不同性别单侧咀嚼运动后咀嚼肌mfMRI分析

MfMRI analysis of masticatory muscles after unilateral mastication:influence of gender

目的:利用肌肉功能磁共振成像(Muscle Functional MRI,mfMRI)定量记录受试者单侧咀嚼口香糖后双侧咬肌、翼内肌、翼外肌的活动,对比不同性别受试者咀嚼肌活动后mfMRI图像T2值变化有无统计学意义。方法:选取16名(男、女各8名)健康志愿者按性别分组,分别在咀嚼口香糖前、单侧持续咀嚼5min后行咀嚼肌区轴位mfMRI扫描,观察双侧咬肌、翼内肌和翼外肌平均质子横向弛豫时间(T2)的变化,利用Image-Pro Plus6.0软件测量各咀嚼肌及相应脑脊液平均灰度值,求得咀嚼肌及相应脑脊液平均灰度值的比值,用比值进行两组间及肌肉咀嚼前后t检验,α=0.05。结果:男性组与女性组各组咀嚼肌在咀嚼口香糖前后平均灰度值比值t检验P>0.05,差异无统计学意义。咀嚼后同侧咬肌的活动最强,其次是同侧翼内肌、对侧翼外肌和对侧咬肌。结论:根据本实验结果证实了同侧咬肌、同侧翼内肌、对侧翼外肌在单侧咀嚼过程中的重要作用,而性别对单侧咀嚼后咀嚼肌T2值变化的影响没有统计学意义。

Objective： Quantitative analysis of masseter, medial pterygoid and lateral pterygoid muscles after unilateral gum chewing using muscle functional MRI （mfMRI）.To analysis whether the T2 values changes of muscles of different gender have statistical significance. Methods： 16 （8 male and 8 female） healthy volunteers were separated into two groups by sex. Every subject had two axial mfMRI scans of masticatory muscle areas before gum chewing and after 5min continuing unilateral chewing respectively to observe average proton transverse relaxation time （T2） changes of bilateral masseter, medial pterygoid and lateral pterygoid muscles. Image-Pro Plus6.0 was used to measure of the average gray values of masticatory muscles and cerebrospinal fluid. The differences between two groups and muscles before and after chewing were estimated with t-test using the ratio between average gray values of masticatory muscles and cerebrospinal fluid, α=0.05. Results： The differences of average gray value ratio of muscles in two groups before and after chewing were not statistically significant, P〉0.05. The T2 value change of the ipsilateral masseter was highest after chewing, then followed by the ipsilateral medial pterygoid, contralateral lateral pterygoid and contralateral masseter muscles. Conclusion： According to our research, the influence of gender to T2 value change ofmasticatory muscles after unilateral mastication was not statistically significant. These results affirm the importance of the ipsilateral masseter muscle, the ipsilateral medial pterygoid and contralateral lateral pterygoid muscles during unilateral mastication.