Kinugasa Ryuta, Kawakami Yasuo, Fukunaga Tetsuo
Research Center of Sports Sciences, Musashino University, Nishitokyo, Tokyo, Japan.
J Magn Reson Imaging. 2006 Dec;24(6):1420-5. doi: 10.1002/jmri.20772.
To use muscle functional MRI (mfMRI) to compare activation levels within and among triceps surae (TS) muscles.
Seven healthy males performed five sets of 10 repetitions of a unilateral heel-raise exercise. T2-weighted images were obtained before and immediately after the exercise. Pixels that showed T2 greater than the mean +1 SD of the region of interest (ROI) in pre-exercise images and lower than the mean +1 SD of the ROI in post-exercise images were identified. The remaining T2 values in the post-exercise images were assigned to five categories indicated by color: red (highest level of activation), yellow, green, sky blue, and blue (lowest level of activation). The images were then used to construct three-dimensional (3D) images from which the volumes at each level of activation were determined.
Within each of the TS muscles the % activated volumes with low and moderate levels of activation were larger than those with a high level of activation (P < 0.05). The % activated volumes with a high level of activation were larger in the medial gastrocnemius than the soleus (Sol; P < 0.05). The Sol had a larger % activated volume with a low level of activation than the lateral gastrocnemius (P < 0.05). Each activation level was nonuniformly distributed along the length within each TS muscle.
There is substantial variation in the level of activation within and among the TS muscles; however, the activation level is mainly in the moderate to low range in all three muscles.
运用肌肉功能磁共振成像（mfMRI）比较小腿三头肌（TS）内部及之间的激活水平。
7名健康男性进行了5组，每组10次的单侧提踵运动。在运动前和运动后即刻获取T2加权图像。识别出在运动前图像中T2大于感兴趣区域（ROI）平均值+1标准差且在运动后图像中低于ROI平均值+1标准差的像素。运动后图像中的其余T2值被分为由颜色表示的五类：红色（最高激活水平）、黄色、绿色、天蓝色和蓝色（最低激活水平）。然后使用这些图像构建三维（3D）图像，从中确定每个激活水平的体积。
在每块TS肌肉内部，低激活水平和中等激活水平的激活体积百分比大于高激活水平的激活体积百分比（P < 0.05）。高激活水平的激活体积百分比在内侧腓肠肌中比在比目鱼肌中更大（P < 0.05）。比目鱼肌低激活水平的激活体积百分比大于外侧腓肠肌（P < 0.05）。每个激活水平在每块TS肌肉的长度上分布不均匀。
TS肌肉内部及之间的激活水平存在显著差异；然而，所有三块肌肉的激活水平主要处于中低范围。
