Elliott M A, Walter G A, Gulish H, Sadi A S, Lawson D D, Jaffe W, Insko E K, Leigh J S, Vandenborne K
Department of Radiology, University of Pennsylvania, Philadelphia 19104, USA.
MAGMA. 1997 Jun;5(2):93-8. doi: 10.1007/BF02592238.
Muscle mass is a determining factor in skeletal muscle function and is affected by inactivity, immobilization, disease, and aging. The aim of this study was to develop an objective and time-efficient method to quantify the volume and cross-sectional area of human calf muscles using three-dimensional magnetic resonance images. We have estimated the errors incurred in muscle volume measurements arising from artifacts known to occur in magnetic resonance imaging (MRI). The largest source of error was due to partial volume effects, which resulted in overestimation of phantom volumes ranging from 145 to 900 cc by 6% to 13%. The magnitude of this effect has been shown to increase with decreasing object size and decreasing spatial resolution. We have presented a straightforward correction for this effect, which has reduced the volume measurement error to less than 4% for all cases. Through the use of computer simulations, the correction algorithm has been shown to be independent of object shape and orientation. To reduce user subjectivity, a semiautomated computer program has been developed to segment MRI data for particular muscle groups. Images from seven human subjects were analyzed by the program, yielding muscle volumes of 154.2 +/- 23.2, 281.2 +/- 35.8, and 432.2 +/- 83.7 for the lateral gastrocnemius, medial gastrocnemius, and soleus, respectively.
肌肉量是骨骼肌功能的一个决定性因素，并且会受到缺乏运动、固定不动、疾病和衰老的影响。本研究的目的是开发一种客观且高效的方法，利用三维磁共振图像来量化人体小腿肌肉的体积和横截面积。我们估计了磁共振成像（MRI）中已知伪影在肌肉体积测量中产生的误差。最大的误差来源是部分容积效应，这导致对145至900立方厘米的体模体积高估了6%至13%。已表明这种效应的大小会随着物体尺寸减小和空间分辨率降低而增加。我们针对这种效应提出了一种直接的校正方法，在所有情况下都将体积测量误差降低到了4%以下。通过计算机模拟，已证明校正算法与物体形状和方向无关。为了减少用户主观性，开发了一个半自动计算机程序来分割特定肌肉群的MRI数据。该程序分析了来自7名人类受试者的图像，腓骨外侧肌、腓骨内侧肌和比目鱼肌的肌肉体积分别为154.2±23.2、281.2±35.8和432.2±83.7。
