不同年龄、性别、肌群对大腿肌肉内脂肪含量的影响

摘要

目的 评估大腿肌群的肌肉体积(muscle volume,MV)和肌肉内脂肪(intramuscular fat,IMF)含量,并探究其与年龄和性别的关系,确定评估MV和IMF的最佳层面.方法 采用飞利浦Ingenia 3.0 T MRI对50例健康志愿者进行大腿MRI检查,并分为青年组25例(年龄20~40岁)和老年组(年龄≥60岁)25例.沿着股骨长度采用3D mDixon序列进行图像采集.逐层测量MV和IMF含量,并评估年龄和性别对MV和IMF含量的影响.提出预测方程,采用单一层面在股骨不同水平评估MV和IMF.结果 与青年组比较,老年组MV明显减小(P<0.001),尤其是股四头肌;IMF含量增加(男性高于女性)(P<0.001).评估各个肌肉IMF的最佳层面大概处于其横断面最大面积处,评估整个大腿MV和IMF的最佳层面处于股骨长度的50%处.结论 采用MRI评估大腿MV和IMF具有可行性,预测方程的提出减少了分析时间.%Objective To assess the muscle volume(MV) and intramuscular fat(IMF) content in thigh muscles,and to investigate their relationships to gender and age for confirming the best representative slice for the estimation of MV and IMF content.Methods Ingenia 3.0 T MRI was used to scan the thigh in 50 healthy individuals.These subjects were divided into younger group(20-40 years old,n=25) and elderly group(≥60 years old,n=25).MRI images were acquired along the femur length using a three-dimension two-point Dixon gradient echo sequence,and the MV and IMF content were estimated from all the slices.The influences of age and gender on MV and IMF content were assessed.Predictive equations for MV and IMF content were established using a single slice at various femur levels.Results The MV decreased with age in both genders,particularly in the quadriceps femoris muscle(P<0.001).IMF content increased with age,and the increase in males was more significant than that in females(P<0.001).The optimal slice for assessing muscle was roughly situated in the largest cross section.For the entire thigh,the optimal slice for estimating MV and IMF content was obtained at 50 % femur length.Conclusion MRI is feasible for assessing MV and IMF content in the thigh,and the proposal of prediction equation reduces the analysis time.