Yoshioka H, Itai Y
Division of Radiation Medicine, National Institute of Radiological Sciences, Chiba, Japan.
Invest Radiol. 1996 Jun;31(6):359-63. doi: 10.1097/00004424-199606000-00008.
The authors evaluate the contribution of intracellular water to the change of T2 relaxation time.
Magnetic resonance images of frog muscles (n = 16) were obtained in hypotonic, isotonic, and hypertonic solutions, and their leg weights and T2 relaxation times were measured. Likewise, these values were measured after electric stimulation for 2 to 10 minutes in isotonic solution (n = 5).
The muscle weights increased in the hypotonic solutions, whereas they showed no change in isotonic solution. T2 relaxation times, however, showed little change in either isotonic or hypotonic solutions. In electrically stimulated muscles, T2 relaxation times increased, accompanying the increase in muscle weight in isotonic solutions.
Muscle contraction results in increased T2 relaxation time, but intracellular water hardly contributes to the increase in this value. Therefore, an increase in extracellular water may be the main cause of the increase in T2 relaxation time seen in exercised muscles.
作者评估细胞内水对T2弛豫时间变化的贡献。
在低渗、等渗和高渗溶液中获取青蛙肌肉（n = 16）的磁共振图像，并测量其腿部重量和T2弛豫时间。同样，在等渗溶液中电刺激2至10分钟后（n = 5）测量这些值。
在低渗溶液中肌肉重量增加，而在等渗溶液中无变化。然而，T2弛豫时间在等渗或低渗溶液中变化很小。在电刺激的肌肉中，T2弛豫时间增加，同时等渗溶液中肌肉重量增加。
肌肉收缩导致T2弛豫时间增加，但细胞内水对该值的增加几乎没有贡献。因此，细胞外水的增加可能是运动肌肉中T2弛豫时间增加的主要原因。
