Evaluation Of The Changes Of The Paraspinal Muscles Before And After Exercise Using The Magnetic Resonance Imaging

Objective : Through the study of functional magnetic resonance imaging (fMRI),including BOLD and T2-mapping, of the lumbar extensor muscles(multifidus?longissimus and iliocostalis) before and after exercise in healthy volunteers, to observe the changes of R2* value and T2 value of the lumbar extensor muscles before and after exercise and investigate the characteristics of fMRI signal changes of lumbar extensor muscles before and after loading.Methods: In this study, 30 healthy volunteers were selected, including 15 man and 15 woman. The age ranged from 19 to 30 years, with an average age of (24.81 + 2.29)years old. BOLD and T2-mapping scans were performed before and after exercise w:ith MRI scanner (PHILIPS Achieva 3.0T Tx). The R2* value and T2 value of the lumbar extensor muscles were collected, before and after loading. The movement is to do upper body flexion and extension movement using simple Rome stool. To ensure that the quality of action and the number of actions consistent, the whole process of movement has been guided by professional person. All the images have been processed on GE advantage windows 4.4 workstation. T2 value.R2*value and CSA of all muscles at L3 and L4 upper edge of vertebral body has been measured and BOLD.T2-mapping pcolor has been reconstructed on the workstation. SPSS22.0 statistical software was used to analyze all the data.Results: The CSA of the lumbar extensor muscles increased with the BMI, and the total CSA of male muscle is bigger than that of female (P < 0.001). On the upper edge of L3 and L4 the CSA of each muscle increased significantly after loading (P< 0.001). The changes of CSA of multifidus in the upper edge of L3 were smaller than those of other muscles (P < 0.05). There was significant difference in the CSA changes in female group between the left and right sides of the iliocostalis after exercise (P < 0.05), but there was no significant difference in male group.The R2* values of muscles were decreased after exercise, but on the upper edge of L3, the R2* values of multifidus has no significant difference before and after exercise(P=0.064). There was significant difference in the changes of R2*value, on the upper edge of L3, in female group between the left and right sides of the iliocostalis after exercise (P < 0.05),but the difference is not existence in male group.The T2 values of muscles were increased after exercise(P < 0.001), among them, on the upper edge of L3, the change of T2 value of multifidus between the left and right sides were significant difference(P > 0.05), but the difference is not existence in other muscles.Conclusions : On the upper edge of L3 and L4, the T2 values, CSA of muscles were increased and the R2* values decreased after loading. But the changes of CSA and R2* values of multifidus on the upper edge of L3 are smaller than other muscles. In female group, at the same level of L3 upper edge, the changes of CSA and R2a* values of iliocostalis between the left and right sides were obviously different.