Dynamic interleaved 1H/31P STEAM MRS at 3 Tesla using a pneumatic force-controlled plantar flexion exercise rig.

ABSTRACT

OBJECTIVE: To develop a measurement method for interleaved acquisition of 1H and 31 STEAM localised spectra of exercising human calf muscle. MATERIALS AND METHODS: A non-magnetic exercise rig with a pneumatic piston and sensors for force and pedal angle was constructed to enable plantar flexion measured in the 3 T MR scanner, which holds the dual tuned (1H ,31P) surface coil used for signal transmission and reception. RESULTS: (31) spectra acquired in interleaved mode benefit from higher Signal to noise ratio (factor of 1.34 +/-0.06 for PCr) compared to standard acquisition due to the Nuclear Overhauser effect and substantial PCr/P(i) changes during exercise can be observed in 31P spectra. 1H spectral quality is equal to that in single mode experiments and allows Cr2 changes to be monitored. CONCLUSION: The feasibility of dynamic interleaved localised 1H and 31P spectroscopy during plantar flexion exercise has been demonstrated using a custom-built pneumatic system for muscle activation. This opens the possibility of studying the dynamics of metabolism with multi nuclear MRS in a single run.