Zeng Hui, Zheng Jun-Hui, Zhang Jin-E, Liu Yan-Hui, Tan Shao-Heng, Wang Guang-Yi, Liang Chang-Hong
Department of Radiology, Center of Medical Imaging, Guangdong Provincial People's Hospital, Guangzhou 510080.
Chin Med Sci J. 2006 Dec;21(4):276-80.
To distinguish the edema, injury, or rupture in the traumatic skeletal muscle fiber in vivo using diffusion tensor imaging (DTI) and tractography on magnetic resonance imaging (MRI).
The skeletal muscle trauma models were made in 4 rabbits (eight hindlimbs) by iron discus (weight 1.0 kg, diameter 6 cm) falling down vertically from 45 cm height to rabbits' thighs. Conventional sequences and two-dimensional (2D) diffusion-weighted (DW) spin-echo (SE) echo planar imaging (EPI) sequence with fat suppression (b = 600 s/mm2) were performed on 1. 5T MRI scanner. The grading of edema, injury, and fiber rupture in the damaged muscle were made according to their histopathological views, which was consistent with the images. The mean apparent diffusion coefficient (ADC) values and fractional anisotropy (FA) values were measured from the region of interests (ROIs) of all groups on 2D DW images used for tractography. Analysis of variance test was performed to analyze all data.
ADC values of the areas in normal muscle, edema muscle, injury muscle, and ruptured muscle were (6.12 +/- 1.34) x 10(-3), (6.38 +/- 1.30) x 10(-3), (8.06 +/- 0.97) x 10(-3), and (9.57 +/- 0.93) x 10(-3) mm2/s, respectively. There was significant difference among groups (P < 0.001), but no difference between edema muscle and normal muscle group (P > 0.05). The FA values of normal muscle, edema muscle, injury muscle, and ruptured muscle were 0.42 +/- 0.12, 0.36 +/- 0.12, 0.26 +/- 0.09, 0.12 +/- 0.08, respectively, with a significant difference among groups (P < 0.001). In the edema muscle, the tracking cross-fiber could be seen but it decreased slightly. In the injury muscle, the tracking fiber decreased markedly. In the ruptured muscle, the transverse-orientation tracking fiber vanished, yet some interrupted longitudinal-orientation tracking fiber could be found.
The edema, injury, and rupture of muscle fiber in rabbit damaged skeletal muscle can be verified according to the ADC and the FA on DTI and tractography.
利用磁共振成像（MRI）的扩散张量成像（DTI）和纤维束成像技术在活体中鉴别创伤性骨骼肌纤维的水肿、损伤或断裂情况。
用铁饼（重1.0kg，直径6cm）从45cm高度垂直下落撞击4只家兔（8条后肢）的大腿，制作骨骼肌创伤模型。在1.5T MRI扫描仪上进行常规序列及二维（2D）脂肪抑制扩散加权（DW）自旋回波（SE）回波平面成像（EPI）序列（b = 600 s/mm2）检查。根据损伤肌肉的组织病理学表现对水肿、损伤及纤维断裂进行分级，并与图像对照。在用于纤维束成像的2D DW图像上，测量所有组感兴趣区（ROI）的平均表观扩散系数（ADC）值和各向异性分数（FA）值。对所有数据进行方差分析。
正常肌肉、水肿肌肉、损伤肌肉及断裂肌肉区域的ADC值分别为（6.12±1.34）×10⁻³、（6.38±1.30）×10⁻³、（8.06±0.97）×10⁻³和（9.57±0.93）×10⁻³mm²/s。组间差异有统计学意义（P < 0.001），但水肿肌肉组与正常肌肉组之间无差异（P > 0.05）。正常肌肉、水肿肌肉、损伤肌肉及断裂肌肉的FA值分别为0.42±0.12、0.36±0.12、0.26±0.09、0.12±0.08，组间差异有统计学意义（P < 0.001）。在水肿肌肉中，可看到纤维束成像的交叉纤维，但略有减少。在损伤肌肉中，纤维束成像的纤维明显减少。在断裂肌肉中，横向的纤维束成像纤维消失，但可发现一些中断的纵向纤维束成像纤维。
根据DTI和纤维束成像的ADC值及FA值可验证家兔受损骨骼肌中肌肉纤维的水肿、损伤及断裂情况。
