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Published on: May 11, 2011
[Dynamic 31phosphorus magnetic resonance spectroscopy of the quadriceps muscle: metabolic changes under 2 different
K Schunk1, W Kersjes, S Schadmand-Fischer
1Klinik und Poliklinik für Radiologie, Johannes Gutenberg-Universität Mainz.
Purpose:
The aim of the present investigation was to examine the metabolism of the quadriceps muscles of normal young individuals using dynamic 31phosphorus magnetic resonance spectroscopy.
Methods:
22 normal individuals were examined in a 1.5T-MRT using a 6 cm surface coil. The metabolic changes in the quadriceps muscle as shown by the phosphorus spectrum were evaluated during rest, exercise (isometric and isotonic exercise) and during a 36-second period of recovery.
Results:
The Pi/PCr quotient rose from its resting value of 0.11 +/- 0.02 following exercise to a maximum of 0.83 +/- 0.47 (isometric) or 1.40 +/- 0.59 (isotonic) (difference p = 0.0001). Half-time recovery of Pi/PCr was 35 +/- 11 s or 31 +/- 10 s, respectively (p = 0.13). During the recovery phase Pi/PCr fell briefly but significantly below its rest value. Following an initial rise in pH, there was a continual fall. Minimum pH (6.68 +/- 0.21 and 6.53 +/- 0.27 respectively; p = 0.01) occurred in the early recovery phase. The recovery process of pH values lasted longer following isotonic than after isometric exercise (half-value recovery time 229 +/- 72 s and 146 +/- 55 s, respectively; p = 0.001).
Conclusion:
Compared with isometric exercise, isotonic stress is more expensive in terms of metabolism. Dynamic 31phosphorus MRT spectroscopy can differentiate changes in muscle metabolism during different forms of exercise.
