健康青年人腰背伸肌群运动前后功能MRI表现及意义

Application of blood oxygenation level dependent fMRI on lumbar dorsal extensor muscles before and after exercise in healthy young adults

目的探讨血氧水平依赖（BOLD）fMRI评估健康青年人腰背伸肌群运动前后功能改变的价值。 方法本研究为前瞻性，研究对象为30名健康青年志愿者（男15名、女15名）。对志愿者运动前后分别行BOLD-fMRI扫描，运动方式采用简易罗马凳做上半身屈伸运动。扫描所得图像进行后处理后，分别测量运动前后L3、L4椎体上缘层面左右两侧腰背伸肌群（包括多裂肌、最长肌和髂肋肌）的横截面积（CSA）和R2＊值。运动前后各肌肉间CSA、R2＊信号比较采用配对t检验（数据符合正态分布），每一肌群左右两侧CSA、R2＊信号比较采用独立样本t检验；运动前后各肌肉CSA与R2＊信相关性采用Pearson相关分析。 结果运动后L4上缘层面多裂肌、最长肌和髂肋肌R2＊值分别为（39.2±8.6）、（38.9±7.7）、（41.6±7.8）Hz，比运动前[（46.1±6.9）、（45.3±6.2）、（46.00±6.7）Hz]明显减低（t值分别为3.793、5.240、3.854，P值均〈0.01）；左右两侧各肌肉运动后R2＊值差异无统计学意义（t值分别为0.218、0.613、-0.931，P值均〉0.05）。L3上缘层面最长肌、髂肋肌运动后R2＊值分别为（44.2±9.1）、（46.6±9.3）Hz，比运动前[（48.6±7.2）、（49.7±6.8）Hz]明显减低（t值分别为2.760、2.737，P值均〈0.01），多裂肌运动后R2＊值为（43.9±9.0）Hz，与运动前（46.8±6.6）Hz比较差异无统计学意义（t=1.925，P〉0.05）；并且L3上缘层面左右两侧髂肋肌运动前后R2＊值差异有统计学意义（t=-2.476，P〈0.05）。运动后L3上缘层面右侧髂肋肌以及L4上缘层面右侧多裂肌CSA与R2＊值存在显著负相关（r分别为-0.697、-0.616，P〈0.05）。 结论BOLD-fMRI可评估腰背伸肌群运动前后功能的改变。

ObjectiveTo investigate the value of blood oxygenation level dependent （BOLD） fMRI in assessing the functional changes of the lumbar dorsal extensor muscles before and after exercise in healthy young people. MethodsThe changes of the R2＊ value of lumbar dorsal extensor group in 30 healthy young volunteers （15 males and 15 females） before and after exercise was prospectively studied. BOLD-fMRI scans were performed on healthy young volunteers before and after exercise, the exercise mode was to perform the upper body flexion and extension movement with a simple Rome stool. The scanned images were processed and analyzed, the cross-sectional area and R2＊ value of the lumbar dorsal extensor muscles （including the multifidus, the longissimus and the iliocostalis） were measured at the upper margin of the L3 and L4 vertebral body before and after exercise. The paired t test was used to compare CSA and R2＊ values of muscles before and after loading. The CSA and R2＊ value of different muscles in different sides were compared by independent sample t test. Pearson correlation analysis was used to analyze the relevance between CSA and R2＊ in muscle before and after exercise. ResultsAfter exercise, the R2＊ values of multifidus, longissimus and iliocostalis at the upper margin of the L4 vertebral body were [（39.2±8.6）,（38.9±7.7）,（41.6±7.8）]Hz, significantly lower than before exercise [（46.1±6.9）,（45.3±6.2）,（46.0±6.7）]Hz （P〈0.01）;the changes of R2＊ values of the muscles between the left and right sides before and after the movements were not statistically significant（P〉0.05）.The R2＊ values of longissimus and iliocostalis at the upper margin of the L3 vertebral body were [（44.2±9.1）, （46.6±9.3）]Hz, significantly lower than before exercise [（48.6±7.2）,（49.7±6.8）]Hz（P〈0.01）,but the R2＊ values of multifidus after loading was（43.9±9.0）Hz,there was no statistical difference compared with before exercise （46.8±6.6）Hz （P〉0.05）;there was a significant difference in the changes of R2＊ value before and after the movement between the left and right side of iliocostalis（P〈0.05）.A significant negative correlation between CSA and R2＊ value was found in the iliocostalis on the right side at the upper margin of L3 vertebral body and in the multifidus on the left side at the upper margin of L4 vertebral body, and the correlation coefficients were （-0.697,-0.616）. ConclusionBOLD-fMRI can be a new way to assess the functional changes of the lumbar dorsal extensor group before and after exercise.