1Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States; 2Magnetic Resonance Systems Research Laboratory, Department of Electrical Engineering, Stanford University, Stanford, CA, United States; 3Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States
Magnetic resonance spectroscopy of hyperpolarized substrates provides a powerful tool to investigate metabolism. Recently, we showed that the T1,Eff of lactate was significantly shorter in tumors suggesting a different cellular environment, in addition to increased KPyr→Lac using MAD-STEAM. However, the measurement of the T1,Eff is a combination of diffusion and spin-relaxation. We modified the MAD-STEAM pulse sequence to include varying gradient strengths to separate diffusion weighting from T1 relaxation effects. This new method allows for measurements of ADCs and T1s values in addition to multiple rates of conversion, simultaneously, providing further biological information about the cellular environment of the metabolites.