Magnetization transfer contrast (MTC) imaging of skeletal muscle at 0.26 Tesla--changes in signal intensity following exercise

Magnetization transfer contrast (MTC) imaging of skeletal muscle before and after exercise has been studied in normal volunteers at 0.26 Tesla. A saturation pulse was applied over a range of offset frequencies immediately before a gradient recall echo sequence. Substantial signal loss was observed in all muscles. After exercise, selective saturation resulted in a significant increase of contrast between active and less active muscle, a phenomenon attributable to an increase in extracellular water content. MTC imaging provides a more sensitive method to detect changes in water distribution in human skeletal muscle.