Grimm A, Meyer H, Nickel M D, Nittka M, Raithel E, Chaudry O, Friedberger A, Uder M, Kemmler W, Engelke K, Quick H H
Alexandra Grimm, Institute of Medical Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Henkestr. 91, 91052 Erlangen, Germany, E-mail address:
J Frailty Aging. 2019;8(1):21-26. doi: 10.14283/jfa.2018.16.
Changes in muscle fat composition as for example observed in sarcopenia, affect physical performance and muscular function, like strength and power.
The purpose of this study was to compare 6-point Dixon magnetic resonance imaging and multi-echo magnetic resonance spectroscopy sequences to quantify muscle fat. Setting, participants and measurements: Two groups were recruited (G1: 23 healthy young men (28 ± 4 years), G2: 56 men with sarcopenia (80 ± 5 years)). Proton density fat fraction was measured with a 6-point product and a 6-point prototype Dixon sequence in the left thigh muscle and with a high-speed multi-echo T2*-corrected H1 magnetic resonance spectroscopy sequence within the semitendinosus muscle of the left thigh. To evaluate the comparability among the different methods, Bland-Altman and linear regression analyses of the proton density fat fraction results were performed.
Mean differences ± 1.96 * standard deviation between spectroscopy and 6pt Dixon sequences were 1.9 ± 3.3% and 1.5 ± 3.6% for the product and prototype sequences, respectively. High correlations were measured between the proton density fat fraction results of the 6-point Dixon sequences and spectroscopy (R = 0.95 for the product sequence and R = 0.97 for the prototype sequence).
Dixon imaging and spectroscopy sequences show comparable accuracy for fat measurements in the thigh. Spectroscopy is a local measurement, whereas Dixon sequences provide maps of the fat distribution. The high correlations of the 6-point Dixon sequences with spectroscopy support their clinical use. They provide higher spatial resolution than spectroscopy, but are not suitable for a more complicated spectral analysis to separate extra- and intramyocellular lipids.
肌肉脂肪组成的变化，如在肌肉减少症中观察到的那样，会影响身体性能和肌肉功能，如力量和功率。
本研究的目的是比较6点 Dixon磁共振成像和多回波磁共振波谱序列以量化肌肉脂肪。设置、参与者和测量：招募了两组（G1：23名健康年轻男性（28±4岁），G2：56名患有肌肉减少症的男性（80±5岁））。使用6点乘积和6点原型 Dixon序列测量左大腿肌肉的质子密度脂肪分数，并使用高速多回波T2*校正的H1磁共振波谱序列测量左大腿半腱肌内的质子密度脂肪分数。为了评估不同方法之间的可比性，对质子密度脂肪分数结果进行了Bland-Altman分析和线性回归分析。
对于乘积序列和原型序列，波谱与6点 Dixon序列之间的平均差异±1.96×标准差分别为1.9±3.3%和1.5±3.6%。6点 Dixon序列和波谱的质子密度脂肪分数结果之间具有高度相关性（乘积序列R = 0.95，原型序列R = 0.97）。
Dixon成像和波谱序列在测量大腿脂肪方面显示出相当的准确性。波谱是局部测量，而Dixon序列提供脂肪分布图。6点 Dixon序列与波谱的高度相关性支持其临床应用。它们提供比波谱更高的空间分辨率，但不适用于更复杂的光谱分析以分离细胞外和细胞内脂质。
