Charité Universitätsmedizin Berlin, Center for Muscle and Bone Research, Hindenburgdamm 30, Berlin, Germany.
Physiol Meas. 2011 Jan;32(1):35-50. doi: 10.1088/0967-3334/32/1/003. Epub 2010 Nov 19.
Muscle size in the lower limb is commonly assessed in neuromuscular research as it correlates with muscle function and some approaches have been assessed for their ability to provide valid estimates of muscle volume. Work to date has not examined the ability of different measurement approaches (such as cross-sectional area (CSA) measures on magnetic resonance (MR) imaging) to accurately track changes in muscle volume as a result of an intervention, such as exercise, injury or disuse. Here we assess whether (a) the percentage change in muscle CSA in 17 lower-limb muscles during 56 days bed-rest, as assessed by five different algorithms, lies within 0.5% of the muscle volume change and (b) the variability of the outcome measure is comparable to that of muscle volume. We find that an approach selecting the MR image with the highest muscle CSA and then a series of CSA measures, the number of which depended upon the muscle considered, immediately distal and proximal, provided an acceptable estimate of the muscle volume change. In the vastii, peroneal, sartorius and anterior tibial muscle groups, accurate results can be attained by increasing the spacing between CSA measures, thus reducing the total number of MR images and hence the measurement time. In the two heads of biceps femoris, semimembranosus and gracilis, it is not possible to reduce the number of CSA measures and the entire muscle volume must be evaluated. Using these approaches one can reduce the number of CSA measures required to estimate changes in muscle volume by ~60%. These findings help to attain more efficient means to track muscle volume changes in interventional studies.
下肢肌肉大小通常在神经肌肉研究中进行评估，因为它与肌肉功能相关，并且已经评估了一些方法来评估它们提供肌肉体积准确估计的能力。迄今为止的工作尚未检查不同测量方法（例如磁共振成像（MR）上的横截面积（CSA）测量）是否能够准确跟踪由于干预（如运动，损伤或失用）引起的肌肉体积变化。在这里，我们评估了以下两种情况：（a）通过五种不同算法评估的 56 天卧床休息期间 17 个下肢肌肉的 CSA 百分比变化是否在肌肉体积变化的 0.5％以内，以及（b）该测量方法的变异性与肌肉体积的变异性是否可比。我们发现，一种选择具有最高 CSA 的 MR 图像的方法，然后是一系列 CSA 测量值的方法（考虑到肌肉的数量而定），立即靠近和远离近端，可以提供肌肉体积变化的可接受估计。在股四头肌，腓肠肌，缝匠肌和胫骨前肌群中，可以通过增加 CSA 测量值之间的间隔来获得准确的结果，从而减少 MR 图像的总数，从而减少测量时间。在股二头肌的两个头，半膜肌和股薄肌中，不可能减少 CSA 测量值的数量，并且必须评估整个肌肉体积。使用这些方法，可以将估计肌肉体积变化所需的 CSA 测量值的数量减少约 60％。这些发现有助于实现更有效的方法来跟踪干预性研究中的肌肉体积变化。
