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 KPyr→Lac from the significant decrease in KLac→Pyr. Meanwhile, normal tissues have limited NADH availability, such that the observed isotope exchange (KPyr→Lac) increases significantly with larger pool-sizes.