Price Thomas B, Kamen Gary, Damon Bruce M, Knight Christopher A, Applegate Brooks, Gore John C, Eward Ken, Signorile Joseph F
Yale University School of Medicine, Department of Diagnostic Radiology, New Haven, CT 06510, USA.
Magn Reson Imaging. 2003 Oct;21(8):853-61. doi: 10.1016/s0730-725x(03)00183-8.
This study compared magnetic resonance imaging (MRI) and surface electromyography (EMG) to evaluate the effect of knee angle upon plantar flexion activity in the triceps surae muscles [medial & lateral gastrocnemius (MG, LG) and the soleus (SOL)]. Two weight & height matched groups performed identical protocols, twelve (6M, 6F) in the MRI group, twelve (8M, 4F) in the EMG group. Subjects plantar flexed dynamically for 2 min at 25% of 1-repetition maximum voluntary contraction (1-RM). Exercise was performed with the knee extended (0 degrees flexion), flexed (90 degrees ), and partially flexed (45 degrees ). In the MRI group spin-echo images were acquired before and immediately following each exercise session. T(2) times, calculated at rest and after exercise by fitting the echoes to a monoexponential decay pattern with a least-squares algorithm, were compared with EMG data. In the EMG group a bipolar electrode was used to collect samples were from the MG, LG, SOL, and anterior tibialis (TA) during exercise at each knee angle, MRI also examined the peroneus (PER). At 0 degrees flexion MRI demonstrated a significant post-exercise T(2) increase in the MG (p < or = 0.001), LG (p < or = 0.001), and PER (p < or = 0.01), with no T(2) change in the SOL or TA. At 90 degrees flexion there was a significant T(2) increase in the SOL (p < or = 0.001) with no significant T(2) change in the MG, LG, PER, or TA. At 45 degrees T(2) increased significantly in the SOL (p < or = 0.001) and LG (p < or = 0.05), but not the MG, PER, or TA. EMG produced similar results with the exception that there was significant activity in the TA during the relaxation cycle of the 90 degrees protocol. We conclude that: 1) Soleus activity is measurable by MRI; and 2) MRI and EMG produce similar results from different physiological sources, and are therefore complementary tools for evaluating muscle activity.
本研究比较了磁共振成像（MRI）和表面肌电图（EMG），以评估膝关节角度对小腿三头肌（内侧和外侧腓肠肌以及比目鱼肌）跖屈活动的影响。两个体重和身高匹配的组执行相同的方案，MRI组12人（6名男性，6名女性），EMG组12人（8名男性，4名女性）。受试者以1次重复最大自主收缩（1-RM）的25%进行2分钟的动态跖屈。运动在膝关节伸展（0度屈曲）、屈曲（90度）和部分屈曲（45度）状态下进行。在MRI组中，在每次运动前后采集自旋回波图像。通过使用最小二乘法算法将回波拟合为单指数衰减模式，计算静息和运动后的T(2)时间，并与EMG数据进行比较。在EMG组中，使用双极电极在每个膝关节角度运动期间从内侧腓肠肌、外侧腓肠肌、比目鱼肌和胫骨前肌采集样本，MRI还检查了腓骨肌。在0度屈曲时，MRI显示运动后内侧腓肠肌（p≤0.001）、外侧腓肠肌（p≤0.001）和腓骨肌（p≤0.01）的T(2)显著增加，比目鱼肌或胫骨前肌的T(2)无变化。在90度屈曲时，比目鱼肌的T(2)显著增加（p≤0.001），内侧腓肠肌、外侧腓肠肌、腓骨肌或胫骨前肌的T(2)无显著变化。在45度时，比目鱼肌（p≤0.001）和外侧腓肠肌（p≤0.05）的T(2)显著增加，但内侧腓肠肌、腓骨肌或胫骨前肌没有。EMG产生了类似的结果，不同的是在90度方案的放松周期中胫骨前肌有显著活动。我们得出结论：1）比目鱼肌的活动可通过MRI测量；2）MRI和EMG从不同的生理来源产生相似的结果，因此是评估肌肉活动的互补工具。
