Abstract #4409

Investigating Lactate Pool-Size Effects in Cancer Using Metabolic Activity Decomposition and Hyperpolarized Carbon-13 MR

Christine M. Leon¹,², Larson EZ Peder¹, Ralph E. Hurd³, Robert Bok¹, Kristen R. Scott¹, John Kurhanewicz¹, Daniel B. Vigneron¹

¹Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States; ²UC Berkeley | UCSF Graduate Group in Bioengineering, University of California, Berkeley and University of California, San Francisco, San Francisco, CA , United States; ³GE Healthcare, Menlo Park, CA, United States

As hyperpolarized carbon-13 MR progresses to new disease applications and clinical research, this study investigated considerations of pool-size for accurate interpretation of HP MR dynamics. This work showed that lactate enters the cell, as it significantly affected conversion. With high co-factor availability, [1-¹³C]-lactate is less likely to convert to [1-¹³C]-pyruvate because more ¹²C-lactate molecules are available. Therefore, the lactate-to-pyruvate ratio increases in tumors even without a lactate pool-size limit and no change in K_Pyr→Lac from the significant decrease in K_Lac→Pyr. Meanwhile, normal tissues have limited NADH availability, such that the observed isotope exchange (K_Pyr→Lac) increases significantly with larger pool-sizes.