L-glutamine as a T exchange contrast agent.

PURPOSE

The potential of L-glutamine as a T exchange contrast agent in MRI was investigated.

METHODS

The T relaxation rate of L-glutamine solutions prepared in various concentrations was measured at 9.4 T. A series of T -weighted images in a mouse cancer model was acquired with an L-glutamine solution infusion.

RESULTS

The T relaxivity caused by the exchange (R ) at 37°C was 0.069 s mM and 0.102 s mM for glutamine and glutamate solutions at pH = 7.2, respectively. The R of glutamine at pH = 6.1-6.7 was in the 0.097-0.1 s mM range. No significant dependence of T on the concentration of glutamine was observed. The dynamic measurement of T -weighted images in vivo showed that the glutamine uptake was primarily observed at the localized part of the tumor CONCLUSION: L-glutamine can be used as a T exchange contrast agent and images of glutamine uptake in vivo can be acquired.