Hyperpolarized ¹³C MRI of Tumor Metabolism Demonstrates Early Metabolic Response to Neoadjuvant Chemotherapy in Breast Cancer

Purpose: To compare hyperpolarized carbon 13 (C-13) MRI with dynamic contrast material-enhanced (DCE) MRI in the detection of early treatment response in breast cancer. Materials and Methods: In this institutional review board-approved prospective study, a woman with triple-negative breast cancer (age, 49 years) underwent C-13 MRI after injection of hyperpolarized [1-carbon 13 {C-13}]-pyruvate and DCE MRI at 3 T at baseline and after one cycle of neoadjuvant therapy. The C-13-labeled lactate-to-pyruvate ratio derived from hyperpolarized C-13 MRI and the pharmacokinetic parameters transfer constant (K-trans) and washout parameter (k(ep)) derived from DCE MRI were compared before and after treatment. Results: Exchange of the C-13 label between injected hyperpolarized [1-C-13]-pyruvate and the endogenous lactate pool was observed, catalyzed by the enzyme lactate dehydrogenase. After one cycle of neoadjuvant chemotherapy, a 34% reduction in the C-13-labeled lactate-to-pyruvate ratio resulted in correct identification of the patient as a responder to therapy, which was subsequently confirmed via a complete pathologic response. However, DCE MRI showed an increase in mean K-trans (132%) and mean k(ep) (31%), which could be incorrectly interpreted as a poor response to treatment. Conclusion: Hyperpolarized C-13 MRI enabled successful identification of breast cancer response after one cycle of neoadjuvant chemotherapy and may improve response prediction when used in conjunction with multiparametric proton MRI. Published under a CC BY 4.0 license.