MRI定量评估业余马拉松运动员小腿肌肉横截面积与脂肪含量的初步研究

Preliminary study on MRI quantitative assessment of calf muscle cross-sectional area and fat fraction in amateur marathon runners

目的基于T2WI-Flex脂肪抑制序列和非对称回波的最小二乘估算法迭代水脂分离方法(IDEAL-IQ)技术评估业余马拉松运动员小腿肌肉的横截面积(CSA)和脂肪分数(FF),并探讨与跑步相关指标年龄、体重指数(BMI)、跑龄、配速、月跑量的相关性。方法2022年9月至11月间于石家庄市招募业余马拉松运动员37名(马拉松组)和不常运动的健康志愿者12名(对照组)。所有受试者均行双侧小腿横断面MR扫描,序列包括T2WI-Flex脂肪抑制序列和IDEAL-IQ序列。沿肌肉轮廓边缘勾画右侧小腿前群(胫骨前肌、踇长伸肌、趾长伸肌)、小腿外群(腓骨长肌、腓骨短肌)、比目鱼肌、腓肠肌内侧头和外侧头作为感兴趣区,获得肌肉的CSA和FF值。从马拉松组中选取12名与对照组临床资料相匹配的受试者(马拉松匹配组),采用独立样本t检验或Mann-Whitney U检验比较CSA和FF的差异。采用Spearman相关分析评估37名业余马拉松运动员右小腿CSA、FF值与跑步相关指标年龄、体重指数(BMI)、跑龄、配速、月跑量指标之间的相关性。结果马拉松匹配组的右小腿比目鱼肌CSA大于对照组(t=-2.09,P=0.048);小腿其他肌群的CSA与对照组差异无统计学意义(P>0.05)。马拉松匹配组的右小腿前群、外群、比目鱼肌、腓肠肌内侧头、外侧头肌肉FF值均小于对照组(P<0.05)。37名业余马拉松运动员的BMI与右小腿前群、外群、比目鱼肌、腓肠肌内侧头、外侧头CSA和FF值呈正相关(CSA:r=0.628、0.468、0.680、0.566、0.615,P<0.05;FF值:r=0.395、0.567、0.631、0.482、0.516,P<0.05);月跑量与右小腿前群、外群、比目鱼肌、腓肠肌内侧头、外侧头FF值呈负相关(r=-0.337、-0.405、-0.437、-0.338、-0.446,P<0.05)。结论长期跑步训练可以降低小腿各个肌群的FF值,小腿肌肉FF值与月跑量呈负相关。长期跑步训练对于小腿比目鱼肌的CSA影响最大。

Objective To evaluate the calf muscle cross-sectional area(CSA)and fat fraction(FF)in amateur marathon runners based on T2WI-Flex fat-suppression sequence and iterative decomposition of water and fat with echo asymmetrical and least-squares estimation quantitation sequence(IDEAL-IQ)technique,and to explore the correlation between them and age,body mass index(BMI),running age,speed exercise,and monthly exercise.Methods From September to November 2022,37 amateur marathon group(marathon group)and 12 healthy volunteers(control group)who did not often exercise were recruited in Shijiazhuang.T2WI-Flex fat-suppression sequence and IDEAL-IQ sequence were performed on all subjects.The anterior group of the right calf(tibialis anterior,extensor hallucis longus,extensor digital longus),external group of the calf(peroneus longus,peroneus brevis),soleus,medial head and lateral head of the gastrocnemius were delineated along the edge of the muscle contour as regions of interest,and the CSA and FF values of the muscles were obtained.Twelve subjects matched with the clinical data of the control group were selected from the marathon group(marathon matched group),and the differences in CSA and FF were compared by independent sample t test or Mann-Whitney U test.Spearman correlation analysis was used to evaluate the correlation between CSA and FF values of the right calf and running-related indicators including age,BMI,running age,speed exercise,and monthly exercise in 37 amateur marathon runners.Results The CSA of the right calf soleus muscle in the marathon matched matched group was larger than that in the control group(t=-2.09,P=0.048).There was no significant difference in CSA of other calf muscles between the two groups(P>0.05).The FF values of the right calf anterior group,the outer group,the soleus muscle,the medial head and the lateral head of the gastrocnemius muscle in the marathon matched group were lower than those in the control group(P<0.05).The BMI of 37 amateur marathon runners was positively correlated with the CSA and FF values of the anterior group,the outer group,the soleus,the medial head and the lateral head of the gastrocnemius muscle(CSA:r=0.628,0.468,0.680,0.566,0.615,respectively,all P<0.05;FF value:r=0.395,0.567,0.631,0.482,0.516,respectively,all P<0.05).The FF values of the anterior group,the outer group,the soleus,the medial head and the lateral head of the gastrocnemius muscle were negatively correlated with monthly exercise(r=-0.337,-0.405,-0.437,-0.338,-0.446,respectively,all P<0.05).Conclusions Long-term running training can reduce the FF value of each calf muscle group,and the FF value of calf muscles is negatively correlated with the amount of running each month.Long-term running training has the greatest effect on the CSA of soleus muscle.