扩散张量成像在业余马拉松运动员大腿肌肉定量研究中的价值

The value of diffusion tensor imaging in the quantitative study of thigh muscles in amateur marathon runners

目的运用MR扩散张量成像(DTI)技术,定量分析静息状态下业余马拉松运动员大腿骨骼肌的微观分子水平变化。方法招募男性业余马拉松运动员30名(A组),男性健康志愿者20名(B组)。所有受试者均行双侧大腿轴面DTI扫描,应用Siemens Neuro 3D后处理软件对图像进行后处理分析,测量双侧大腿前群(股直肌、股内侧肌、股外侧肌、股中间肌)、内侧群(大收肌、长收肌)及后群(股二头肌长头、半腱肌、半膜肌)共18块肌肉的FA值及ADC值。采用独立样本t检验比较两组大腿肌肉DTI参数的差异性。结果A组大腿肌肉FA值0.20~0.30,平均(0.24±0.03),明显低于B组[FA值0.22~0.38,平均(0.27±0.03)],差异有统计学意义(t=5.164,P<0.01);A组ADC值(1.52~1.97)×10^-3mm^2/s,平均(1.74±0.10)×10^-3mm^2/s,高于B组[ADC值(1.49~1.89)×10^-3mm^2/s,平均(1.70±0.09)×10^-3mm^2/s],差异有统计学意义(t=2.060,P<0.05)。其中A组的FA值在股直肌、股内侧肌、股外侧肌、股二头肌长头、半腱肌、半膜肌中小于B组,差异有统计学意义(P<0.05);ADC值在股内侧肌、股中间肌及股二头肌长头大于B组,差异有统计学意义(P<0.05);而大腿内侧群肌肉FA值及ADC值A、B两组差异无统计学意义(P>0.05)。结论在常规MR成像无阳性发现的情况下,DTI技术能在微观分子水平早期无创地评估业余马拉松运动员静息状态下双侧大腿肌肉的细微改变,为马拉松运动引起的骨骼肌早期变化提供重要的影像证据。

Objective To test the differences in diffusion properties-namely fractional anisotropy (FA) and apparent diffusion coefficient(ADC)-between amateur marathon runners and healthy volunteers′ thigh muscles using diffusion tensor imaging (DTI) at rest. Methods Thirty amateur marathon runners(Group A) and 20 healthy volunteers (Group B) were recruited. All were males and their age was between 28 to 53 years. All subjects underwent both thigh DTI examination. DTI parameters FA and ADC were evaluated in thigh muscles(rectus femoris, vastus lateralis, vastus intermedius, vastus medialis, adductor longus, adductor magnus, biceps femoris long head, semitendinosus and semimembranosus)in all subjects. We tested the differences in diffusion properties between GroupA and B using independent sample t test. Results The average FA value of the thigh muscles measured in Group A was (0.24±0.03), which was significantly lower than that in Group B=(0.27±0.03)(t=5.164,P<0.01). The average ADC value of the thigh muscles measured in Group A was (1.74±0.10)×10^-3mm^2/s, which was significantly higher than that in Group B=(1.70±0.09)×10^-3mm^2/s (t=2.060,P<0.05). The FA value of Group A was lower than that of Group B in the rectus femoris, vastus lateralis, vastus medialis, biceps femoris long head, semitendinosus and semimembranosus (P<0.05). The ADC value of Group A was higher than that of Group B in the vastus intermedius, vastus medialis and biceps femoris long head (P<0.05). Conclusions In the absence of positive findings from conventional MRI, DTI technique can non-invasively assess the subtle changes in the bilateral thigh muscles of amateur marathon runners at rest in the early stage of microscopic molecular level, providing important imaging evidence for early changes in skeletal muscle caused by marathon.