lipid turnover and perfusion in BAT, the changes were determined as resulting from either altered absolute fat content (lipid-related) or altered absolute water content (perfusion-related).ResultssBAT-FF decreased after cold exposure (mean change in percentage points = -1.94 pp, P = 0.021) whereas no change was observed in SAT-FF (mean = 0.23 pp, P = 0.314). sBAT-R-2* tended to increase (mean = 0.65 s(-1), P = 0.051) and SAT-R-2* increased (mean = 0.40 s(-1), P = 0.038) after cold exposure. sBAT-FF remained decreased after reheating (mean = -1.92 pp, P = 0.008, compared to baseline) whereas SAT-FF decreased (mean = -0.79 pp, P = 0.008, compared to after cold exposure).ConclusionsThe sustained low sBAT-FF after reheating suggests lipid consumption, rather than altered perfusion, as the main cause to the decreased sBAT-FF. The results obtained demonstrate the use of the cooling-reheating protocol for detecting changes in the cervical-supraclavicular fat depot, being the main human brown adipose tissue depot, in terms of lipid content and perfusion.