MAGNETIC-RESONANCE-IMAGING AND ELECTROMYOGRAPHY AS INDEXES OF MUSCLE FUNCTION
MAGNETIC-RESONANCE-IMAGING AND ELECTROMYOGRAPHY AS INDEXES OF MUSCLE FUNCTION
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DOI：
10.1152/jappl.1992.73.4.1578
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发表时间：
1992-10-01
影响因子：
3.3
通讯作者：
DUDLEY, GA
中科院分区：
文献类型：
--
作者：
ADAMS, GR;DUVOISIN, MR;DUDLEY, GA
肌电图 (EMG) 通常用于确定收缩过程中骨骼肌的电活动。迄今为止，尚未提供肌肉使用与肌电图之间关系的独立验证。最近的研究表明，骨骼肌的松弛（例如 T2）加权磁共振图像 (MRI) 表现出运动引起的对比度增强，该增强随运动强度分级。这项研究的目的是检验以下假设：如果运动引起的磁共振 (MR) 对比度变化与肌电图振幅有关，如果这两种测量都反映了运动期间的肌肉使用情况。 MRI 和 EMG 数据均针对强度增加的单独偏心 (ECC) 和向心 (CON) 运动收集，以利用 CON 肌肉动作的 EMG 活动的增加速率和幅度明显更大这一事实。七名 30 +/- 2 (SE) 岁的受试者进行了五组 10 次 CON 或 ECC 臂弯举，每组四个阻力分别代表其 10 次 CON 弯举最大重复次数的 40%、60%、80% 和 100%。组间间隔 1.5 分钟，回合间间隔 30 分钟（5 组，每组 10 个动作，每个相对阻力）。在运动前和每次运动后立即从手臂中部 7 厘米区域收集多个回声、经轴 T2 加权 MR 图像（1.5 T，TR/TE 2,000/30）。从肱二头肌的两个头和肱三头肌的长头收集表面肌电信号。 CON 和 ECC 动作导致积分肌电图 (IEMG) 和 T2 值增加，与相对阻力密切相关 (r = 0.99，P < 0.05)。 CON 动作的 T2 和 IEMG 的增加率和绝对值均大于 ECC 动作。 CON 和 ECC 操作的 IEMG 和 T2 相关（r = 0.99，P < 0.05）。结果表明：1) 表面 IEMG 准确地反映了肌肉的收缩行为，2) 运动引起的 MRI T2 值增加反映了一些随肌肉使用而变化的过程。
Electromyography (EMG) is commonly used to determine the electrical activity of skeletal muscle during contraction. To date, independent verification of the relationship between muscle use and EMG has not been provided. It has recently been shown that relaxation- (e.g., T2) weighted magnetic resonance images (MRI) of skeletal muscle demonstrate exercise-induced contrast enhancement that is graded with exercise intensity. This study was conducted to test the hypothesis that exercise-induced magnetic resonance (MR) contrast shifts would relate to EMG amplitude if both measures reflect muscle use during exercise. Both MRI and EMG data were collected for separate eccentric (ECC) and concentric (CON) exercise of increasing intensity to take advantage of the fact that the rate of increase and amplitude of EMG activity are markedly greater for CON muscle actions. Seven subjects 30 +/- 2 (SE) yr old performed five sets of 10 CON or ECC arm curls with each of four resistances representing 40, 60, 80, and 100% of their 10 repetition maximum for CON curls. There was 1.5 min between sets and 30 min between bouts (5 sets of 10 actions at each relative resistance). Multiple echo, transaxial T2-weighted MR images (1.5 T, TR/TE 2,000/30) were collected from a 7-cm region in the middle of the arm before exercise and immediately after each bout. Surface EMG signals were collected from both heads of the biceps brachii and the long head of the triceps brachii muscles. CON and ECC actions resulted in increased integrated EMG (IEMG) and T2 values that were strongly related (r = 0.99, P < 0.05) with relative resistance. The rate of increase and absolute value of both T2 and IEMG were greater for CON than for ECC actions. IEMG and T2 for both CON and ECC actions were correlated (r = 0.99, P < 0.05). The results suggest that 1) surface IEMG accurately reflects the contractile behavior of muscle and 2) exercise-induced increases in MRI T2 values reflect some processes that scale with muscle use.